If phosphatidylserine is the death knell, a new phosphatidylserine-specific receptor is the bellringer.
Recognition of phosphatidylserine (PtdSer) is essential for engulfment of apoptotic cells by mammalian phagocytes. Engagement of a new phosphatidylserine-specific receptor (PtdSerR) appears to be necessary for uptake of apoptotic cells. Many other mammalian receptors have been described to function in the clearance of apoptotic cells. The emerging picture is that many of these receptors may provide the strong adhesion needed to increase the likelihood of contact between the PtdSerR and its phospholipid ligand, which is required for uptake. Furthermore, stimulation of this receptor on different types of phagocytes by apoptotic cells, PtdSer-containing liposomes or an IgM monoclonal anti-PtdSer antibody initiates release of TGFbeta, known to be involved in the anti-inflammatory effects of apoptotic cells. Although highly homologous genes exist in C. elegans and Drosophila melanogaster, their role in engulfment of apoptotic cells remains to be determined.
Fadok
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Program in Cell Biology, Department of Pediatrics, National Jewish Medical and Research Center, Denver, Colorado, CO 80206, USA. fadokv@njc.org
Xue
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Henson
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D000818:Animals; D000893:Anti-Inflammatory Agents / Q000737:chemistry / Q000378:metabolism; D017209:Apoptosis; D006801:Humans; D007448:Invertebrates / Q000166:cytology / Q000378:metabolism; D056484:Jumonji Domain-Containing Histone Demethylases; D008322:Mammals; D010587:Phagocytosis; D010718:Phosphatidylserines / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D000893:Anti-Inflammatory Agents; D010718:Phosphatidylserines; D011956:Receptors, Cell Surface; C408123:phosphatidylserine receptor; C498707:JMJD6 protein, human; D056484:Jumonji Domain-Containing Histone Demethylases