ABCMdb

ABCA1 p.Ser1302Ala

Predicted by SNAP2:	A: N (87%), C: N (87%), D: N (72%), E: N (87%), F: N (66%), G: N (82%), H: N (82%), I: N (66%), K: N (87%), L: N (72%), M: N (82%), N: N (87%), P: N (82%), Q: N (87%), R: N (82%), T: N (93%), V: N (78%), W: D (66%), Y: D (53%),
Predicted by PROVEAN:	A: N, C: N, D: N, E: N, F: D, G: N, H: N, I: D, K: N, L: D, M: N, N: N, P: N, Q: N, R: N, T: N, V: N, W: D, Y: D,

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Publications
[hide] Phosphorylation of a pest sequence in ABCA1 promot... J Biol Chem. 2003 Sep 26;278(39):37368-74. Epub 2003 Jul 17. Martinez LO, Agerholm-Larsen B, Wang N, Chen W, Tall AR
Phosphorylation of a pest sequence in ABCA1 promotes calpain degradation and is reversed by ApoA-I.
J Biol Chem. 2003 Sep 26;278(39):37368-74. Epub 2003 Jul 17., [PMID:12869555]

Abstract [show]
ATP-binding cassette transporter A1 (ABCA1), the defective molecule in Tangier disease, mediates the apoAI-dependent efflux of excess cholesterol from cells. We recently showed that ABCA1 proteolysis by calpain was dependent on a PEST sequence in the cytoplasmic region of ABCA1 and was reversed by apoA-I interaction with ABCA1. We show here that phosphorylation of ABCA1 in HEK293 cells was reduced by 63 +/- 2.4% after removal of the PEST sequence (ABCA1delPEST) or by incubation of cells with apoAI (58 +/- 3.3%). By contrast, ABCA1delPEST showed no further decrease of phosphorylation upon apoAI treatment. To assess the hypothesis that PEST sequence phosphorylation could regulate ABCA1 calpain proteolysis, we mutagenized S/T residues in the PEST sequence and identified Thr-1286 and Thr-1305 as constitutively phosphorylated residues. The ABCA1-T1286A/T1305A mutant was not degraded by calpain and was not further stabilized upon apoA-I treatment. The T1286A/T1305A mutant showed a 3.1-fold increase in cell surface expression and a 2.3-fold increase of apoAI-mediated cholesterol efflux compared with wild type ABCA1. In conclusion, we propose a mechanism of regulation of ABCA1 cell surface expression and function in which the interaction with apoA-I results in dephosphorylation of the ABCA1 PEST sequence and thereby inhibits calpain degradation leading to an increase of ABCA1 cell surface expression.

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31 mABCA1-FLAG mutation constructs were further called: MutAAAA for mutation to Ala on T1286A/S1296A/S1302A/T1305A, MutTAAT for mutation to Ala on S1296A/S1302A, and MutASSA for mutation to Ala on * This work was supported in part by National Institutes of Health Grant HL22682. Login to comment
121 Mutation of Thr residues (1286 and 1305) decreases ABCA1 Phosphorylation. WT-mABCA1-FLAG, mABCA1delPEST-FLAG, mABCA1-FLAG mutated to Ala on T1286A/S1296A/S1302A/T1305A (MutAAAA), mutated to Ala on S1296A/S1302A (MutTAAT), or mutated to Ala on T1286A/T1305A (MutASSA), were transiently transfected in 6 wells of HEK-293 cells (2 ␮g of plasmid DNA per well). Login to comment
30 mABCA1-FLAG mutation constructs were further called: MutAAAA for mutation to Ala on T1286A/S1296A/S1302A/T1305A, MutTAAT for mutation to Ala on S1296A/S1302A, and MutASSA for mutation to Ala on * This work was supported in part by National Institutes of Health Grant HL22682. Login to comment
118 Mutation of Thr residues (1286 and 1305) decreases ABCA1 Phosphorylation. WT-mABCA1-FLAG, mABCA1delPEST-FLAG, mABCA1-FLAG mutated to Ala on T1286A/S1296A/S1302A/T1305A (MutAAAA), mutated to Ala on S1296A/S1302A (MutTAAT), or mutated to Ala on T1286A/T1305A (MutASSA), were transiently transfected in 6 wells of HEK-293 cells (2 òe;g of plasmid DNA per well). Login to comment