Summary: Insulin/IGF/Relaxin family
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Insulin/IGF/Relaxin family Edit Wikipedia article
| Insulin/IGF/Relaxin family | |||||||||
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PDB rendering based on 1ai0. |
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| Identifiers | |||||||||
| Symbol | Insulin | ||||||||
| Pfam | PF00049 | ||||||||
| Pfam clan | CL0239 | ||||||||
| InterPro | IPR004825 | ||||||||
| PROSITE | PDOC00235 | ||||||||
| SCOP | 1cph | ||||||||
| SUPERFAMILY | 1cph | ||||||||
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The insulin/IGF/relaxin family is a group of evolutionary related proteins which possess a variety of hormonal activities.[1] Family members in human include two subfamilies:
1) insulin and insulin-like growth factors[2]
2) relaxin family peptides:
- relaxin 1 and 2
- relaxin 3
- Leydig cell-specific insulin-like peptide (gene INSL3)[3]
- early placenta insulin-like peptide (ELIP) (gene INSL4)[4]
- insulin-like peptide 5 (gene INSL5)
- insulin-like peptide 6
[edit] Structure
These proteins are characterized by having three disulfide bonds in a characteristic motif. Some family members have an additional disulfide bond also in a conserved location. All of these proteins have a helical segment (corresponding to B chain in insulin) followed by a variable-length chain, followed by a domain (A chain in insulin) with two helices pinned against each other via a disulfide bond. These two regions are linked by two or three disulfide bonds.
Amongst the different proteins in the family, very little of the sequence is conserved except for the disulfide bonds. The variable-length chains may exhibit large inter-species variation even when the remaider of the sequence is highly conserved; and as is in the case of insulin, sometimes the variable length chain is cleaved out by secretory endoproteases, leaving a two-chain protein held together by disulfide bonds.
[edit] See also
Relaxin family peptide hormones
Relaxin/insulin-like family peptide receptor 1
[edit] References
- ^ Blundell TL, Humbel RE (October 1980). "Hormone families: pancreatic hormones and homologous growth factors". Nature 287 (5785): 781–7. doi:10.1038/287781a0. PMID 6107857.
- ^ Humbel RE (July 1990). "Insulin-like growth factors I and II". European journal of biochemistry / FEBS 190 (3): 445–62. doi:10.1111/j.1432-1033.1990.tb15595.x. PMID 2197088.
- ^ Adham IM, Burkhardt E, Benahmed M, Engel W (December 1993). "Cloning of a cDNA for a novel insulin-like peptide of the testicular Leydig cells". The Journal of Biological Chemistry 268 (35): 26668–72. PMID 8253799.
- ^ Chassin D, Laurent A, Janneau JL, Berger R, Bellet D (September 1995). "Cloning of a new member of the insulin gene superfamily (INSL4) expressed in human placenta". Genomics 29 (2): 465–70. doi:10.1006/geno.1995.9980. PMID 8666396.
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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.
Insulin/IGF/Relaxin family Provide feedback
Superfamily includes insulins; relaxins; insulin-like growth factor; and bombyxin. All are secreted regulatory hormones. Disulfide rich, all-alpha fold. Alignment includes B chain, linker (which is processed out of the final product), and A chain.
External database links
| HOMSTRAD: | ins |
| PANDIT: | PF00049 |
| PRINTS: | PR00276 |
| PROSITE: | PDOC00235 |
| Pseudofam: | PF00049 |
| SCOP: | 1cph |
| SYSTERS: | Insulin |
This tab holds annotation information from the InterPro database.
InterPro entry IPR016179
The insulin family of proteins groups together several evolutionarily related active peptides [PUBMED:6107857]: these include insulin [PUBMED:6243748, PUBMED:503234], relaxin [PUBMED:10601981, PUBMED:8735594], insect prothoracicotropic hormone (bombyxin) [PUBMED:8683595], insulin-like growth factors (IGF1 and IGF2) [PUBMED:2036417, PUBMED:1319992], mammalian Leydig cell-specific insulin-like peptide (gene INSL3), early placenta insulin-like peptide (ELIP) (gene INSL4), locust insulin-related peptide (LIRP), molluscan insulin-related peptides (MIP), and Caenorhabditis elegans insulin-like peptides. The 3D structures of a number of family members have been determined [PUBMED:2036417, PUBMED:1319992, PUBMED:9141131]. The fold comprises two polypeptide chains (A and B) linked by two disulphide bonds: all share a conserved arrangement of 4 cysteines in their A chain, the first of which is linked by a disulphide bond to the third, while the second and fourth are linked by interchain disulphide bonds to cysteines in the B chain.
Insulin is found in many animals, and is involved in the regulation of normal glucose homeostasis. It also has other specific physiological effects, such as increasing the permeability of cells to monosaccharides, amino acids and fatty acids, and accelerating glycolysis and glycogen synthesis in the liver [PUBMED:6243748]. Insulin exerts its effects by interaction with a cell-surface receptor, which may also result in the promotion of cell growth [PUBMED:6243748].
Insulin is synthesised as a prepropeptide from which an endoplasmic reticulum-targeting sequence is cleaved to yield proinsulin. The sequence of prosinsulin contains 2 well-conserved regions (designated A and B), separated by an intervening connecting region (C), which is variable between species [PUBMED:503234]. The connecting region is cleaved, liberating the active protein, which contains the A and B chains, held together by 2 disulphide bonds [PUBMED:503234].
This entry represents a disulphide-rich alpha-helical domain found in insulin [PUBMED:12595704], as well as in related proteins, such as insulin-like growth factor [PUBMED:15642270], relaxin [PUBMED:1656049] and bombyxin [PUBMED:7473749].
Gene Ontology
The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.
| Cellular component | extracellular region (GO:0005576) |
| Molecular function | hormone activity (GO:0005179) |
Domain organisation
Below is a listing of the unique domain organisations or architectures in which this domain is found. More...
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Pfam Clan
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...
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 (28) |
Full (1447) |
Representative proteomes | NCBI (1711) |
Meta (0) |
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| RP15 (102) |
RP35 (130) |
RP55 (226) |
RP75 (373) |
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| Jalview | ||||||||
| HTML | ||||||||
| PP/heatmap | 1 | |||||||
| Pfam viewer | ||||||||
1Cannot generate PP/Heatmap alignments for seeds; no PP data available
Key:
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Format an alignment
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 (28) |
Full (1447) |
Representative proteomes | NCBI (1711) |
Meta (0) |
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|---|---|---|---|---|---|---|---|---|
| RP15 (102) |
RP35 (130) |
RP55 (226) |
RP75 (373) |
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| Raw Stockholm | ||||||||
| Gzipped | ||||||||
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: | Overington enriched |
| Previous IDs: | ins; |
| Type: | Domain |
| Author: | Eddy SR |
| Number in seed: | 28 |
| Number in full: | 1447 |
| Average length of the domain: | 62.30 aa |
| Average identity of full alignment: | 31 % |
| Average coverage of the sequence by the domain: | 56.65 % |
HMM information
| HMM build commands: |
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
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| Model details: |
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| Model length: | 85 | ||||||||||||
| Family (HMM) version: | 13 | ||||||||||||
| Download: | download the raw HMM for this family |
Species distribution
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Interactions
Structures
For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the Insulin domain has been found. There are 923 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.
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Archea
Eukaryota
Bacteria
Other sequences
Viruses
Unclassified
Viroids
Unclassified sequence