Candidate Adaptor Protein CED-6 Promotes the Engulfment of Apoptotic Cells in C. elegans

The rapid engulfment (phagocytosis) of cells undergoing programmed cell death (apoptosis) is a fundamental biological process that is not well understood. Here we report the cloning and functional characterization of ced-6, a gene specifically required for the engulfment of apoptotic cells in the nematode C. elegans. The CED-6 protein contains a phosphotyrosine binding domain at its N terminus and a proline/serine-rich region in its C-terminal half. Genetic mosaic analysis demonstrates that ced-6 acts within engulfing cells. We also show that ced-6 can promote the engulfment of cells at both early and late stages of apoptosis. Our data suggest that CED-6 is an adaptor molecule acting in a signal transduction pathway that specifically mediates the recognition and engulfment of apoptotic cells.