Specific Mutations in ABCA1 Have Discrete Effects on ABCA1 Function and Lipid Phenotypes Both In Vivo and In Vitro

Abstract

Abstract-Mutations in ATP-binding cassette transporter A1 (ABCA1) cause Tangier disease and familial hypoalphalipoproteinemia, resulting in low to absent plasma high-density lipoprotein cholesterol levels. However, wide variations in clinical lipid phenotypes are observed in patients with mutations in ABCA1. We hypothesized that the various lipid phenotypes would be the direct result of discrete and differing effects of the mutations on ABCA1 function. To determine whether there is a correlation between the mutations and the resulting phenotypes, we generated in vitro 15 missense mutations that have been described in patients with Tangier disease and familial hypoalphalipoproteinemia. Using localization of ABCA1, its ability to induce cell surface binding of apolipoprotein A-I, and its ability to elicit efflux of cholesterol and phospholipids to apolipoprotein A-I we determined that the phenotypes of patients correlate with the severity and nature of defects in ABCA1 function. (Circ Res. 2006;99:389-397.)

Sodium taurocholate-dependent lipid efflux by ABCA1: effects of W590S mutation on lipid translocation and apolipoprotein A-I dissociation

“…The W590S mutation may abolish the coupling of ATP-induced conformational changes of ABCA1 with lipid translocation. The kinetics of apoA-I binding to cells expressing ABCA1-W590S were similar to those of binding to cells expressing wild-type ABCA1, consistent with a previous report showing that the W590S mutation does not impair apoA-I binding (8,(26)(27)(28). Thus, the W590S mutation would not affect the conformational changes of ABCA1 Fig.…”

“…The W590S Tangier mutation impairs NaTC-dependent lipid efflux but not apoA-I binding It has been reported that ABCA1 carrying the Tangier disease mutation W590S in the first extra cellular domain is correctly targeted to the plasma membrane and interacts with apoA-I but fails to mediate normal apoA-I-dependent lipid efflux (3,(26)(27)(28). We compared NaTC-dependent lipid efflux from HEK293 cells stably expressing wild-type or ABCA1-W590S fused to GFP at the C terminus.…”

Targeted next-generation sequencing to diagnose disorders of HDL cholesterol

“…Larger sample sizes and partial loss-of-function alleles, respectively. Similar results have been reported previously for another mutation in ABCA1 (p.Trp590Ser) that affects the same amino acid position ( 22 ).…”

Both STAT3 activation and cholesterol efflux contribute to the anti-inflammatory effect of apoA-I/ABCA1 interaction in macrophages

“…PCR mutagenesis was used to create an ABCA1 mutant library, and mutants were screened for the ability to activate STAT3 and to efflux cholesterol by apoA-I/ABCA1 interaction. For better visualization of ABCA1 expression and sorting, a green fluorescent protein tag was added to the C terminal of ABCA1, and this does not affect ABCA1 function (35)(36)(37).…”