Editors' ChoicePhagocytosis

Eating the Dead

Science's STKE  14 May 2002:
Vol. 2002, Issue 132, pp. tw172
DOI: 10.1126/stke.2002.132.tw172

Phagocytes identify and engulf apoptotic cells, but the molecular details of this recognition process have not been clear. Hanayama et al. report that macrophages secrete a glycoprotein called milk fat globule-EGF-factor 8 (MFG-E8) that recognizes phophatidylserine and phosphatidylethanolamine. These aminophospholipids flip to the outer leaflet of the plasma membrane when cells undergo apoptosis. Purified recombinant MFG-E8 bound only to apoptotic thymocytes and not to healthy counterparts. MGF-E8 also bears an RGD motif that binds to integrins present at the surface of macrophages, thereby providing a bridge between the two engaged cells. MGF-E8 treatment also stimulated integrin-bearing fibroblasts to bind to immobilized aminophospholipids and to engulf apoptotic thymocytes.

R. Hanayama, M. Tanaka, K. Miwa, A. Shinohara, A. Iwamatsu, S. Nagata, Identification of a factor that links apoptotic cells to phagocytes. Nature 417, 182-187 (2002). [Online Journal]