Kinesin-II, the heteromeric kinesin

The kinesins constitute a large family of motor proteins: which are respons ible for the distribution of numerous organelles, vesicles and macromolecul ar complexes throughout the cell. One class of these molecular motors, kine sin-TI, is unique in that these proteins are typically found as heterotrime ric complexes containing two different, though related, kinesin-like motor subunits, and a single nonmotor subunit. The heteromeric nature of these,ki nesins appears to have resulted in a class of combinatorial kinesins which can 'mix and match' different motor subunits. Another novel feature of thes e motors is that the activities of several kinesin-IT representatives are e ssential in the assembly of motile and nonmotile cilia, a role not attribut ed to any other kinesin. This review presents a brief overview of the struc ture and biological functions of kinesin-II, the heteromeric kinesin.