A novel kinesin-like protein with a calmodulin-binding domain

• Published in: Plant molecular biology Vol. 31; no. 1; pp. 87 - 100
• Main Authors: Wang, W. (Washington State Univ., Pullman, WA (USA). Dept. of Horticulture), Takezawa, D, Narasimhulu, S.B, Reddy, A.S.N, Poovaiah, B.W
• Format: Journal Article
• Language: English
• Published: Netherlands 01-04-1996
• Subjects: Adenosine Triphosphatases - metabolism; ADN; Amino Acid Sequence; Animals; ANTERA; ANTHERE; ANTHERS; Base Sequence; Calcium - metabolism; CALCIUM BINDING PROTEINS; CALMODULIN; Calmodulin - metabolism; Calmodulin-Binding Proteins - chemistry; Calmodulin-Binding Proteins - genetics; Calmodulin-Binding Proteins - metabolism; CALMODULINA; CALMODULINE; CODE GENETIQUE; CODIGO GENETICO; DNA; DNA, Complementary; Escherichia coli; Escherichia coli - genetics; EXPRESION GENICA; EXPRESSION DES GENES; GENE EXPRESSION; GENETIC CODE; Kinesins - genetics; Kinesins - metabolism; Molecular Sequence Data; NICOTIANA; Nicotiana - genetics; Nicotiana tabacum; Plant Proteins - chemistry; Plant Proteins - genetics; Plant Proteins - metabolism; Plants, Toxic; Protein Binding; Protein Structure, Secondary; PROTEINAS QUE LIGAN CALCIO; PROTEINE DE LIAISON CALCIUM; Sequence Homology, Amino Acid; NASA Program Space Biology; NASA Discipline Number 40-50; NASA Discipline Plant Biology; Non-NASA Center
• ISSN: 0167-4412; 1573-5028
• DOI: 10.1007/BF00020609

Calcium regulates diverse developmental processes in plants through the action of calmodulin. A cDNA expression library from developing anthers of tobacco was screened with 35S-labeled calmodulin to isolate cDNAs encoding calmodulin-binding proteins. Among several clones isolated, a kinesin-like gene (TCK1) that encodes a calmodulin-binding kinesin-like protein was obtained. The TCK1 cDNA encodes a protein with 1265 amino acid residues. Its structural features are very similar to those of known kinesin heavy chains and kinesin-like proteins from plants and animals, with one distinct exception. Unlike other known kinesin-like proteins, TCK1 contains a calmodulin-binding domain which distinguishes it from all other known kinesin genes. Escherichia coli-expressed TCK1 binds calmodulin in a Ca(2+)-dependent manner. In addition to the presence of a calmodulin-binding domain at the carboxyl terminal, it also has a leucine zipper motif in the stalk region. The amino acid sequence at the carboxyl terminal of TCK1 has striking homology with the mechanochemical motor domain of kinesins. The motor domain has ATPase activity that is stimulated by microtubules. Southern blot analysis revealed that TCK1 is coded by a single gene. Expression studies indicated that TCK1 is expressed in all of the tissues tested. Its expression is highest in the stigma and anther, especially during the early stages of anther development. Our results suggest that Ca2+/calmodulin may play an important role in the function of this microtubule-associated motor protein and may be involved in the regulation of microtubule-based intracellular transport.