CED-1 is a transmembrane receptor that mediates cell corpse engulfment in C. elegans.
We cloned the C. elegans gene ced-1, which is required for the engulfment of cells undergoing programmed cell death. ced-1 encodes a transmembrane protein similar to human SREC (Scavenger Receptor from Endothelial Cells). We showed that ced-1 is expressed in and functions in engulfing cells. The CED-1 protein localizes to cell membranes and clusters around neighboring cell corpses. CED-1 failed to cluster around cell corpses in mutants defective in the engulfment gene ced-7. Motifs in the intracellular domain of CED-1 known to interact with PTB and SH2 domains were necessary for engulfment but not for clustering. Our results indicate that CED-1 is a cell surface phagocytic receptor that recognizes cell corpses. We suggest that the ABC transporter CED-7 promotes cell corpse recognition by CED-1, possibly by exposing a phospholipid ligand on the surfaces of cell corpses.
Zhou
Z
Z
Howard Hughes Medical Institute, Department of Biology, Building 68, Room 425, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
Hartwieg
E
E
Horvitz
H R
HR
D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D000483:Alleles; D000818:Animals; D030801:Animals, Genetically Modified; D017209:Apoptosis / Q000502:physiology*; D017173:Caenorhabditis elegans; D029742:Caenorhabditis elegans Proteins; D003001:Cloning, Molecular; D016384:Consensus Sequence; D004815:Epidermal Growth Factor / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation / Q000502:physiology; D010587:Phagocytosis / Q000502:physiology*; D010641:Phenotype; D011485:Protein Binding / Q000502:physiology; D011971:Receptors, Immunologic / Q000235:genetics; D018110:Receptors, Lipoprotein; D051116:Receptors, Scavenger; D012091:Repetitive Sequences, Nucleic Acid; D051122:Scavenger Receptors, Class B; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000502:physiology; D019076:Transgenes / Q000502:physiology; D018909:src Homology Domains / Q000502:physiology
D018528:ATP-Binding Cassette Transporters; C112887:CED-7 protein, C elegans; D029742:Caenorhabditis elegans Proteins; D008565:Membrane Proteins; D011971:Receptors, Immunologic; D018110:Receptors, Lipoprotein; D051116:Receptors, Scavenger; C454739:Scarb1 protein, mouse; D051122:Scavenger Receptors, Class B; C422043:ced-1 protein, C elegans; D004815:Epidermal Growth Factor