Contents

Apolipoprotein C-I

Protein-coding gene in the species Homo sapiens

APOC1
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 1ALE, 1ALF, 1IOJ, 1OPP
Identifiers
Aliases	APOC1, Apo-CI, ApoC-I, apo-CIB, apoC-IB, apolipoprotein C1, Apolipoprotein C-I
External IDs	OMIM: 107710; MGI: 88053; HomoloGene: 136749; GeneCards: APOC1; OMA:APOC1 - orthologs
Gene location (Human) Chr. Chromosome 19 (human)[1] Band 19q13.32 Start 44,914,247 bp[1] End 44,919,349 bp[1]
Gene location (Mouse) Chr. Chromosome 7 (mouse)[2] Band 7 A3|7 9.94 cM Start 19,423,406 bp[2] End 19,426,585 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in right lobe of liver left adrenal cortex right adrenal cortex nucleus accumbens putamen caudate nucleus right lung spleen substantia nigra hypothalamus Top expressed in left lobe of liver gallbladder lip blastocyst brown adipose tissue skin of external ear yolk sac transitional epithelium of urinary bladder esophagus tunica adventitia of aorta More reference expression data BioGPS n/a
Gene ontology Molecular function phospholipase inhibitor activity lipase inhibitor activity phosphatidylcholine binding fatty acid binding phosphatidylcholine-sterol O-acyltransferase activator activity Cellular component chylomicron very-low-density lipoprotein particle endoplasmic reticulum high-density lipoprotein particle extracellular region Biological process lipid transport chylomicron remnant clearance negative regulation of fatty acid biosynthetic process lipid metabolism positive regulation of cholesterol esterification phospholipid efflux cholesterol metabolic process negative regulation of phosphatidylcholine catabolic process plasma lipoprotein particle remodeling negative regulation of very-low-density lipoprotein particle clearance regulation of cholesterol transport negative regulation of receptor-mediated endocytosis high-density lipoprotein particle remodeling cholesterol efflux negative regulation of cholesterol transport negative regulation of lipoprotein lipase activity very-low-density lipoprotein particle assembly negative regulation of lipid catabolic process triglyceride metabolic process negative regulation of lipid metabolic process positive regulation of catalytic activity very-low-density lipoprotein particle clearance lipoprotein metabolic process Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 341 11812 Ensembl ENSG00000130208 ENSMUSG00000040564 UniProt P02654 P34928 RefSeq (mRNA) NM_001645 NM_001321065 NM_001321066 NM_001379687 NM_001110009 NM_007469 RefSeq (protein) NP_001307994 NP_001307995 NP_001636 NP_001366616 NP_001103479 NP_031495 Location (UCSC) Chr 19: 44.91 – 44.92 Mb Chr 7: 19.42 – 19.43 Mb PubMed search [3] [4]
Wikidata
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ApoC-I
structural studies of a baboon (papio sp.) plasma protein inhibitor of cholesteryl ester transferase.
Identifiers
Symbol	ApoC-I
Pfam	PF04691
InterPro	IPR006781
SCOP2	1ale / SCOPe / SUPFAM
Available protein structures: Pfam   structures / ECOD   PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

Apolipoprotein C-I is a protein component of lipoproteins that in humans is encoded by the APOC1 gene.^[5][6]

Function[edit]

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. Alternatively spliced transcript variants have been found for this gene, but the biological validity of some variants has not been determined.^[7]

Apolipoprotein C-I has a length of 57 amino acids normally found in plasma and responsible for the activation of esterified lecithin 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 cholesteryl ester transfer protein (CETP), probably by altering the electric chargeofHDL molecules.

During fasting (like other apolipoproteinC), 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.

Pseudogene[edit]

Apseudogene of this gene is located 4 kb downstream from the apoC-I gene in the same orientation on chromosome 19, where both reside within an apolipoprotein gene cluster. This pseudogene, which was also reported to have been present in Denisovans and Neandertals, originated from two separate events. Following the divergence of New World monkeys from the human lineage, the apoC-I gene was duplicated. Old World monkeys and great apes other than humans have been shown to have two active genes. One of the duplicates encodes a basic protein designated apoC-IB that is orthologous to human apolipoprotein C-I. The other encodes an acidic protein, apoC-IA, that is orthologous to the virtual protein encoded by the pseudogene. The pseudogenization event occurred sometime between the divergence of bonobos and chimpanzees from the human lineage and the arrival of Denisovans and Neandertals. The pseudogene is due to a change in a single nucleotide in the codon for the penultimate amino acid, i.e. glutamine, in the signal sequence, resulting in a stop codon.^[8][9][10]

Interactive pathway map[edit]

Click on genes, proteins and metabolites below to link to respective articles. ^{[§ 1]}

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References[edit]

Further reading[edit]

External links[edit]

• Human APOC1 genome location and APOC1 gene details page in the UCSC Genome Browser.
• PDBe-KB provides an overview of all the structure information available in the PDB for Human Apolipoprotein C-I

This article on a gene on human chromosome 19 is a stub. You can help Wikipedia by expanding it.