KIFAP3

Kinesin-associated protein 3 is a is_associated_with::protein that in humans is encoded by the KIFAP3 (also known as KAP3) is_associated_with::gene. It is a non-motor, accessory subunit which co-oligomerizes with the motor subunits KIF3A and KIF3B or KIF3C, to form heterotrimeric kinesin-2 motor proteins. Kinesin-2 KAP subunits were initially characterized in echinoderms and mice.

Function
The small G protein GDP dissociation stimulator (smg GDS) is a regulator protein having two activities on a group of small G proteins including the Rho and is_associated_with::Rap1 family members and Ki-Ras; one is to stimulate their GDP/GTP exchange reactions, and the other is to inhibit their interactions with membranes. The protein encoded by this gene contains 9 is_associated_with::Armadillo repeats and interacts with the smg GDS protein through these repeats. This protein, which is highly concentrated around the is_associated_with::endoplasmic reticulum, is phosphorylated by v-src, and this phosphorylation reduces the affinity of the protein for smg GDS. It is thought that this protein serves as a linker between human chromosome-associated polypeptide (HCAP) and KIF3A/B, a is_associated_with::kinesin superfamily protein in the nucleus, and that it plays a role in the interaction of chromosomes with an ATPase motor protein.

Interactions
KIFAP3 has been shown to interact with APC, SMC3 and PPI::RAP1GDS1.