Summary: Apolipoprotein C-II
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This is the Wikipedia entry entitled "Apolipoprotein C2". More...
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Apolipoprotein C2 Edit Wikipedia article
PDB rendering based on 1by6.
|nmr structure of human apolipoprotein c-ii in the presence of sds|
The protein encoded by this gene is secreted in plasma where it is a component of very low density lipoproteins and chylomicrons. This protein activates the enzyme lipoprotein lipase in capillaries, which hydrolyzes triglycerides and thus provides free fatty acids for cells. Mutations in this gene cause hyperlipoproteinemia type IB, characterized by xanthomas, pancreatitis, and hepatosplenomegaly, but no increased risk for atherosclerosis. Lab tests will show elevated blood levels of triglycerides, cholesterol, and chylomicrons
 Interactive pathway map
Click on genes, proteins and metabolites below to link to respective articles. [§ 1]
- The interactive pathway map can be edited at WikiPathways: "Statin_Pathway_WP430". http://www.wikipathways.org/index.php/Pathway:WP430.
 See also
- Kim SY, Park SM, Lee ST (2006). "Apolipoprotein C-II is a novel substrate for matrix metalloproteinases". Biochem. Biophys. Res. Commun. 339 (1): 47–54. doi:10.1016/j.bbrc.2005.10.182. PMID 16314153.
- "Entrez Gene: APOC2 apolipoprotein C-II". http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=344.
- Jackson RL, Baker HN, Gilliam EB, Gotto AM (1977). "Primary structure of very low density apolipoprotein C-II of human plasma.". Proc. Natl. Acad. Sci. U.S.A. 74 (5): 1942–5. doi:10.1073/pnas.74.5.1942. PMC 431048. PMID 194244. //www.ncbi.nlm.nih.gov/pmc/articles/PMC431048/.
- Lycksell PO, Ohman A, Bengtsson-Olivecrona G, et al. (1992). "Sequence specific 1H-NMR assignments and secondary structure of a carboxy-terminal functional fragment of apolipoprotein CII.". Eur. J. Biochem. 205 (1): 223–31. doi:10.1111/j.1432-1033.1992.tb16772.x. PMID 1555583.
- Hegele RA, Connelly PW, Maguire GF, et al. (1992). "An apolipoprotein CII mutation, CIILys19----Thr' identified in patients with hyperlipidemia.". Dis. Markers 9 (2): 73–80. PMID 1782747.
- Crecchio C, Capurso A, Pepe G (1990). "Identification of the mutation responsible for a case of plasmatic apolipoprotein CII deficiency (Apo CII-Bari).". Biochem. Biophys. Res. Commun. 168 (3): 1118–27. doi:10.1016/0006-291X(90)91145-I. PMID 1971748.
- Bengtsson-Olivecrona G, Sletten K (1990). "Primary structure of the bovine analogues to human apolipoproteins CII and CIII. Studies on isoforms and evidence for proteolytic processing.". Eur. J. Biochem. 192 (2): 515–21. doi:10.1111/j.1432-1033.1990.tb19255.x. PMID 2209608.
- Wei CF, Tsao YK, Robberson DL, et al. (1986). "The structure of the human apolipoprotein C-II gene. Electron microscopic analysis of RNA:DNA hybrids, complete nucleotide sequence, and identification of 5' homologous sequences among apolipoprotein genes.". J. Biol. Chem. 260 (28): 15211–21. PMID 2415514.
- Fojo SS, Lohse P, Parrott C, et al. (1989). "A nonsense mutation in the apolipoprotein C-IIPadova gene in a patient with apolipoprotein C-II deficiency.". J. Clin. Invest. 84 (4): 1215–9. doi:10.1172/JCI114287. PMC 329780. PMID 2477392. //www.ncbi.nlm.nih.gov/pmc/articles/PMC329780/.
- Jackson CL, Bruns GA, Breslow JL (1986). "Isolation of cDNA and genomic clones for apolipoprotein C-II". Meth. Enzymol.. Methods in Enzymology 128: 788–800. doi:10.1016/0076-6879(86)28106-9. ISBN 9780121820282. PMID 3014272.
- Fojo SS, Law SW, Brewer HB (1987). "The human preproapolipoprotein C-II gene. Complete nucleic acid sequence and genomic organization". FEBS Lett. 213 (1): 221–6. doi:10.1016/0014-5793(87)81495-3. PMID 3030808.
- Fojo SS, Stalenhoef AF, Marr K, et al. (1989). "A deletion mutation in the ApoC-II gene (ApoC-II Nijmegen) of a patient with a deficiency of apolipoprotein C-II". J. Biol. Chem. 263 (34): 17913–6. PMID 3192518.
- Fojo SS, Beisiegel U, Beil U, et al. (1988). "Donor splice site mutation in the apolipoprotein (Apo) C-II gene (Apo C-IIHamburg) of a patient with Apo C-II deficiency". J. Clin. Invest. 82 (5): 1489–94. doi:10.1172/JCI113756. PMC 442713. PMID 3263393. //www.ncbi.nlm.nih.gov/pmc/articles/PMC442713/.
- Connelly PW, Maguire GF, Hofmann T, Little JA (1987). "Structure of apolipoprotein C-IIToronto, a nonfunctional human apolipoprotein". Proc. Natl. Acad. Sci. U.S.A. 84 (1): 270–3. doi:10.1073/pnas.84.1.270. PMC 304185. PMID 3467353. //www.ncbi.nlm.nih.gov/pmc/articles/PMC304185/.
- Fairwell T, Hospattankar AV, Brewer HB, Khan SA (1987). "Human plasma apolipoprotein C-II: total solid-phase synthesis and chemical and biological characterization". Proc. Natl. Acad. Sci. U.S.A. 84 (14): 4796–800. doi:10.1073/pnas.84.14.4796. PMC 305192. PMID 3474626. //www.ncbi.nlm.nih.gov/pmc/articles/PMC305192/.
- Fojo SS, Taam L, Fairwell T, et al. (1986). "Human preproapolipoprotein C-II. Analysis of major plasma isoforms". J. Biol. Chem. 261 (21): 9591–4. PMID 3525527.
- Das HK, Jackson CL, Miller DA, et al. (1987). "The human apolipoprotein C-II gene sequence contains a novel chromosome 19-specific minisatellite in its third intron". J. Biol. Chem. 262 (10): 4787–93. PMID 3558370.
- Connelly PW, Maguire GF, Little JA (1988). "Apolipoprotein CIISt. Michael. Familial apolipoprotein CII deficiency associated with premature vascular disease". J. Clin. Invest. 80 (6): 1597–606. doi:10.1172/JCI113246. PMC 442428. PMID 3680515. //www.ncbi.nlm.nih.gov/pmc/articles/PMC442428/.
- Baggio G, Manzato E, Gabelli C, et al. (1986). "Apolipoprotein C-II deficiency syndrome. Clinical features, lipoprotein characterization, lipase activity, and correction of hypertriglyceridemia after apolipoprotein C-II administration in two affected patients". J. Clin. Invest. 77 (2): 520–7. doi:10.1172/JCI112332. PMC 423374. PMID 3944267. //www.ncbi.nlm.nih.gov/pmc/articles/PMC423374/.
- Menzel HJ, Kane JP, Malloy MJ, Havel RJ (1986). "A variant primary structure of apolipoprotein C-II in individuals of African descent". J. Clin. Invest. 77 (2): 595–601. doi:10.1172/JCI112342. PMC 423392. PMID 3944271. //www.ncbi.nlm.nih.gov/pmc/articles/PMC423392/.
- Sharpe CR, Sidoli A, Shelley CS, et al. (1984). "Human apolipoproteins AI, AII, CII and CIII. cDNA sequences and mRNA abundance". Nucleic Acids Res. 12 (9): 3917–32. doi:10.1093/nar/12.9.3917. PMC 318799. PMID 6328445. //www.ncbi.nlm.nih.gov/pmc/articles/PMC318799/.
- Jackson CL, Bruns GA, Breslow JL (1984). "Isolation and sequence of a human apolipoprotein CII cDNA clone and its use to isolate and map to human chromosome 19 the gene for apolipoprotein CII". Proc. Natl. Acad. Sci. U.S.A. 81 (10): 2945–9. doi:10.1073/pnas.81.10.2945. PMC 345197. PMID 6328478. //www.ncbi.nlm.nih.gov/pmc/articles/PMC345197/.
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.
Apolipoprotein C-II Provide feedback
Apolipoprotein C-II (ApoC-II) is the major activator of lipoprotein lipase, a key enzyme in the regulation of triglyceride levels in human serum .
Storjohann R, Rozek A, Sparrow JT, Cushley RJ; , Biochim Biophys Acta 2000;1486:253-264.: Structure of a biologically active fragment of human serum apolipoprotein C-II in the presence of sodium dodecyl sulfate and dodecylphosphocholine. PUBMED:10903476 EPMC:10903476
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR008019
Apolipoprotein CII (apoC-II) is a surface constituent of plasma lipoproteins and the activator for lipoprotein lipase (LPL). It is therefore central for lipid transport in blood. Lipoprotein lipase is a key enzyme in the regulation of triglyceride levels in human serum [PUBMED:10903476]. It is the C-terminal helix of apoC-II that is responsible for the activation of LPL [PUBMED:12590574]. The active peptide of apoC-II occurs at residues 44-79 and has been shown to reverse the symptoms of genetic apoC-II deficiency in a human subject [PUBMED:10903476].
Micellar SDS, a commonly used mimetic of the lipoprotein surface, inhibits the aggregation of apoC-II and induces a stable structure containing approximately 60% alpha-helix. The first 12 residues of apoC-II are structurally heterogeneous but the rest of the protein forms a predominantly helical structure [PUBMED:11331005].
The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.
|Cellular component||chylomicron (GO:0042627)|
|Molecular function||enzyme activator activity (GO:0008047)|
|Biological process||lipid transport (GO:0006869)|
|lipid metabolic process (GO:0006629)|
Below is a listing of the unique domain organisations or architectures in which this domain is found. More...
The graphic that is shown by default represents the longest sequence with a given architecture. Each row contains the following information:
- the number of sequences which exhibit this architecture
a textual description of the architecture, e.g. Gla, EGF x 2, Trypsin.
This example describes an architecture with one
Gladomain, followed by two consecutive
EGFdomains, and finally a single
- a link to the page in the Pfam site showing information about the sequence that the graphic describes
- the UniProt description of the protein sequence
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Note that you can see the family page for a particular domain by clicking on the graphic. You can also choose to see all sequences which have a given architecture by clicking on the Show link in each row.
Finally, because some families can be found in a very large number of architectures, we load only the first fifty architectures by default. If you want to see more architectures, click the button at the bottom of the page to load the next set.
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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.
We make a range of alignments for each Pfam-A family:
- the curated alignment from which the HMM for the family is built
- the alignment generated by searching the sequence database using the HMM
- Representative Proteomes (RPs) at 15%, 35%, 55% and 75% co-membership thresholds
- alignment generated by searching the NCBI sequence database using the family HMM
- alignment generated by searching the metagenomics sequence database using the family HMM
You can see the alignments as HTML or in three different sequence viewers:
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- an HTML-based viewer that uses DAS to retrieve alignment fragments on request
You can download (or view in your browser) a text representation of a Pfam alignment in various formats:
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.
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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.
1Cannot generate PP/Heatmap alignments for seeds; no PP data available
Key: available, not generated, — not available.
Format an alignment
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.
You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.
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 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...
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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.
|Seed source:||Pfam-B_6456 (release 7.8)|
|Number in seed:||6|
|Number in full:||40|
|Average length of the domain:||73.00 aa|
|Average identity of full alignment:||46 %|
|Average coverage of the sequence by the domain:||75.96 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||6|
|Download:||download the raw HMM for this family|
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This visualisation provides a simple graphical representation of the distribution of this family across species. You can find the original interactive tree in the 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:
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".
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.
The tree shows the occurrence of this domain across different species. More...
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.
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
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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.
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 Apo-CII domain has been found. There are 4 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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