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Plant calcium‐dependent protein kinase‐related kinases (CRKs) do not require calcium for their activities
Author(s) -
Furumoto Tsuyoshi,
Ogawa Noriyuki,
Hata Shingo,
Izui Katsura
Publication year - 1996
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(96)01090-3
Subject(s) - kinase , adapter molecule crk , complementary dna , casein kinase 1 , biology , protein kinase a , sh3 domain , biochemistry , calmodulin , phosphorylation , microbiology and biotechnology , gene , enzyme , proto oncogene tyrosine protein kinase src , signal transducing adaptor protein
In plants, calcium‐dependent protein kinases (CDPKs) make up a large family that is characterized by a C‐terminal calmodulin(CaM)‐like domain. Recently, a novel carrot cDNA clone encoding an atypical CDPK, which has a significantly degenerate sequence in the CaM‐like domain, was found and named CDPK‐related protein kinase (CRK) [Lindzen, E. and Choi, J.H. (1995) Plant Mol. Biol. 28, 785–797]. We obtained two different cDNA clones from maize which encode CRKs. For the first enzymatic characterization of CRK, a maize cDNA clone was expressed in E. coli . The recombinant protein efficiently phosphorylated casein, a conventional protein substrate. Notably, in this in vitro phosphorylation assay, the kinase activity did not require calcium as an activator. Thus, CRKs were suggested to be novel calcium‐independent protein kinases having a degenerate CaM domain, the function of which remains to be elucidated.