Kinesin Family, Member 21B (KIF21B)

KIF21B belongs to a family of plus end-directed kinesin motor proteins. Neurons use kinesin and dynein microtubule-dependent motor proteins to transport essential cellular components along axonal and dendritic microtubules. The deduced 1,668-amino acid protein contains 3 characteristic kinesin domains: an N-terminal head motor domain, a coiled-coil stalk region, and a C-terminal tail. The stalk region has a conserved cluster of negatively charged amino acids, and the tail has 7 consensus WD40 repeats. Western blot analysis detected mouse Kif21b at an apparent molecular mass of about 178 kD in brain and spleen, with lower expression in testis. Immunofluorescence staining localized Kif21b in all regions of the mouse nervous system examined, although the level of Kif21b in sciatic nerve was quite low.