Heterodimerization of the two motor subunits of the heterotrimeric kinesin, KRP85/95.

The heterotrimeric kinesin-related motor protein, KRP85/95 is assembled from two kinesin-related polypeptides, SpKRP85 and SpKRP95, together with an uncharacterized 115 kDa polypeptide. Here we report the deduced amino acid sequence of SpKRP95, a close relative of SpKRP85. Both SpKRP85 and SpKRP95 are predicted to have a tripartite domain organization consisting of an N-terminal motor domain, a central stalk domain capable of coiled-coil formation, and a second globular C-terminal domain. The sequences of the central stalk domains predict that SpKRP85 and SpKRP95 should be capable of forming heterodimeric coiled coils. Furthermore, SpKRP85-SpKRP95 complexes can be immunoprecipitated from a cell-free translation system, providing direct evidence that SpKRP85 and SpKRP95 are capable of heterodimerization.