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

Krishnakumar Balasubramanian, Banafsheh Mirnikjoo, Alan J. Schroit

Research output: Contribution to journalArticlepeer-review

135 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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