Phosphatidylserine recognition and induction of apoptotic cell clearance by Drosophila engulfment receptor Draper

J Biochem. 2013 May;153(5):483-91. doi: 10.1093/jb/mvt014. Epub 2013 Feb 18.

Abstract

The membrane phospholipid phosphatidylserine is exposed on the cell surface during apoptosis and acts as an eat-me signal in the phagocytosis of apoptotic cells in mammals and nematodes. However, whether this is also true in insects was unclear. When milk fat globule-epidermal growth factor 8, a phosphatidylserine-binding protein of mammals, was ectopically expressed in Drosophila, the level of phagocytosis was reduced, whereas this was not the case for the same protein lacking a domain responsible for the binding to phosphatidylserine. We found that the extracellular region of Draper, an engulfment receptor of Drosophila, binds to phosphatidylserine in an enzyme-linked immunosorbent assay-like solid-phase assay and in an assay for surface plasmon resonance. A portion of Draper containing domains EMI and NIM located close to the N-terminus was required for binding to phosphatidylserine, and a Draper protein lacking this region was not active in Drosophila. Finally, the level of tyrosine-phosphorylated Draper, indicative of the activation of Draper, in a hemocyte-derived cell line was increased after treatment with phosphatidylserine-containing liposome. These results indicated that phosphatidylserine serves as an eat-me signal in the phagocytic removal of apoptotic cells in Drosophila and that Draper is a phosphatidylserine-binding receptor for phagocytosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acyltransferases
  • Animals
  • Apoptosis / genetics
  • Apoptosis / physiology
  • Drosophila
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism*
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Phagocytosis / genetics
  • Phagocytosis / physiology
  • Phosphatidylserines / metabolism*

Substances

  • Drosophila Proteins
  • Membrane Proteins
  • Phosphatidylserines
  • drpr protein, Drosophila
  • Acyltransferases
  • phospholipid acyltransferases