Phosphatidylcholine Transfer Protein Promotes Apolipoprotein A-I-mediated Lipid Efflux in Chinese Hamster Ovary Cells

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摘要：

Phosphatidylcholine transfer protein (PC-TP) is a cytosolic protein of unknown function that catalyzes intermembrane transfer of phosphatidylcholines . Using stably transfected CHO cells, we explored the influence of PC-TP on apolipoprotein A-I- and high density lipoprotein 3 (HDL)-mediated lipid efflux. In proportion to its cellular level of expression, PC-TP accelerated apolipoprotein A-I-mediated phospholipid and cholesterol efflux as pre-β-HDL particles. PC-TP increased rates of efflux of both lipids by >2-fold but did not affect mRNA levels or the activity of ATP-binding cassette A1, a plasma membrane protein that regulates apolipoprotein A-I-mediated lipid efflux. Overexpression of PC-TP was associated with only slight increases in HDL-mediated phospholipid efflux and no changes in cholesterol efflux. In scavenger receptor BI-overexpressing cells, PC-TP expression minimally influenced apolipoprotein A-I- or HDL-mediated lipid efflux. PC-TP did not affect cellular phospholipid compositions, phosphatidylcholine contents, or phosphatidylcholine synthetic rates. These findings suggest that a physiological function of PC-TP is to replenish the plasma membrane with phosphatidylcholines that are removed during pre-β-HDL particle formation due to the activity of ATP-binding cassette A1.

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关键词：

Pectobacterium chrysanthemi Cel5Z Cel5Z ::Omega high-level expression CMC-SDS-PAGE

DOI：

10.1074/jbc.M106799200

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年份：

2002