Identification of kinesin-C, a calmodulin-binding carboxy-terminal kinesinin animal (Strongylocentrotus purpuratus) cells

Several novel members of the kinesin superfamily, until now identified only in plants, are unique in their ability to bind calmodulin in the presence of Ca2+. Here, we identify the first such kinesin in an animal system. Sequ ence analysis of this new motor, called kinesin-C, predicts that it is a la rge carboxy-terminal kinesin, 1624 amino acid residues in length, with a pr edicted molecular mass of 181 kDa. Kinesin-C is predicted to contain a kine sin motor domain at its carboxy terminus, linked to a segment of alpha-heli cal coiled-coil 950 amino acid residues long, ending with an amino-terminal proline-rich tail domain. A putative calmodulin-binding domain resides at the extreme carboxy terminus of the motor polypeptide, and recombinant kine sin-C binds to a calmodulin-affinity column in a Ca2+-dependent fashion. Th e presence of this novel calmodulin-binding motor in sea urchin embryos sug gests that it plays a critical role in Ca2+-dependent events during early s ea urchin development. (C) 1999 Academic Press.