Summary: Orexin receptor type 2

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Wikipedia: Orexin receptor
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Hypocretin (orexin) receptor 2 Edit Wikipedia article

Hypocretin (orexin) receptor 2

Identifiers

Symbols

HCRTR2; OX2R

External IDs

OMIM: 602393 MGI: 2680765 HomoloGene: 1168 IUPHAR: OX₂ ChEMBL: 4792 GeneCards: HCRTR2 Gene

Gene Ontology
Molecular function	• neuropeptide receptor activity • orexin receptor activity • peptide hormone binding
Cellular component	• plasma membrane • integral to plasma membrane
Biological process	• phospholipase C-activating G-protein coupled receptor signaling pathway • neuropeptide signaling pathway • synaptic transmission • feeding behavior
Sources: Amigo / QuickGO

RNA expression pattern

More reference expression data

Orthologs

Species

Human

Mouse

RefSeq (mRNA)

RefSeq (protein)

Location (UCSC)

Chr 6:
55.04 – 55.15 Mb

Chr 9:
76.23 – 76.32 Mb

PubMed search

[1]

[2]

Orexin receptor type 2

Identifiers

Symbol

Orexin_rec2

Available protein structures:
Pfam	structures
PDB	RCSB PDB; PDBe
PDBsum	structure summary

Orexin receptor type 2 (Ox2R or OX₂), also known as hypocretin receptor type 2, is a protein that in humans is encoded by the HCRTR2 gene.^[1]

[edit] Function

OX₂ is a G-protein coupled receptor expressed exclusively in the brain. It has 64% identity with OX₁. OX₂ binds both orexin A and orexin B neuropeptides. OX₂ is involved in the central feedback mechanism that regulates feeding behaviour.^[1]

[edit] Ligands

[edit] Agonists

Orexin-A
Orexin-B
SB-668,875

[edit] Antagonists

Almorexant - mixed OX_1/2 antagonist
SB-649,868 - mixed OX_1/2 antagonist
TCS-OX2-29 - selective OX₂ antagonist
1-(2,4-dibromophenyl)-3-((4S,5S)-2,2-dimethyl-4-phenyl-[1,3]dioxan-5-yl)urea (600x selective for OX₂ over OX₁)^[2]
(3,4-dimethoxyphenoxy)alkylamino acetamides ^[3]

[edit] See also

Orexin receptor

[edit] References

^ ^a ^b "Entrez Gene: HCRTR2 hypocretin (orexin) receptor 2". http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=3062.
^ McAtee, LC; Sutton, SW; Rudolph, DA; Li, X; Aluisio, LE; Phuong, VK; Dvorak, CA; Lovenberg, TW et al. (2004). "Novel substituted 4-phenyl-1,3dioxanes: potent and selective orexin receptor 2 (OX(2)R) antagonists". Bioorganic & Medicinal Chemistry Letters 14 (16): 4225–9. doi:10.1016/j.bmcl.2004.06.032. PMID 15261275.
^ Cole, AG; Stroke, IL; Qin, LY; Hussain, Z; Simhadri, S; Brescia, MR; Waksmunski, FS; Strohl, B et al. (2008). "Synthesis of (3,4-dimethoxyphenoxy)alkylamino acetamides as orexin-2 receptor antagonists". Bioorganic & Medicinal Chemistry Letters 18 (20): 5420–3. doi:10.1016/j.bmcl.2008.09.038. PMID 18815029.

[edit] External links

"Orexin Receptors: OX₂". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology. http://www.iuphar-db.org/GPCR/ReceptorDisplayForward?receptorID=3013.

[edit] Further reading

Flier JS, Maratos-Flier E (1998). "Obesity and the hypothalamus: novel peptides for new pathways.". Cell 92 (4): 437–40. doi:10.1016/S0092-8674(00)80937-X. PMID 9491885.
Willie JT, Chemelli RM, Sinton CM, Yanagisawa M (2001). "To eat or to sleep? Orexin in the regulation of feeding and wakefulness.". Annu. Rev. Neurosci. 24: 429–58. doi:10.1146/annurev.neuro.24.1.429. PMID 11283317.
Hungs M, Mignot E (2001). "Hypocretin/orexin, sleep and narcolepsy.". BioEssays 23 (5): 397–408. doi:10.1002/bies.1058. PMID 11340621.
de Lecea L, Kilduff TS, Peyron C et al. (1998). "The hypocretins: Hypothalamus-specific peptides with neuroexcitatory activity". Proc. Natl. Acad. Sci. U.S.A. 95 (1): 322–7. doi:10.1073/pnas.95.1.322. PMC 18213. PMID 9419374. //www.ncbi.nlm.nih.gov/pmc/articles/PMC18213/.
Sakurai T, Amemiya A, Ishii M et al. (1998). "Orexins and orexin receptors: a family of hypothalamic neuropeptides and G protein-coupled receptors that regulate feeding behavior" (PDF). Cell 92 (4): 573–85. doi:10.1016/S0092-8674(00)80949-6. PMID 9491897. http://www.gghjournal.com/pdf/volume_14/14-3/14_3_leptin_ab2.pdf.
Sakurai T, Amemiya A, Ishii M et al. (1998). "Orexins and orexin receptors: a family of hypothalamic neuropeptides and G protein-coupled receptors that regulate feeding behavior". Cell 92 (5): 697. doi:10.1016/S0092-8674(02)09256-5. PMID 9527442.
Peyron C, Faraco J, Rogers W et al. (2000). "A mutation in a case of early onset narcolepsy and a generalized absence of hypocretin peptides in human narcoleptic brains". Nat. Med. 6 (9): 991–7. doi:10.1038/79690. PMID 10973318.
Wright GJ, Puklavec MJ, Willis AC et al. (2000). "Lymphoid/neuronal cell surface OX2 glycoprotein recognizes a novel receptor on macrophages implicated in the control of their function". Immunity 13 (2): 233–42. doi:10.1016/S1074-7613(00)00023-6. PMID 10981966.
Hartley JL, Temple GF, Brasch MA (2001). "DNA Cloning Using In Vitro Site-Specific Recombination". Genome Res. 10 (11): 1788–95. doi:10.1101/gr.143000. PMC 310948. PMID 11076863. //www.ncbi.nlm.nih.gov/pmc/articles/PMC310948/.
Mazzocchi G, Malendowicz LK, Gottardo L et al. (2001). "Orexin A stimulates cortisol secretion from human adrenocortical cells through activation of the adenylate cyclase-dependent signaling cascade". J. Clin. Endocrinol. Metab. 86 (2): 778–82. doi:10.1210/jc.86.2.778. PMID 11158046.
Blanco M, López M, García-Caballero T et al. (2001). "Cellular localization of orexin receptors in human pituitary". J. Clin. Endocrinol. Metab. 86 (4): 1616–9. doi:10.1210/jc.86.4.1616. PMID 11297593.
Blanco M, López M, GarcIa-Caballero T et al. (2001). "Cellular localization of orexin receptors in human pituitary". J. Clin. Endocrinol. Metab. 86 (7): 3444–7. doi:10.1210/jc.86.7.3444. PMID 11443222.
Karteris E, Randeva HS, Grammatopoulos DK et al. (2001). "Expression and coupling characteristics of the CRH and orexin type 2 receptors in human fetal adrenals". J. Clin. Endocrinol. Metab. 86 (9): 4512–9. doi:10.1210/jc.86.9.4512. PMID 11549701.
Randeva HS, Karteris E, Grammatopoulos D, Hillhouse EW (2001). "Expression of orexin-A and functional orexin type 2 receptors in the human adult adrenals: implications for adrenal function and energy homeostasis". J. Clin. Endocrinol. Metab. 86 (10): 4808–13. doi:10.1210/jc.86.10.4808. PMID 11600545.
Olafsdóttir BR, Rye DB, Scammell TE et al. (2002). "Polymorphisms in hypocretin/orexin pathway genes and narcolepsy". Neurology 57 (10): 1896–9. PMID 11723285.
Blanco M, García-Caballero T, Fraga M et al. (2002). "Cellular localization of orexin receptors in human adrenal gland, adrenocortical adenomas and pheochromocytomas". Regul. Pept. 104 (1–3): 161–5. doi:10.1016/S0167-0115(01)00359-7. PMID 11830291.
Strausberg RL, Feingold EA, Grouse LH et al. (2003). "Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences". Proc. Natl. Acad. Sci. U.S.A. 99 (26): 16899–903. doi:10.1073/pnas.242603899. PMC 139241. PMID 12477932. //www.ncbi.nlm.nih.gov/pmc/articles/PMC139241/.

This article incorporates text from the United States National Library of Medicine, which is in the public domain.

Cell surface receptor: G protein-coupled receptors

Class A:
Rhodopsin like

Neurotransmitter

Adrenergic	α1 (A B D) α2 (A B C) β1 β2 β3

Purinergic	Adenosine (A1 A2A A2B A3) P2Y (1 2 4 5 6 8 9 10 11 12 13 14)

Serotonin	(all but 5-HT3) 5-HT1 (A B D E F) 5-HT2 (A B C) 5-HT (4 5A 6 7)

Other	Acetylcholine (M1 M2 M3 M4 M5) Dopamine (D1 D2 D3 D4 D5) Histamine (H1 H2 H3 H4) Melatonin (1A 1B 1C) TAAR (1 2 3 5 6 8 9)

Metabolites and
signaling molecules

Eicosanoid	CysLT (1 2) LTB4 (1 2) FPRL1 OXE Prostaglandin (DP (1 2), EP (1 2 3 4), FP) Prostacyclin Thromboxane

Other	Bile acid Cannabinoid (CB1 CB2, GPR (18 55 119)) EBI2 Estrogen Free fatty acid (1 2 3 4) Lactate Lysophosphatidic acid (1 2 3 4 5 6) Lysophospholipid (1 2 3 4 5 6 7 8) Niacin (1 2) Oxoglutarate PAF Sphingosine-1-phosphate (1 2 3 4 5) Succinate

Peptide

Neuropeptide	B/W (1 2) FF (1 2) S Y (1 2 4 5) Neuromedin (B U (1 2)) Neurotensin (1 2)

Other	Anaphylatoxin (C3a C5a) Angiotensin (1 2) Apelin Bombesin (BRS3 GRPR NMBR) Bradykinin (B1 B2) Chemokine Cholecystokinin (A B) Endothelin (A B) Formyl peptide (1 2 3) FSH Galanin (1 2 3) GHB receptor Gonadotropin-releasing hormone (1 2) Ghrelin Kisspeptin Luteinizing hormone/choriogonadotropin MAS (1 1L D E F G X1 X2 X3 X4) Melanocortin (1 2 3 4 5) MCHR (1 2) Motilin Opioid (Delta Kappa Mu Nociceptin & Zeta, but not Sigma) Orexin (1 2) Oxytocin Prokineticin (1 2) Prolactin-releasing peptide Relaxin (1 2 3 4) Somatostatin (1 2 3 4 5) Tachykinin (1 2 3) Thyrotropin Thyrotropin-releasing hormone Urotensin-II Vasopressin (1A 1B 2)

Miscellaneous

Orphan	GPR (1 3 4 6 12 15 17 18 19 20 21 22 23 25 26 27 31 32 33 34 35 37 39 42 44 45 50 52 55 61 62 63 65 68 75 77 78 81 82 83 84 85 87 88 92 101 103 109A 109B 119 120 132 135 137B 139 141 142 146 148 149 150 151 152 153 160 161 162 171 173 174 176 177 182 183)

Other	Adrenomedullin Olfactory Opsin (3 4 5 1LW 1MW 1SW RGR RRH) Protease-activated (1 2 3 4) SREB (1 2 3)

Class B: Secretin like

Orphan	GPR (56 64 97 98 110 111 112 113 114 115 116 123 124 125 126 128 133 143 144 155 157)

Other	Brain-specific angiogenesis inhibitor (1 2 3) Cadherin (1 2 3) Calcitonin CALCRL CD97 Corticotropin-releasing hormone (1 2) EMR (1 2 3) Glucagon (GR GIPR GLP1R GLP2R) Growth hormone releasing hormone PACAPR1 GPR Latrophilin (1 2 3 ELTD1) Methuselah-like proteins Parathyroid hormone (1 2) Secretin Vasoactive intestinal peptide (1 2)

Class C: Metabotropic
glutamate / pheromone

Taste	TAS1R (1 2 3) TAS2R (1 3 4 5 7 8 9 10 13 14 16 19 20 30 31 38 39 40 41 42 43 45 46 50 60)

Other	Calcium-sensing receptor GABA B (1 2) Glutamate receptor (Metabotropic glutamate (1 2 3 4 5 6 7 8)) GPRC6A GPR (156 158 179) RAIG (1 2 3 4)

Class F:
Frizzled / Smoothened

Frizzled	Frizzled (1 2 3 4 5 6 7 8 9 10)

Smoothened	Smoothened

B trdu: iter (nrpl/grfl/cytl/horl), csrc (lgic, enzr, gprc, igsr, intg, nrpr/grfr/cytr), itra (adap, gbpr, mapk), calc, lipd; path (hedp, wntp, tgfp+mapp, notp, jakp, fsap, hipp, tlrp)

Neuropeptidergics

Cholecystokinin

CCK_A	Agonists: Cholecystokinin CCK-4 Antagonists: Asperlicin Proglumide Lorglumide Devazepide Dexloxiglumide

CCK_B	Agonists: Cholecystokinin CCK-4 Gastrin Antagonists: Proglumide CI-988

CRH

CRF₁	Agonists: Corticotropin releasing hormone Antagonists: Antalarmin CP-154,526 Pexacerfont

CRF₂	Agonists: Corticotropin releasing hormone

Galanin

GAL₁	Agonists: Galanin Galanin-like peptide Galmic Galnon

GAL₂	Agonists: Galanin Galanin-like peptide Galmic Galnon

GAL₃	Agonists: Galanin Galmic Galnon

Ghrelin

GnRH

MCH

MCH₁	Agonists: Melanin concentrating hormone Antagonists: ATC-0175 GW-803,430 NGD-4715 SNAP-7941 SNAP-94847

MCH₂	Agonists: Melanin concentrating hormone

Melanocortin

MC₁	Agonists: alpha-MSH Afamelanotide BMS-470,539 Bremelanotide Melanotan II Antagonists: Agouti signalling peptide

MC₂	Agonists: ACTH Cosyntropin Tetracosactide

MC₃	Agonists: alpha-MSH Bremelanotide Melanotan II

MC₄	Agonists: alpha-MSH Bremelanotide Melanotan II PF-00446687 THIQ Antagonists: Agouti-related peptide

MC₅	Agonists: alpha-MSH Melanotan II

Neuropeptide S

Agonists: Neuropeptide S
Antagonists: SHA-68

Neuropeptide Y

Y₁	Agonists: Neuropeptide Y Peptide YY Antagonists: BIBP-3226

Y₂	Agonists: Neuropeptide Y Peptide YY Antagonists: BIIE-0246

Y₄	Agonists: Neuropeptide Y Pancreatic polypeptide Peptide YY Antagonists: UR-AK49

Y₅	Agonists: Neuropeptide Y Peptide YY Antagonists: Lu AA-33810

Neurotensin

NTS₁	Agonists: Neurotensin Neuromedin N Antagonists: SR-48692 SR-142,948

NTS₂	Agonists: Neurotensin Antagonists: Levocabastine SR-142,948

Orexin

OX₁	Agonists: Orexin-A Antagonists: Almorexant SB-334,867 SB-408,124 SB-649,868 Suvorexant

OX₂	Agonists: Orexin-A Antagonists: Almorexant SB-649,868 Suvorexant TCS-OX2-29

Oxytocin

Tachykinin

NK₁	Agonists: Substance P Antagonists: Aprepitant Befetupitant Casopitant CI-1021 CP-96,345 CP-99,994 CP-122,721 Dapitant Ezlopitant FK-888 Fosaprepitant GR-203,040 GW-597,599 HSP-117 L-733,060 L-741,671 L-743,310 L-758,298 Lanepitant LY-306,740 Maropitant Netupitant NKP-608 Nolpitantium Orvepitant RP-67,580 SDZ NKT 343 Vestipitant Vofopitant

NK₂	Agonists: Neurokinin A Antagonists: GR-159,897 Ibodutant Saredutant

NK₃	Agonists: Neurokinin B Antagonists: Osanetant Talnetant

Vasopressin

V_1A	Agonists: Desmopressin Felypressin Ornipressin Terlipressin Vasopressin Antagonists: Conivaptan Demeclocycline Relcovaptan

V_1B	Agonists: Felypressin Ornipressin Terlipressin Vasopressin Antagonists: Demeclocycline Nelivaptan

V₂	Agonists: Desmopressin Ornipressin Vasopressin Antagonists: Conivaptan Demeclocycline Lixivaptan Mozavaptan Satavaptan Tolvaptan

This transmembrane receptor-related article is a stub. You can help Wikipedia by expanding it.

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This is the Wikipedia entry entitled "Orexin receptor". More...

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Orexin receptor Edit Wikipedia article

hypocretin (orexin) receptor 1
Identifiers
Symbol	HCRTR1
Entrez	3061
HUGO	4848
OMIM	602392
RefSeq	NM_001525
UniProt	O43613
Other data
Locus	Chr. 1 p33

hypocretin (orexin) receptor 2
Identifiers
Symbol	HCRTR2
Entrez	3062
HUGO	4849
OMIM	602393
RefSeq	NM_001526
UniProt	O43614
Other data
Locus	Chr. 6 p11-q11

Orexin receptor type 2

Identifiers

Symbol

Orexin_rec2

Available protein structures:
Pfam	structures
PDB	RCSB PDB; PDBe
PDBsum	structure summary

The orexin receptor (also referred to as the hypocretin receptor) is a G-protein-coupled receptor that binds the neuropeptide hormone orexin. There are two variants, OX₁ and OX₂, each encoded by a different gene (HCRTR1, HCRTR2).^[1]

Both orexin receptors exhibit a similar pharmacology - the 2 orexin peptides, orexin-A and orexin-B, bind to both receptors and, in each case, agonist binding results in an increase in intracellular calcium levels. However, orexin-B shows a 10-fold selectivity for orexin receptor type 2, whilst orexin-A is equipotent at both receptors.^[2]

Several orexin receptor antagonists are in development for potential use in sleep disorders.

[edit] References

^ Spinazzi R, Andreis PG, Rossi GP, Nussdorfer GG (2006). "Orexins in the regulation of the hypothalamic-pituitary-adrenal axis". Pharmacol. Rev. 58 (1): 46–57. doi:10.1124/pr.58.1.4. PMID 16507882.
^ Smart D, Jerman JC, Brough SJ, Rushton SL, Murdock PR, Jewitt F, Elshourbagy NA, Ellis CE, Middlemiss DN, Brown F (September 1999). "Characterization of recombinant human orexin receptor pharmacology in a Chinese hamster ovary cell-line using FLIPR". Br. J. Pharmacol. 128 (1): 1–3. doi:10.1038/sj.bjp.0702780. PMC 1571615. PMID 10498827. //www.ncbi.nlm.nih.gov/pmc/articles/PMC1571615/.

[edit] External links

"Orexin Receptors". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology. http://www.iuphar-db.org/GPCR/ChapterMenuForward?chapterID=1346.
Orexin Receptors at the US National Library of Medicine Medical Subject Headings (MeSH)

This transmembrane receptor-related article is a stub. You can help Wikipedia by expanding it.

Cell surface receptor: G protein-coupled receptors

Class A:
Rhodopsin like

Neurotransmitter

Adrenergic	α1 (A B D) α2 (A B C) β1 β2 β3

Purinergic	Adenosine (A1 A2A A2B A3) P2Y (1 2 4 5 6 8 9 10 11 12 13 14)

Serotonin	(all but 5-HT3) 5-HT1 (A B D E F) 5-HT2 (A B C) 5-HT (4 5A 6 7)

Other	Acetylcholine (M1 M2 M3 M4 M5) Dopamine (D1 D2 D3 D4 D5) Histamine (H1 H2 H3 H4) Melatonin (1A 1B 1C) TAAR (1 2 3 5 6 8 9)

Metabolites and
signaling molecules

Eicosanoid	CysLT (1 2) LTB4 (1 2) FPRL1 OXE Prostaglandin (DP (1 2), EP (1 2 3 4), FP) Prostacyclin Thromboxane

Other	Bile acid Cannabinoid (CB1 CB2, GPR (18 55 119)) EBI2 Estrogen Free fatty acid (1 2 3 4) Lactate Lysophosphatidic acid (1 2 3 4 5 6) Lysophospholipid (1 2 3 4 5 6 7 8) Niacin (1 2) Oxoglutarate PAF Sphingosine-1-phosphate (1 2 3 4 5) Succinate

Peptide

Neuropeptide	B/W (1 2) FF (1 2) S Y (1 2 4 5) Neuromedin (B U (1 2)) Neurotensin (1 2)

Other	Anaphylatoxin (C3a C5a) Angiotensin (1 2) Apelin Bombesin (BRS3 GRPR NMBR) Bradykinin (B1 B2) Chemokine Cholecystokinin (A B) Endothelin (A B) Formyl peptide (1 2 3) FSH Galanin (1 2 3) GHB receptor Gonadotropin-releasing hormone (1 2) Ghrelin Kisspeptin Luteinizing hormone/choriogonadotropin MAS (1 1L D E F G X1 X2 X3 X4) Melanocortin (1 2 3 4 5) MCHR (1 2) Motilin Opioid (Delta Kappa Mu Nociceptin & Zeta, but not Sigma) Orexin (1 2) Oxytocin Prokineticin (1 2) Prolactin-releasing peptide Relaxin (1 2 3 4) Somatostatin (1 2 3 4 5) Tachykinin (1 2 3) Thyrotropin Thyrotropin-releasing hormone Urotensin-II Vasopressin (1A 1B 2)

Miscellaneous

Orphan	GPR (1 3 4 6 12 15 17 18 19 20 21 22 23 25 26 27 31 32 33 34 35 37 39 42 44 45 50 52 55 61 62 63 65 68 75 77 78 81 82 83 84 85 87 88 92 101 103 109A 109B 119 120 132 135 137B 139 141 142 146 148 149 150 151 152 153 160 161 162 171 173 174 176 177 182 183)

Other	Adrenomedullin Olfactory Opsin (3 4 5 1LW 1MW 1SW RGR RRH) Protease-activated (1 2 3 4) SREB (1 2 3)

Class B: Secretin like

Orphan	GPR (56 64 97 98 110 111 112 113 114 115 116 123 124 125 126 128 133 143 144 155 157)

Other	Brain-specific angiogenesis inhibitor (1 2 3) Cadherin (1 2 3) Calcitonin CALCRL CD97 Corticotropin-releasing hormone (1 2) EMR (1 2 3) Glucagon (GR GIPR GLP1R GLP2R) Growth hormone releasing hormone PACAPR1 GPR Latrophilin (1 2 3 ELTD1) Methuselah-like proteins Parathyroid hormone (1 2) Secretin Vasoactive intestinal peptide (1 2)

Class C: Metabotropic
glutamate / pheromone

Taste	TAS1R (1 2 3) TAS2R (1 3 4 5 7 8 9 10 13 14 16 19 20 30 31 38 39 40 41 42 43 45 46 50 60)

Other	Calcium-sensing receptor GABA B (1 2) Glutamate receptor (Metabotropic glutamate (1 2 3 4 5 6 7 8)) GPRC6A GPR (156 158 179) RAIG (1 2 3 4)

Class F:
Frizzled / Smoothened

Frizzled	Frizzled (1 2 3 4 5 6 7 8 9 10)

Smoothened	Smoothened

B trdu: iter (nrpl/grfl/cytl/horl), csrc (lgic, enzr, gprc, igsr, intg, nrpr/grfr/cytr), itra (adap, gbpr, mapk), calc, lipd; path (hedp, wntp, tgfp+mapp, notp, jakp, fsap, hipp, tlrp)

Neuropeptidergics

Cholecystokinin

CCK_A	Agonists: Cholecystokinin CCK-4 Antagonists: Asperlicin Proglumide Lorglumide Devazepide Dexloxiglumide

CCK_B	Agonists: Cholecystokinin CCK-4 Gastrin Antagonists: Proglumide CI-988

CRH

CRF₁	Agonists: Corticotropin releasing hormone Antagonists: Antalarmin CP-154,526 Pexacerfont

CRF₂	Agonists: Corticotropin releasing hormone

Galanin

GAL₁	Agonists: Galanin Galanin-like peptide Galmic Galnon

GAL₂	Agonists: Galanin Galanin-like peptide Galmic Galnon

GAL₃	Agonists: Galanin Galmic Galnon

Ghrelin

GnRH

MCH

MCH₁	Agonists: Melanin concentrating hormone Antagonists: ATC-0175 GW-803,430 NGD-4715 SNAP-7941 SNAP-94847

MCH₂	Agonists: Melanin concentrating hormone

Melanocortin

MC₁	Agonists: alpha-MSH Afamelanotide BMS-470,539 Bremelanotide Melanotan II Antagonists: Agouti signalling peptide

MC₂	Agonists: ACTH Cosyntropin Tetracosactide

MC₃	Agonists: alpha-MSH Bremelanotide Melanotan II

MC₄	Agonists: alpha-MSH Bremelanotide Melanotan II PF-00446687 THIQ Antagonists: Agouti-related peptide

MC₅	Agonists: alpha-MSH Melanotan II

Neuropeptide S

Agonists: Neuropeptide S
Antagonists: SHA-68

Neuropeptide Y

Y₁	Agonists: Neuropeptide Y Peptide YY Antagonists: BIBP-3226

Y₂	Agonists: Neuropeptide Y Peptide YY Antagonists: BIIE-0246

Y₄	Agonists: Neuropeptide Y Pancreatic polypeptide Peptide YY Antagonists: UR-AK49

Y₅	Agonists: Neuropeptide Y Peptide YY Antagonists: Lu AA-33810

Neurotensin

NTS₁	Agonists: Neurotensin Neuromedin N Antagonists: SR-48692 SR-142,948

NTS₂	Agonists: Neurotensin Antagonists: Levocabastine SR-142,948

Orexin

OX₁	Agonists: Orexin-A Antagonists: Almorexant SB-334,867 SB-408,124 SB-649,868 Suvorexant

OX₂	Agonists: Orexin-A Antagonists: Almorexant SB-649,868 Suvorexant TCS-OX2-29

Oxytocin

Tachykinin

NK₁	Agonists: Substance P Antagonists: Aprepitant Befetupitant Casopitant CI-1021 CP-96,345 CP-99,994 CP-122,721 Dapitant Ezlopitant FK-888 Fosaprepitant GR-203,040 GW-597,599 HSP-117 L-733,060 L-741,671 L-743,310 L-758,298 Lanepitant LY-306,740 Maropitant Netupitant NKP-608 Nolpitantium Orvepitant RP-67,580 SDZ NKT 343 Vestipitant Vofopitant

NK₂	Agonists: Neurokinin A Antagonists: GR-159,897 Ibodutant Saredutant

NK₃	Agonists: Neurokinin B Antagonists: Osanetant Talnetant

Vasopressin

V_1A	Agonists: Desmopressin Felypressin Ornipressin Terlipressin Vasopressin Antagonists: Conivaptan Demeclocycline Relcovaptan

V_1B	Agonists: Felypressin Ornipressin Terlipressin Vasopressin Antagonists: Demeclocycline Nelivaptan

V₂	Agonists: Desmopressin Ornipressin Vasopressin Antagonists: Conivaptan Demeclocycline Lixivaptan Mozavaptan Satavaptan Tolvaptan

This article incorporates text from the public domain Pfam and InterPro IPR004060

This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

Orexin receptor type 2 Provide feedback

No Pfam abstract.

External database links

PANDIT:	PF03827
Pseudofam:	PF03827
SYSTERS:	Orexin_rec2

This tab holds annotation information from the InterPro database.

InterPro entry IPR004060

G-protein-coupled receptors, GPCRs, constitute a vast protein family that encompasses a wide range of functions (including various autocrine, paracrine and endocrine processes). They show considerable diversity at the sequence level, on the basis of which they can be separated into distinct groups. We use the term clan to describe the GPCRs, as they embrace a group of families for which there are indications of evolutionary relationship, but between which there is no statistically significant similarity in sequence [PUBMED:8170923]. The currently known clan members include the rhodopsin-like GPCRs, the secretin-like GPCRs, the cAMP receptors, the fungal mating pheromone receptors, and the metabotropic glutamate receptor family. There is a specialised database for GPCRs (http://www.gpcr.org/7tm/).

The rhodopsin-like GPCRs themselves represent a widespread protein family that includes hormone, neurotransmitter and light receptors, all of which transduce extracellular signals through interaction with guanine nucleotide-binding (G) proteins. Although their activating ligands vary widely in structure and character, the amino acid sequences of the receptors are very similar and are believed to adopt a common structural framework comprising 7 transmembrane (TM) helices [PUBMED:2111655, PUBMED:2830256, PUBMED:8386361].

The hypothalamus plays a central role in the integrated control of feeding and energy homeostasis [PUBMED:9491897]. A new family of neuropeptides, orexins, have been identified that bind and activate two closely related (previously) orphan GPCRs [PUBMED:9491897, PUBMED:9656726]. Orexins stimulate appetite and food consumption [PUBMED:9656726]. Their genes are expressed bilaterally and symmetrically in the lateral hypothalamus, which has been shown to be the "feeding centre". By contrast, the "satiety centre" is expressed in the ventromedial hypothalamus and is dominated by the leptin-regulated neuropeptide network.

Both orexin receptors exhibit a similar pharmacology - the 2 orexin peptides, orexin-A and orexin-B, bind to both receptors and, in each case, agonist binding results in an increase in intracellular calcium levels. However, orexin-B shows a 10-fold selectivity for orexin receptor type 2, whilst orexin-A is equipotent at both receptors [PUBMED:10498827].

Gene Ontology

The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.

Cellular component	integral to membrane (GO:0016021)
Molecular function	orexin receptor activity (GO:0016499)
Biological process	G-protein coupled receptor signaling pathway (GO:0007186)

Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

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Alignments

We store a range of different sequence alignments for families. As well as the seed alignment from which the family is built, we provide the full alignment, generated by searching the sequence database using the family HMM. We also generate alignments using four representative proteomes (RP) sets, the NCBI sequence database, and our metagenomics sequence database. More...

There are various ways to view or download the sequence alignments that we store. We provide several sequence viewers and a plain-text Stockholm-format file for download.

Alignment types

We make a range of alignments for each Pfam-A family:

seed: the curated alignment from which the HMM for the family is built
full: the alignment generated by searching the sequence database using the HMM
RP15/RP35/RP55/RP75: Representative Proteomes (RPs) at 15%, 35%, 55% and 75% co-membership thresholds
NCBI: alignment generated by searching the NCBI sequence database using the family HMM
meta: alignment generated by searching the metagenomics sequence database using the family HMM

Viewing

You can see the alignments as HTML or in three different sequence viewers:

jalview: a Java applet developed at the University of Dundee. You will need Java installed before running jalview
HTML: an HTML page showing the whole alignment.Please note: full Pfam alignments can be very large. These HTML views are extremely large and often cause problems for browsers. Please use either jalview or the Pfam viewer if you have trouble viewing the HTML version
PP/Heatmap: an HTML-based representation of the alignment, coloured according to the posterior-probability (PP) values from the HMM. As for the standard HTML view, heatmap alignments can also be very large and slow to render.
Pfam viewer: an HTML-based viewer that uses DAS to retrieve alignment fragments on request

Reformatting

You can download (or view in your browser) a text representation of a Pfam alignment in various formats:

Selex
Stockholm
FASTA
MSF

You can also change the order in which sequences are listed in the alignment, change how insertions are represented, alter the characters that are used to represent gaps in sequences and, finally, choose whether to download the alignment or to view it in your browser directly.

Downloading

You may find that large alignments cause problems for the viewers and the reformatting tool, so we also provide all alignments in Stockholm format. You can download either the plain text alignment, or a gzipped version of it.

View options

We make a range of alignments for each Pfam-A family. You can see a description of each above. You can view these alignments in various ways but please note that some types of alignment are never generated while others may not be available for all families, most commonly because the alignments are too large to handle.

	Seed (3)	Full (46)	Representative proteomes				NCBI (36)	Meta (0)
	Seed (3)	Full (46)	RP15 (1)	RP35 (4)	RP55 (12)	RP75 (28)	NCBI (36)	Meta (0)
Jalview	View	View	View	View	View	View	View
HTML	View	View	View	View	View	View
PP/heatmap	₁	View	View	View	View	View
Pfam viewer	View	View

¹Cannot generate PP/Heatmap alignments for seeds; no PP data available

Key: available, not generated, — not available.

Format an alignment

	Seed (3)	Full (46)	Representative proteomes				NCBI (36)	Meta (0)
	Seed (3)	Full (46)	RP15 (1)	RP35 (4)	RP55 (12)	RP75 (28)	NCBI (36)	Meta (0)
Alignment:
Format:
Order:	Tree Alphabetical
Sequence:	Inserts lower case All upper case
Gaps:
Download/view:	Download View

Download options

We make all of our alignments available in Stockholm format. You can download them here as raw, plain text files or as gzip-compressed files.

	Seed (3)	Full (46)	Representative proteomes				NCBI (36)	Meta (0)
	Seed (3)	Full (46)	RP15 (1)	RP35 (4)	RP55 (12)	RP75 (28)	NCBI (36)	Meta (0)
Raw Stockholm	Download	Download	Download	Download	Download	Download	Download
Gzipped	Download	Download	Download	Download	Download	Download	Download

You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

External links

MyHits provides a collection of tools to handle multiple sequence alignments. For example, one can refine a seed alignment (sequence addition or removal, re-alignment or manual edition) and then search databases for remote homologs using HMMER3.

HMM logo

HMM logos is one way of visualising profile HMMs. Logos provide a quick overview of the properties of an HMM in a graphical form. You can see a more detailed description of HMM logos and find out how you can interpret them here. More...

Trees

This page displays the phylogenetic tree for this family's seed alignment. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed alignment.

Note: You can also download the data file for the tree.

Curation and family details

This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.

Curation

Seed source:

PRINTS

Previous IDs:

none

Type:

Family

Author:

Griffiths-Jones SR

Number in seed:

3

Number in full:

46

Average length of the domain:

57.30 aa

Average identity of full alignment:

70 %

Average coverage of the sequence by the domain:

13.61 %

HMM information

HMM build commands:

build method: hmmbuild -o /dev/null HMM SEED

search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq

Model details:

Parameter	Sequence	Domain
Gathering cut-off	25.0	25.0
Trusted cut-off	28.2	27.0
Noise cut-off	21.9	18.7

Model length:

61

Family (HMM) version:

8

Download:

download the raw HMM for this family

Species distribution

Sunburst
Tree

Sunburst controls

Show

This visualisation provides a simple graphical representation of the distribution of this family across species. You can find the original interactive tree in the adjacent tab. More...

This chart is a modified "sunburst" visualisation of the species tree for this family. It shows each node in the tree as a separate arc, arranged radially with the superkingdoms at the centre and the species arrayed around the outermost ring.

How the sunburst is generated

The tree is built by considering the taxonomic lineage of each sequence that has a match to this family. For each node in the resulting tree, we draw an arc in the sunburst. The radius of the arc, its distance from the root node at the centre of the sunburst, shows the taxonomic level ("superkingdom", "kingdom", etc). The length of the arc represents either the number of sequences represented at a given level, or the number of species that are found beneath the node in the tree. The weighting scheme can be changed using the sunburst controls.

In order to reduce the complexity of the representation, we reduce the number of taxonomic levels that we show. We consider only the following eight major taxonomic levels:

superkingdom
kingdom
phylum
class
order
family
genus
species

Colouring and labels

Segments of the tree are coloured approximately according to their superkingdom. For example, archeal branches are coloured with shades of orange, eukaryotes in shades of purple, etc. The colour assignments are shown under the sunburst controls. Where space allows, the name of the taxonomic level will be written on the arc itself.

As you move your mouse across the sunburst, the current node will be highlighted. In the top section of the controls panel we show a summary of the lineage of the currently highlighed node. If you pause over an arc, a tooltip will be shown, giving the name of the taxonomic level in the title and a summary of the number of sequences and species below that node in the tree.

Anomalies in the taxonomy tree

There are some situations that the sunburst tree cannot easily handle and for which we have work-arounds in place.

Missing taxonomic levels

Some species in the taxonomic tree may not have one or more of the main eight levels that we display. For example, Bos taurus is not assigned an order in the NCBI taxonomic tree. In such cases we mark the omitted level with, for example, "No order", in both the tooltip and the lineage summary.

Unmapped species names

The tree is built by looking at each sequence in the full alignment for the family. We take the name of the species given by UniProt and try to map that to the full taxonomic tree from NCBI. In some cases, the name chosen by UniProt does not map to any node in the NCBI tree, perhaps because the chosen name is listed as a synonym or a misspelling in the NCBI taxonomy.

So that these nodes are not simply omitted from the sunburst tree, we group them together in a separate branch (or segment of the sunburst tree). Since we cannot determine the lineage for these unmapped species, we show all levels between the superkingdom and the species as "uncategorised".

Sub-species

Since we reduce the species tree to only the eight main taxonomic levels, sequences that are mapped to the sub-species level in the tree would not normally be shown. Rather than leave out these species, we map them instead to their parent species. So, for example, for sequences belonging to one of the Vibrio cholerae sub-species in the NCBI taxonomy, we show them instead as belonging to the species Vibrio cholerae.

Too many species/sequences

For large species trees, you may see blank regions in the outer layers of the sunburst. These occur when there are large numbers of arcs to be drawn in a small space. If an arc is less than approximately one pixel wide, it will not be drawn and the space will be left blank. You may still be able to get some information about the species in that region by moving your mouse across the area, but since each arc will be very small, it will be difficult to accurately locate a particular species.

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Tree controls

Hide

The tree shows the occurrence of this domain across different species. More...

Species trees

We show the species tree in one of two ways. For smaller trees we try to show an interactive representation, which allows you to select specific nodes in the tree and view them as an alignment or as a set of Pfam domain graphics.

Unfortunately we have found that there are problems viewing the interactive tree when the it becomes larger than a certain limit. Furthermore, we have found that Internet Explorer can become unresponsive when viewing some trees, regardless of their size. We therefore show a text representation of the species tree when the size is above a certain limit or if you are using Internet Explorer to view the site.

If you are using IE you can still load the interactive tree by clicking the "Generate interactive tree" button, but please be aware of the potential problems that the interactive species tree can cause.

Interactive tree

For all of the domain matches in a full alignment, we count the number that are found on all sequences in the alignment. This total is shown in the purple box.

We also count the number of unique sequences on which each domain is found, which is shown in green. Note that a domain may appear multiple times on the same sequence, leading to the difference between these two numbers.

Finally, we group sequences from the same organism according to the NCBI code that is assigned by UniProt, allowing us to count the number of distinct sequences on which the domain is found. This value is shown in the pink boxes.

We use the NCBI species tree to group organisms according to their taxonomy and this forms the structure of the displayed tree. Note that in some cases the trees are too large (have too many nodes) to allow us to build an interactive tree, but in most cases you can still view the tree in a plain text, non-interactive representation. Those species which are represented in the seed alignment for this domain are highlighted.

You can use the tree controls to manipulate how the interactive tree is displayed:

show/hide the summary boxes
highlight species that are represented in the seed alignment
expand/collapse the tree or expand it to a given depth
select a sub-tree or a set of species within the tree and view them graphically or as an alignment
save a plain text representation of the tree

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Please note: for large trees this can take some time. While the tree is loading, you can safely switch away from this tab but if you browse away from the family page entirely, the tree will not be loaded.

Archea	Eukaryota
Bacteria	Other sequences
Viruses	Unclassified
Viroids	Unclassified sequence

Family: Orexin_rec2 (PF03827)

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Summary: Orexin receptor type 2

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Hypocretin (orexin) receptor 2 Edit Wikipedia article

Contents

[edit] Function

[edit] Ligands

[edit] Agonists

[edit] Antagonists

[edit] See also

[edit] References

[edit] External links

[edit] Further reading

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Orexin receptor Edit Wikipedia article

[edit] References

[edit] External links

Orexin receptor type 2 Provide feedback

External database links

InterPro entry IPR004060

Gene Ontology

Domain organisation

Alignments

Alignment types

Viewing

Reformatting

Downloading

View options

Format an alignment

Download options

External links

HMM logo

Trees

Curation and family details

Curation

HMM information

Species distribution

Sunburst controls

Weight segments by...

Change the size of the sunburst

Colour assignments

Selections

Currently selected:

How the sunburst is generated

Colouring and labels

Anomalies in the taxonomy tree

Missing taxonomic levels

Unmapped species names

Sub-species

Too many species/sequences

Tree controls

Annotation

Download tree

Selected sequences

Species trees

Interactive tree