title: Phosphatidylserine recognition and induction of apoptotic cell clearance by Drosophila engulfment receptor Draper.
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.
authors: Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Ishikawa 920-1192, Japan.
authors: Tran Thanh
authors: TT
authors: Tung
authors: Kaz
authors: K
authors: Nagaosa
authors: Yu
authors: Y
authors: Fujita
authors: Asana
authors: A
authors: Kita
authors: Hiroki
authors: H
authors: Mori
authors: Ryo
authors: R
authors: Okada
authors: Saori
authors: S
authors: Nonaka
authors: Yoshinobu
authors: Y
authors: Nakanishi
mesh_terms: D000217:Acyltransferases; D000818:Animals; D017209:Apoptosis / Q000235:genetics / Q000502:physiology; D004330:Drosophila; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D010587:Phagocytosis / Q000235:genetics / Q000502:physiology; D010718:Phosphatidylserines / Q000378:metabolism*
chemical_list: D029721:Drosophila Proteins; D008565:Membrane Proteins; D010718:Phosphatidylserines; C495322:drpr protein, Drosophila; D000217:Acyltransferases; C022368:phospholipid acyltransferases