Steroline
Sterolin-1, ABCG5 | ||
---|---|---|
Properties of human protein | ||
Mass / length primary structure | 651 amino acids | |
Secondary to quaternary structure | multipass membrane protein, heterodimer | |
Identifier | ||
Gene name | ABCG5 | |
External IDs | ||
Transporter classification | ||
TCDB | 3.A.1.204.5 | |
designation | ABC transporter |
Sterolin-2, ABCG8 | ||
---|---|---|
Properties of human protein | ||
Mass / length primary structure | 673 amino acids | |
Secondary to quaternary structure | multipass membrane protein, heterodimer | |
Isoforms | 2 | |
Identifier | ||
Gene name | ABCG8 | |
External IDs | ||
Transporter classification | ||
TCDB | 3.A.1.204.5 | |
designation | ABC transporter |
Sterolin (ABCG5 / G8 efflux pump) is the cell membrane - protein , which in mammals excess cholesterol and phytosterols from liver cells pumps out, after which these substances in the gallbladder flow. To a lesser extent, steroline is found in the membrane of enterocytes of the intestine . The energy for the pumping process is provided by ATP . Sterolin is therefore a membrane-bound ATPase , more precisely an ABC transporter .
Steroline is a heterodimer made up of the two semi-transporters ABCG5 and ABCG8. Mutations in either of the two genes can impair the function of sterolins and lead to (rare, hereditary) sitosterinemia . Other mutations increase pump activity and lead to an increased risk of gallstones (GBD4).
The transport equation for ABC transporters (Efflux):
- Substrate (inside) + ATP ⇒ substrate (outside) + ADP + P i
In a study with Chileans, a variant of ABCG5 was associated with hypercholesterolemia . A Taiwanese study showed a similar association with a variant of ABCG8.
Individual evidence
- ↑ Kidambi S, Patel SB: Cholesterol and non-cholesterol sterol transporters: ABCG5, ABCG8 and NPC1L1: a review . In: Xenobiotica . 38, No. 7-8, July 2008, pp. 1119-39. doi : 10.1080 / 00498250802007930 . PMID 18668442 .
- ↑ UniProt Q9H222 , UniProt Q9H221
- ↑ Caamaño JM, Pacheco A, Lanas F, Salazar LA: Single nucleotide polymorphisms in ABCG5 and ABCG8 genes in Chilean subjects with polygenic hypercholesterolemia and controls . In: Clin. Chem. Lab. Med. . 46, No. 11, 2008, pp. 1581-5. doi : 10.1515 / CCLM.2008.311 . PMID 19012522 .
- ↑ Chen ZC, Shin SJ, Kuo KK, Lin KD, Yu ML, Hsiao PJ: Significant association of ABCG8: D19H gene polymorphism with hypercholesterolemia and insulin resistance . In: J. Hum. Genet. . 53, No. 8, 2008, pp. 757-63. doi : 10.1007 / s10038-008-0310-2 . PMID 18581044 .
- ↑ Rudkowska I, Jones PJ: Polymorphisms in ABCG5 / G8 transporters linked to hypercholesterolemia and gallstone disease . In: Nutr. Rev. . 66, No. 6, June 2008, pp. 343-8. doi : 10.1111 / j.1753-4887.2008.00042.x . PMID 18522623 .
Web links
- D'Eustachio / Jassal / reactome.org: ABCG5: ABCG8-mediated export of cholesterol and phytosterols