ABCG1 p.Tyr649Leu
| Predicted by SNAP2: | A: D (53%), C: N (72%), D: D (75%), E: D (63%), F: N (57%), G: N (53%), H: N (61%), I: N (53%), K: D (71%), L: N (66%), M: N (66%), N: D (63%), P: D (75%), Q: D (59%), R: D (63%), S: N (57%), T: N (53%), V: N (72%), W: N (61%), |
| Predicted by PROVEAN: | A: D, C: D, D: D, E: D, F: N, G: D, H: D, I: D, K: D, L: D, M: D, N: D, P: D, Q: D, R: D, S: D, T: D, V: D, W: N, |
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[hide] Cholesterol sensing by the ABCG1 lipid transporter... Biochim Biophys Acta. 2015 Jul;1851(7):956-64. doi: 10.1016/j.bbalip.2015.02.016. Epub 2015 Feb 27. Sharpe LJ, Rao G, Jones PM, Glancey E, Aleidi SM, George AM, Brown AJ, Gelissen IC
Cholesterol sensing by the ABCG1 lipid transporter: Requirement of a CRAC motif in the final transmembrane domain.
Biochim Biophys Acta. 2015 Jul;1851(7):956-64. doi: 10.1016/j.bbalip.2015.02.016. Epub 2015 Feb 27., [PMID:25732853]
Abstract [show]
The ATP-binding cassette (ABC) transporter, ABCG1, is a lipid exporter involved in removal of cholesterol from cells that has been investigated for its role in foam cells formation and atherosclerosis. The mechanism by which ABC lipid transporters bind and recognise their substrates is currently unknown. In this study, we identify a critical region in the final transmembrane domain of ABCG1, which is essential for its export function and stabilisation by cholesterol, a post-translational regulatory mechanism that we have recently identified as dependent on protein ubiquitination. This transmembrane region contains several Cholesterol Recognition/interaction Amino acid Consensus (CRAC) motifs, and its inverse CARC motifs. Mutational analyses identify one CRAC motif in particular with Y667 at its core, that is especially important for transport activity to HDL as well as stability of the protein in the presence of cholesterol. In addition, we present a model of how cholesterol docks to this CRAC motif in an energetically favourable manner. This study identifies for the first time how ABCG1 can interact with cholesterol via a functional CRAC domain, which provides the first insight into the substrate-transporter interaction of an ABC lipid exporter.
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No. Sentence Comment
147 Individual point mutations of Y649L, Y667L and Y672L were introduced into ABCG1 and stable cell lines overexpressing the individual mutants generated.
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ABCG1 p.Tyr649Leu 25732853:147:30
status: NEW148 Fig. 3A shows that the activity of both the Y649L and Y667L mutants was totally abolished, while the Y672L mutant had reduced cholesterol export activity (this latter difference was not statistically significant).
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ABCG1 p.Tyr649Leu 25732853:148:44
status: NEW151 The Y649L and Y672L mutant proteins however, were consistently stabilised by the addition of cholesterol, suggesting that their cholesterol "sensing" ability was still intact, despite having reduced or negligible cholesterol export capacity.
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ABCG1 p.Tyr649Leu 25732853:151:4
status: NEW163 This may explain why the Y649L mutation inhibited the cholesterol transport activity of ABCG1 without affecting its stabilisation by cholesterol.
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ABCG1 p.Tyr649Leu 25732853:163:25
status: NEW174 2A) Cholesterol export of parental CHOK1 cells (CHOK1), CHOK1 cells overexpressing wild-type ABCG1 (ABCG1), or two independent clones overexpressing triple Y649L, Y667L and Y672L mutants (Triple Y/L).
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ABCG1 p.Tyr649Leu 25732853:174:156
status: NEW203 3A) Cholesterol export of CHOK1 cells overexpressing ABCG1 with a single mutation (Y649L, Y667L or Y672L).
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ABCG1 p.Tyr649Leu 25732853:203:83
status: NEW205 Statistically significant differences in HDL-mediated export (via 2-way ANOVA; p b 0.05) are indicated between cells overexpressing ABCG1 vs CHOK1, Y649L and Y667L mutants.
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ABCG1 p.Tyr649Leu 25732853:205:148
status: NEW