Cloning and biochemical characterization of LIMK-2, a protein kinase containing two LIM domains.
We have isolated human and rat clones of the LIM motif-containing protein kinase, termed LIMK-2. LIMK-2 is related to the neuronally expressed LIM-kinase, whose hemizygous deletion appears to result in cognitive impairment in patients with Williams syndrome. The hallmark of this protein family is the presence of 1 or 2-terminal LIM motifs and an atypical C-terminal protein kinase domain. LIMK-2 mRNA was detected by Northern blot analysis in human tissues, most abundantly in placenta, lung, liver, and pancreas, and also in a variety of cell lines including neuronal, glioblastoma, and mammary carcinoma lines. The LIMK-2 transcript was also induced upon neuroectodermal differentiation of mouse P19 embryonal carcinoma cells. A 65 kDa recombinant LIMK-2 protein was identified in 293 cells stably transfected with a LIMK-2 expression vector. An in vitro kinase assay demonstrates LIMK-2 is autophosphorylated and exhibits serine/threonine kinase activity towards the exogenous substrate MBP. The endogenous 65 kDa LIMK-2 protein was detected in a variety of cell lines, and coprecipitates with a 140 kDa tyrosine phosphorylated protein, but was not itself tyrosine phosphorylated. At the subcellular level, LIMK-2 is localized in both the nucleus and in a Triton X-100 soluble fraction.
Smolich
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SUGEN, Inc, Redwood City, CA 94063, USA. beverly@sugen.sf.ca.us
Vo
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Buckley
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Plowman
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Papkoff
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J
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002460:Cell Line; D002467:Cell Nucleus / Q000737:chemistry; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry; D004268:DNA-Binding Proteins; D006801:Humans; D054461:Lim Kinases; D051379:Mice; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000737:chemistry / Q000378:metabolism; D011494:Protein Kinases / Q000737:chemistry / Q000235:genetics*; D017346:Protein Serine-Threonine Kinases; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D012995:Solubility
D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D010750:Phosphoproteins; D012333:RNA, Messenger; D011494:Protein Kinases; C102895:LIMK2 protein, human; D054461:Lim Kinases; C095325:Limk2 protein, mouse; C490644:Limk2 protein, rat; D017346:Protein Serine-Threonine Kinases