ABCMdb

PMID: 21507939

Hozoji-Inada M, Munehira Y, Nagao K, Kioka N, Ueda K
Liver X receptor beta (LXRbeta) interacts directly with ATP-binding cassette A1 (ABCA1) to promote high density lipoprotein formation during acute cholesterol accumulation.
J Biol Chem. 2011 Jun 3;286(22):20117-24. Epub 2011 Apr 20., [PubMed]

Sentences

No. Mutations Sentence Comment

85 ABCA1 p.Glu2254Ala As a control, a construct in which Glu2254 was replaced with alanine was generated. Login to comment 86 ABCA1 p.Glu2254Ala As a control, a construct in which Glu2254 was replaced with alanine was generated. Login to comment 89 ABCA1 p.Leu2251Ala ABCA1 p.Leu2247Ala However, mutation of Leu2247 and Leu2251 to alanine abrogated the co-precipitation of LXRbeta despite comparable levels of expression among these mutants and WT ABCA1. Login to comment 90 ABCA1 p.Leu2251Ala ABCA1 p.Leu2247Ala However, mutation of Leu2247 and Leu2251 to alanine abrogated the co-precipitation of LXRbeta despite comparable levels of expression among these mutants and WT ABCA1. Login to comment 107 ABCA1 p.Leu2251Ala ABCA1 p.Leu2247Ala HEK293 cells stably expressing FLAG-tagged LXRbeta were transfected with HA-tagged WT ABCA1 L2247A mutant or L2251A mutant. Login to comment 108 ABCA1 p.Leu2251Ala ABCA1 p.Leu2247Ala HEK293 cells stably expressing FLAG-tagged LXRbeta were transfected with HA-tagged WT ABCA1 L2247A mutant or L2251A mutant. Login to comment 112 ABCA1 p.Leu2251Ala ABCA1 p.Leu2247Ala When the mutant constructs were expressed in HEK293 cells, L2247A or L2251A substitution did not affect the surface expression of ABCA1, but LXRbeta no longer co-localized with ABCA1 (Fig. 2). Login to comment 113 ABCA1 p.Leu2251Ala ABCA1 p.Leu2247Ala When the mutant constructs were expressed in HEK293 cells, L2247A or L2251A substitution did not affect the surface expression of ABCA1, but LXRbeta no longer co-localized with ABCA1 (Fig. 2). Login to comment 119 ABCA1 p.Leu2251Ala ABCA1 p.Leu2247Ala Interestingly, apoA-I bound to cells expressing L2247A or L2251A mutant ABCA1 even when LXRbeta was co-expressed. Login to comment 120 ABCA1 p.Leu2251Ala ABCA1 p.Leu2247Ala Interestingly, apoA-I bound to cells expressing L2247A or L2251A mutant ABCA1 even when LXRbeta was co-expressed. Login to comment 121 ABCA1 p.Leu2251Ala ABCA1 p.Leu2251Ala ABCA1 p.Leu2247Ala ABCA1 p.Leu2247Ala When ABCA1-L2247A, ABCA1-L2251A, or ABCA1-L2247A/L2251A was expressed alone, cholesterol efflux to apoA-I was comparable with cells expressing WT ABCA1 in the absence or presence of TO901317 (black bars and empty bars, respectively, in Fig. 3B). Login to comment 122 ABCA1 p.Leu2251Ala ABCA1 p.Leu2251Ala ABCA1 p.Leu2247Ala ABCA1 p.Leu2247Ala When ABCA1-L2247A, ABCA1-L2251A, or ABCA1-L2247A/L2251A was expressed alone, cholesterol efflux to apoA-I was comparable with cells expressing WT ABCA1 in the absence or presence of TO901317 (black bars and empty bars, respectively, in Fig. 3B). Login to comment 125 ABCA1 p.Leu2251Ala ABCA1 p.Leu2251Ala ABCA1 p.Leu2247Ala Co-expression of LXRbeta doubled the plasma membrane levels of WT ABCA1 as shown previously (16), but surface levels of the mutants (L2247A, L2251A, and L2247/L2251A) were not affected by LXRbeta expression (Fig. 3C). Login to comment 126 ABCA1 p.Leu2251Ala ABCA1 p.Leu2251Ala ABCA1 p.Leu2247Ala Co-expression of LXRbeta doubled the plasma membrane levels of WT ABCA1 as shown previously (16), but surface levels of the mutants (L2247A, L2251A, and L2247/L2251A) were not affected by LXRbeta expression (Fig. 3C). Login to comment 148 ABCA1 p.Leu2251Ala ABCA1 p.Leu2247Ala ABCA1-L2247A/L2251A double mutant was labeled as efficiently as WT ABCA1 (lane 9), but this was not inhibited by LXRbeta co-expression (lanes 11 and 12), suggesting that the interaction of LXRbeta with ABCA1 via Leu2247 and Leu2251 prevents tight ATP binding. Login to comment 149 ABCA1 p.Leu2251Ala ABCA1 p.Leu2247Ala ABCA1-L2247A/L2251A double mutant was labeled as efficiently as WT ABCA1 (lane 9), but this was not inhibited by LXRbeta co-expression (lanes 11 and 12), suggesting that the interaction of LXRbeta with ABCA1 via Leu2247 and Leu2251 prevents tight ATP binding. Login to comment