title: The mammalian Ced-1 ortholog MEGF10/KIAA1780 displays a novel adhesion pattern.
abstract: Ced-1 protein is a Caenorhabditis elegans cell surface receptor involved in phagocytosis of dead cells. The gene encoding the mammalian ortholog of Ced-1 is yet to be identified. Here, we describe a potential candidate: human MEGF10. MEGF10 has the overall domain organization of Ced-1, containing a signal peptide, a EMI domain, 17 atypical EGF-like repeats, a transmembrane domain, and a cytoplasmic domain with NPXY and YXXL motifs. MEGF10-EGFP fusion protein expressed in HEK293 cells produced an irregular, mosaic-like pattern on the surface of coated glass. Protruded MEGF10 bound tightly to the glass, in effect "pinning" the cytoplasmic membrane firmly onto the glass, thereby restricting cell motility. These cells also took on a flat appearance. Although MEGF10-EGFP localized throughout the cytoplasmic membrane, no MEGF10-EGFP was found in lamellipodia. The MEGF10-EGFP signal was surrounded by a 1-2-microm-wide dark strip lacking EGFP. Expression analyses of various MEGF10 deletion mutants revealed that the irregular, mosaic-like adhesion pattern characteristic of MEGF10 family members is due to concerted interactions between the EMI and 17 atypical EGF-like domains. Co-culturing of MEGF10-EGFP-expressing cells with apoptotic cells revealed that MEGF10 protein accumulated around the contact region during engulfment of apoptotic cells.
authors.affiliation: Department of Human Genome Research, Kazusa DNA Research Institute, 2-6-7, Kazusa-Kamatari, Kisarazu, Chiba, Japan.
authors.forename: Emiko
authors.initials: E
authors.lastname: Suzuki
authors.forename: Manabu
authors.initials: M
authors.lastname: Nakayama
mesh_terms: D000818:Animals; D017209:Apoptosis; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism; D002455:Cell Division; D002460:Cell Line; D002462:Cell Membrane / Q000737:chemistry; D018920:Coculture Techniques; D003593:Cytoplasm / Q000737:chemistry; D005898:Glass / Q000737:chemistry; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D006801:Humans; D008565:Membrane Proteins / Q000032:analysis* / Q000235:genetics / Q000378:metabolism*; D010587:Phagocytosis; D011107:Polylysine / Q000737:chemistry; D017434:Protein Structure, Tertiary / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000032:analysis / Q000235:genetics
chemical_list: D029742:Caenorhabditis elegans Proteins; C522055:MEGF10, human; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; C422043:ced-1 protein, C elegans; D049452:Green Fluorescent Proteins; D011107:Polylysine