Summary: Apolipoprotein C-I (ApoC-1)
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This is the Wikipedia entry entitled "Apolipoprotein C1". More...
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Apolipoprotein C1 Edit Wikipedia article
PDB rendering based on 1ioj.
structural studies of a baboon (papio sp.) plasma protein inhibitor of cholesteryl ester transferase.
The protein encoded by this gene is a member of the apolipoprotein C family. This gene is expressed primarily in the liver, and it is activated when monocytes differentiate into macrophages. A pseudogene of this gene is located 4 kb downstream in the same orientation, on the same chromosome. This gene is mapped to chromosome 19, where it resides within an apolipoprotein gene cluster. Alternatively spliced transcript variants have been found for this gene, but the biological validity of some variants has not been determined.
Apolipoprotein C1 has a length of 57 amino acids normally found in plasma and responsible for the activation of esterified lechitin cholesterol with an important role in the exchange of esterified cholesterol between lipoproteins and in removal of cholesterol from tissues. Its main function is inhibition of CETP, probably by altering the electric charge of HDL molecules.
During fasting (like other apolipoprotein C), it is found primarily within HDL, while after a meal it is found on the surface of other lipoproteins. When proteins rich in triglycerides like chylomicrons and VLDL are broken down, this apoprotein is transferred again to HDL. It is one of the most positively charged proteins in the human body.
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".
- Tata F, Henry I, Markham AF, Wallis SC, Weil D, Grzeschik KH, Junien C, Williamson R, Humphries SE (1985). "Isolation and characterisation of a cDNA clone for human apolipoprotein CI and assignment of the gene to chromosome 19". Hum. Genet. 69 (4): 345–9. doi:10.1007/BF00291654. PMID 2985493.
- Smit M, van der Kooij-Meijs E, Frants RR, Havekes L, Klasen EC (January 1988). "Apolipoprotein gene cluster on chromosome 19. Definite localization of the APOC2 gene and the polymorphic Hpa I site associated with type III hyperlipoproteinemia". Hum. Genet. 78 (1): 90–3. doi:10.1007/BF00291243. PMID 2892779.
- "Entrez Gene: APOC1 apolipoprotein C-I".
- Shulman RS, Herbert PN, Wehrly K, Fredrickson DS (1975). "Thf complete amino acid sequence of C-I (apoLp-Ser), an apolipoprotein from human very low density lipoproteins". J. Biol. Chem. 250 (1): 182–90. PMID 166984.
- Lauer SJ, Walker D, Elshourbagy NA, et al. (1988). "Two copies of the human apolipoprotein C-I gene are linked closely to the apolipoprotein E gene". J. Biol. Chem. 263 (15): 7277–86. PMID 2835369.
- Smit M, van der Kooij-Meijs E, Woudt LP, et al. (1988). "Exact localization of the familial dysbetalipoproteinemia associated HpaI restriction site in the promoter region of the APOC1 gene". Biochem. Biophys. Res. Commun. 152 (3): 1282–8. doi:10.1016/S0006-291X(88)80424-8. PMID 2897845.
- Davison PJ, Norton P, Wallis SC, et al. (1986). "There are two gene sequences for human apolipoprotein CI (apo CI) on chromosome 19, one of which is 4 kb from the gene for apo E". Biochem. Biophys. Res. Commun. 136 (3): 876–84. doi:10.1016/0006-291X(86)90414-6. PMID 3013172.
- Myklebost O, Rogne S (1986). "The gene for human apolipoprotein CI is located 4.3 kilobases away from the apolipoprotein E gene on chromosome 19". Hum. Genet. 73 (4): 286–9. doi:10.1007/BF00279087. PMID 3017837.
- Jackson RL, Sparrow JT, Baker HN, et al. (1974). "The primary structure of apolopoprotein-serine". J. Biol. Chem. 249 (16): 5308–13. PMID 4369340.
- Knott TJ, Robertson ME, Priestley LM, et al. (1984). "Characterisation of mRNAs encoding the precursor for human apolipoprotein CI". Nucleic Acids Res. 12 (9): 3909–15. doi:10.1093/nar/12.9.3909. PMC 318798. PMID 6328444.
- Servillo L, Brewer HB, Osborne JC (1981). "Evaluation of the mixed interaction between apolipoproteins A-II and C-I equilibrium sedimentation". Biophys. Chem. 13 (1): 29–38. doi:10.1016/0301-4622(81)80022-1. PMID 6789904.
- Curry MD, McConathy WJ, Fesmire JD, Alaupovic P (1981). "Quantitative determination of apolipoproteins C-I and C-II in human plasma by separate electroimmunoassays". Clin. Chem. 27 (4): 543–8. PMID 7471419.
- Rozek A, Buchko GW, Cushley RJ (1995). "Conformation of two peptides corresponding to human apolipoprotein C-I residues 7-24 and 35-53 in the presence of sodium dodecyl sulfate by CD and NMR spectroscopy". Biochemistry 34 (22): 7401–8. doi:10.1021/bi00022a013. PMID 7779782.
- Maruyama K, Sugano S (1994). "Oligo-capping: a simple method to replace the cap structure of eukaryotic mRNAs with oligoribonucleotides". Gene 138 (1–2): 171–4. doi:10.1016/0378-1119(94)90802-8. PMID 8125298.
- Trask B, Fertitta A, Christensen M, et al. (1993). "Fluorescence in situ hybridization mapping of human chromosome 19: cytogenetic band location of 540 cosmids and 70 genes or DNA markers". Genomics 15 (1): 133–45. doi:10.1006/geno.1993.1021. PMID 8432525.
- Kamino K, Yoshiiwa A, Nishiwaki Y, et al. (1996). "Genetic association study between senile dementia of Alzheimer's type and APOE/C1/C2 gene cluster". Gerontology. 42 Suppl 1: 12–9. doi:10.1159/000213820. PMID 8804993.
- Rozek A, Buchko GW, Kanda P, Cushley RJ (1998). "Conformational studies of the N-terminal lipid-associating domain of human apolipoprotein C-I by CD and 1H NMR spectroscopy". Protein Sci. 6 (9): 1858–68. doi:10.1002/pro.5560060906. PMC 2143781. PMID 9300485.
- Suzuki Y, Yoshitomo-Nakagawa K, Maruyama K, et al. (1997). "Construction and characterization of a full length-enriched and a 5'-end-enriched cDNA library". Gene 200 (1–2): 149–56. doi:10.1016/S0378-1119(97)00411-3. PMID 9373149.
- Halushka MK, Fan JB, Bentley K, et al. (1999). "Patterns of single-nucleotide polymorphisms in candidate genes for blood-pressure homeostasis". Nat. Genet. 22 (3): 239–47. doi:10.1038/10297. PMID 10391210.
- Freitas EM, Zhang WJ, Lalonde JP, et al. (1999). "Sequencing of 42kb of the APO E-C2 gene cluster reveals a new gene: PEREC1". DNA Seq. 9 (2): 89–100. doi:10.3109/10425179809086433. PMID 10520737.
- Gautier T, Masson D, de Barros JP, et al. (2001). "Human apolipoprotein C-I accounts for the ability of plasma high density lipoproteins to inhibit the cholesteryl ester transfer protein activity". J. Biol. Chem. 275 (48): 37504–9. doi:10.1074/jbc.M007210200. PMID 10978346.
- 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.
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Apolipoprotein C-I (ApoC-1) Provide feedback
Apolipoprotein C-I (ApoC-1) is a water-soluble protein component of plasma lipoprotein. It solubalises lipids and regulates lipid metabolism. ApoC-1 transfers among HDL (high density lipoprotein), VLDL (very low-density lipoprotein) and chylomicrons. ApoC-1 activates lecithin:choline acetyltransferase (LCAT), inhibits cholesteryl ester transfer protein, can inhibit hepatic lipase and phospholipase 2 and can stimulate cell growth. ApoC-1 delays the clearance of beta-VLDL by inhibiting its uptake via the LDL receptor-related pathway . ApoC-1 has been implicated in hypertriglyceridemia  and Alzheimer's disease .
Petit-Turcotte C, Stohl SM, Beffert U, Cohn JS, Aumont N, Tremblay M, Dea D, Yang L, Poirier J, Shachter NS; , Neurobiol Dis 2001;8:953-963.: Apolipoprotein C-I expression in the brain in Alzheimer's disease. PUBMED:11741391 EPMC:11741391
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR006781
Exchangeable apolipoproteins are water-soluble protein components of lipoproteins that solubilise lipids and regulate their metabolism by binding to cell receptors or activating specific enzymes. Apolipoprotein C-I (ApoC-1) is the smallest exchangeable apolipoprotein and transfers among HDL (high density lipoprotein), VLDL (very low-density lipoprotein) and chlylomicrons. ApoC-1 activates lecithin:choline acetyltransferase (LCAT), inhibits cholesteryl ester transfer protein, can inhibit hepatic lipase and phospholipase 2 and can stimulate cell growth. ApoC-1 delays the clearance of beta-VLDL by inhibiting its uptake via the LDL receptor-related pathway [PUBMED:11580293]. ApoC-1 has been implicated in hypertriglyceridemia [PUBMED:11353333], and Alzheimer s disease [PUBMED:11741391].
ApoC-1 is believed to comprise of two dynamic helices that are stabilised by interhelical interactions and are connected by a short linker region. The minimal folding unit in the lipid-free state of this and other exchangeable apolipoproteins comprises the helix-turn-helix motif formed of four 11-mer sequence repeats.
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)|
|Biological process||lipoprotein metabolic process (GO:0042157)|
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:
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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...
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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.
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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.
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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.
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|Number in seed:||6|
|Number in full:||41|
|Average length of the domain:||55.00 aa|
|Average identity of full alignment:||47 %|
|Average coverage of the sequence by the domain:||71.03 %|
|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:||7|
|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:
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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.
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There are some situations that the sunburst tree cannot easily handle and for which we have work-arounds in place.
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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.
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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.
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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.
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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 ApoC-I domain has been found. There are 5 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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