Recent work identified ABCA1 as the major regulator of plasma HDL-cholesterol responsible for the removal of excess choline-phospholipids and cholesterol from peripheral cells and tissues. ABCA1 function may depend on the association with heteromeric proteins and to identify these candidates a human liver yeast two-hybrid library was screened with the carboxyterminal 144 amino acids of ABCA1. Beta2-syntrophin was found to interact with ABCA1 and the C-terminal five amino acids of ABCA1 proned to represent a perfect tail for binding to syntrophin PDZ domains. Immunoprecipitation further confirmed the association of ABCA1 and beta2-syntrophin and in addition utrophin, known to couple beta2-syntrophin and its PDZ ligands to the F-actin cytoskeleton, was identified as a constituent of this complex. ABCA1 in the plasmamembrane of human macrophages was found to be partially associated with Lubrol rafts and effluxed choline-phospholipids involve these microdomains. Beta2-syntrophin does not colocalize in these rafts indicating that beta2-syntrophin may participate in the retaining of ABCA1 in cytoplasmic vesicles and for the targeting of ABCA1 to plasmamembrane microdomains when ABCA1 is released from beta2-syntrophin.
SciCrunch is a data sharing and display platform. Anyone can create a custom portal where they can select searchable subsets of hundreds of data sources, brand their web pages and create their community. SciCrunch will push data updates automatically to all portals on a weekly basis. User communities can also add their own data to SciCrunch, however this is not currently a free service.