KIF3A is a subunit of the heterotrimeric kinesin-2 complex, which belongs to the N-kinesin family of microtubule plus-end-directed motor proteins. Along with KIF3B and the cargo-binding protein KAP3, it forms the heterotrimeric kinesin-2 complex that is involved in regulating intracellular transport and mediating microtubule-based motility. The specific functions of KIF3A include roles in regulating bone formation, nephron number, cell survival, and gene expression control. It is also implicated in sperm formation, prostate cancer suppression, and glioblastoma, among others. KIF3A is associated with diseases such as Usher syndrome type I and neuronal ceroid lipofuscinosis.