Posttranscriptional regulation of human ABCA7 and its function for the apoA-I-dependent lipid release

  • Biochem Biophys Res Commun. 2003 Nov 14;311(2):313-8. doi: 10.1016/j.bbrc.2003.10.002.
Yuika Ikeda  1 ,  Sumiko Abe-Dohmae ,  Youichi Munehira ,  Ryo Aoki ,  Shinobu Kawamoto ,  Akiko Furuya ,  Kenya Shitara ,  Teruo Amachi ,  Noriyuki Kioka ,  Michinori Matsuo ,  Shinji Yokoyama ,  Kazumitsu Ueda
Affiliations
  • 1. Laboratory of Cellular Biochemistry, Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan.
PMID: 14592415 DOI: 10.1016/j.bbrc.2003.10.002
Abstract

ABCA7 is expressed predominantly in myelo-lymphatic tissues or reticuloendothelial cells. Physiological role and function of this protein are not fully understood. We isolated the full-length cDNA (type I) and a splicing variant cDNA (type II) of human ABCA7, and developed monoclonal antibodies against extracellular domain (ECD)1 of ABCA7. RT-PCR experiments suggested that human ABCA7 gene produced the type II mRNA in a tissue-specific manner. Immunostaining revealed that the type I ABCA7, expressed in HEK293 cells, was localized to the plasma membrane and ECD1 was exposed to the extracellular space as was the case for ABCA1. HEK293 cells expressing type I ABCA7 showed apoA-I-dependent Cholesterol and phospholipid release. In contrast, type II ABCA7 appeared to be localized mainly in endoplasmic reticulum and did not show apoA-I-dependent Cholesterol and phospholipid release. Alternative splicing could be involved in the post-transcriptional regulation of the expression and function of human ABCA7.