Chimeric plant calcium/calmodulin-dependent protein kinase gene with a neural visinin-like calcium-binding domain.
Calcium, a universal second messenger, regulates diverse cellular processes in eukaryotes. Ca2+ and Ca2+/calmodulin-regulated protein phosphorylation play a pivotal role in amplifying and diversifying the action of Ca(2+)-binding domain was cloned and characterized from lily. The cDNA clone contains an open reading frame coding for a protein of 520 amino acids. The predicted structure of CCaMK contains a catalytic domain followed by two regulatory domains, a calmodulin-binding domain and a visinin-like Ca(2+)-binding domain. The amino-terminal region of CCaMK contains all 11 conserved subdomains characteristic of serine/threonine protein kinases. The calmodulin-binding region of CCaMK has high homology (79%) to alpha subunit of mammalian Ca2+/calmodulin-dependent protein kinase. The calmodulin-binding region is fused to a neural visinin-like domain that contains three Ca(2+)-binding EF-hand motifs and a biotin-binding site. The Escherichia coli-expressed protein (approximately 56 kDa) binds calmodulin in a Ca(2+)-dependent manner. Furthermore, 45Ca-binding assays revealed that CCaMK directly binds Ca2+. The CCaMK gene is preferentially expressed in developing anthers. Southern blot analysis revealed that CCaMK is encoded by a single gene. The structural features of the gene suggest that it has multiple regulatory controls and could play a unique role in Ca2+ signaling in plants.
Patil
S
S
Department of Horticulture, Washington State University, Pullman 99164-6414, USA.
Takezawa
D
D
Poovaiah
B W
BW
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000096:biosynthesis* / Q000737:chemistry* / Q000235:genetics; D002417:Cattle; D017124:Conserved Sequence; D005136:Eye Proteins / Q000737:chemistry; D015723:Gene Library; D017343:Genes, Plant; D008322:Mammals; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry*; D010944:Plants / Q000201:enzymology* / Q000235:genetics; D016133:Polymerase Chain Reaction; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000737:chemistry; D017386:Sequence Homology, Amino Acid
D002135:Calcium-Binding Proteins; D005136:Eye Proteins; D009419:Nerve Tissue Proteins; D011993:Recombinant Fusion Proteins; C045140:visinin; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002118:Calcium