C-ELEGANS PHAGOCYTOSIS AND CELL-MIGRATION PROTEIN CED-5 IS SIMILAR TOHUMAN DOCK180

During programmed cell death, cell corpses are rapidly engulfed(1). Th is engulfment process involves the recognition and subsequent phagocyt osis of cell corpses by engulfing cells(1-4). How cell corpses are eng ulfed is largely unknown, Here we report that ced-5, a gene that is re quired for cell-corpse engulfment in the nematode Caenorhabditis elega n(5), encodes a protein that is similar to the human protein DOCK180 a nd the Drosophila melanogaster protein Myoblast City (MBC), both of wh ich have been implicated in the extension of cell surfaces(6). ced-5 m utants are defective not only in the engulfment of cell corpses but al so in the migrations of two specific gonadal cells, the distal tip cel ls. The expression of human DOCK180 in C. elegans rescued the cell-mig ration defect of a ced-5 mutant. We present evidence that ced-5 functi ons in engulfing cells during the engulfment of cell corpses. We sugge st that ced-5 acts in the extension of the surface of an engulfing cel l around a dying cell during programmed cell death, We name this new f amily of proteins that function in the extension of cell surfaces the CDM (for CED-5, DOCK180 and MBC) family.