Characterization of a calmodulin-regulated Ca2+-dependent-protein-kinase-related protein kinase, AtCRK1, from Arabidopsis.
An AtCRK1 [Arabidopsis thaliana CDPK (Ca2+-dependent protein kinase)-related protein kinase 1] has been characterized molecularly and biochemically. AtCRK1 contains the kinase catalytic domain and a CaM (calmodulin)-binding site. Our results demonstrated that AtCRK1 could bind CaM in a Ca2+-dependent manner. This kinase phosphorylated itself and substrates such as histone IIIS and syntide-2 in a Ca2+-independent manner and the activity was stimulated by several CaM isoforms through its CaM-binding domain. This domain was localized within a stretch of 39 amino acid residues at positions from 403 to 441 with K(d)=67 nM for CaM binding. However, the stimulation amplification of the kinase activity of AtCRK1 by different CaM isoforms was similar.
Wang
Ying
Y
Key Lab of Ministry of Education for Plant Developmental Biology, College of Life Sciences, Wuhan University, Wuhan 430072, People's Republic of China.
Liang
Shuping
S
Xie
Qi-Guang
QG
Lu
Ying-Tang
YT
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology*; D029681:Arabidopsis Proteins; D001483:Base Sequence; D001665:Binding Sites; D002118:Calcium / Q000502:physiology; D002147:Calmodulin / Q000378:metabolism / Q000502:physiology; D002148:Calmodulin-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011494:Protein Kinases / Q000737:chemistry / Q000378:metabolism*; D011994:Recombinant Proteins / Q000302:isolation & purification
D029681:Arabidopsis Proteins; D002147:Calmodulin; D002148:Calmodulin-Binding Proteins; D011994:Recombinant Proteins; D011494:Protein Kinases; C496961:CRK1 protein, Arabidopsis; D002118:Calcium