title: The Caenorhabditis elegans p21-activated kinase (CePAK) colocalizes with CeRac1 and CDC42Ce at hypodermal cell boundaries during embryo elongation.
abstract: The p21-activated kinase (PAK) is a downstream target of Rac and CDC42, members of the Ras-related Rho subfamily, that mediates signaling pathway leading to cytoskeletal reorganization. To investigate its function in Caenorhabditis elegans development, we have isolated the cDNA coding for the p21-activated kinase homologue (CePAK) from a C. elegans embryonic cDNA library. This 2.35-kilobase pair cDNA encodes a polypeptide of 572 amino acid residues, with the highly conserved N-terminal p21-binding and the C-terminal kinase domains. Similar to its mammalian and Drosophila counterparts, the CePAK protein expressed in E. coli exhibits binding activity toward GTP-bound CeRac1 and CDC42Ce. Polyclonal antibodies raised against the recombinant CePAK recognize a specific 70-kDa protein from embryonic extracts that displays CeRac1/CDC42Ce-binding and kinase activities. Immunofluorescence analysis indicates that CePAK is specifically expressed at the hypodermal cell boundaries during embryonic body elongation, which involves dramatic cytoskeletal reorganization. Interestingly, CeRac1 and CDC42Ce are found at the same location, which might point to their common involvement in hypodermal cell fusion, a crucial morphogenetic event for nematode development.
authors.affiliation: Glaxo-IMCB Group, Institute of Molecular & Cell Biology, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Republic of Singapore.
authors.forename: W
authors.initials: W
authors.lastname: Chen
authors.forename: S
authors.initials: S
authors.lastname: Chen
authors.forename: S F
authors.initials: SF
authors.lastname: Yap
authors.forename: L
authors.initials: L
authors.lastname: Lim
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000196:embryology / Q000201:enzymology*; D029742:Caenorhabditis elegans Proteins; D018797:Cell Cycle Proteins / Q000378:metabolism*; D018076:DNA, Complementary / Q000737:chemistry; D004330:Drosophila; D005455:Fluorescent Antibody Technique; D019204:GTP-Binding Proteins / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D015723:Gene Library; D015801:Helminth Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D011494:Protein Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D016415:Sequence Alignment; D054462:p21-Activated Kinases; D020744:rac GTP-Binding Proteins
chemical_list: D029742:Caenorhabditis elegans Proteins; D018797:Cell Cycle Proteins; D018076:DNA, Complementary; D015801:Helminth Proteins; D012333:RNA, Messenger; C081779:cdc-42 protein, C elegans; D011494:Protein Kinases; C101878:pak-1 protein, C elegans; D054462:p21-Activated Kinases; D019204:GTP-Binding Proteins; D020744:rac GTP-Binding Proteins