Sci. STKE, 14 May 2002
Phagocytosis Eating the Dead
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]
Citation: Eating the Dead. Sci. STKE 2002, tw172 (2002).
Science Signaling. ISSN 1937-9145 (online), 1945-0877 (print). Pre-2008: Science's STKE. ISSN 1525-8882