Regulated externalization of phosphatidylserine at the cell surface: Implications for apoptosis

Krishnakumar Balasubramanian, Banafsheh Mirnikjoo, Alan J. Schroit

Research output: Contribution to journalArticle

132 Scopus citations

Abstract

The regulated loss of plasma membrane phosphatidylserine (PS) asymmetry is critical to many biological processes. In particular, the appearance of PS at the cell surface, a hallmark of apoptosis, prepares the dying cell for engulfment and elimination by phagocytes. While it is well established that PS externalization is regulated by activation of a calcium-dependent phospholipid scramblase activity in concert with inactivation of the aminophospholipid translocase, there is no evidence indicating that these processes are triggered and regulated by apoptotic regulatory mechanisms. Using a novel model system, we show that PS externalization is inducible, reversible, and independent of cytochrome c release, caspase activation, and DNA fragmentation. Additional evidence is presented indicating that the outward movement of plasma membrane PS requires sustained elevation in cytosolic Ca2+ in concert with inactivation of the aminophospholipid translocase and is inhibited by calcium channel blockers.

Original languageEnglish (US)
Pages (from-to)18357-18364
Number of pages8
JournalJournal of Biological Chemistry
Volume282
Issue number25
DOIs
StatePublished - Jun 22 2007

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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