A Drosophila homolog of LIM-kinase phosphorylates cofilin and induces actin cytoskeletal reorganization.
Mammalian LIM-kinases (LIMKs) phosphorylate cofilin and induce actin cytoskeletal reorganization. To elucidate the functional roles of LIMKs in vivo during developmental processes, we attempted to isolate the cDNA encoding a Drosophila homolog of LIMK (DLIMK) and identified two isoforms of DLIMK transcripts coding for proteins with 1235 and 1257 amino acids, possessing the structure composed of two LIM domains, a PDZ domain, a protein kinase domain, and an unusual long C-terminal extension. In situ hybridization analysis in Drosophila embryos detected the uniformly distributed DLIMK mRNA in stages 2 to 5. In vitro kinase reaction revealed that DLIMK efficiently phosphorylates Drosophila cofilin (twinstar) specifically at Ser-3, the site responsible for inactivation of its actin-depolymerizing activity. When expressed in cultured cells, wild-type DLIMK, but not its kinase-inactive form, induced changes in actin cytoskeletal organization. These observations suggest that the LIMK-cofilin signaling pathway for regulating actin filament dynamics is evolutionarily conserved between Drosophila and mammals.
Ohashi
K
K
Biological Institute, Sendai, 980-8578, Japan.
Hosoya
T
T
Takahashi
K
K
Hing
H
H
Mizuno
K
K
D051339:Actin Depolymerizing Factors; D000199:Actins / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D003001:Cloning, Molecular; D003599:Cytoskeleton / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000196:embryology / Q000201:enzymology*; D004625:Embryo, Nonmammalian / Q000201:enzymology; D020224:Expressed Sequence Tags; D018507:Gene Expression Regulation, Developmental; D006367:HeLa Cells; D006801:Humans; D017403:In Situ Hybridization; D054461:Lim Kinases; D008840:Microfilament Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011494:Protein Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017385:Sequence Homology; D014162:Transfection
D051339:Actin Depolymerizing Factors; D000199:Actins; D008840:Microfilament Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D011494:Protein Kinases; C515892:LIMK1 protein, human; D054461:Lim Kinases