Kinesin-associated protein 3 is a protein that in humans is encoded by the KIFAP3 (also known as KAP3) 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.
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 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 Armadillo repeats and interacts with the smg GDS protein through these repeats. This protein, which is highly concentrated around the 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 kinesin superfamily protein in the nucleus, and that it plays a role in the interaction of chromosomes with an ATPase motor protein.
^Jimbo T, Kawasaki Y, Koyama R, Sato R, Takada S, Haraguchi K, Akiyama T (April 2002). "Identification of a link between the tumour suppressor APC and the kinesin superfamily". Nat. Cell Biol.4 (4): 323–7. doi:10.1038/ncb779. PMID11912492.
^Shimizu K, Shirataki H, Honda T, Minami S, Takai Y (March 1998). "Complex formation of SMAP/KAP3, a KIF3A/B ATPase motor-associated protein, with a human chromosome-associated polypeptide". J. Biol. Chem.273 (12): 6591–4. doi:10.1074/jbc.273.12.6591. PMID9506951.
Shimizu K, Shirataki H, Honda T, et al. (1998). "Complex formation of SMAP/KAP3, a KIF3A/B ATPase motor-associated protein, with a human chromosome-associated polypeptide". J. Biol. Chem.273 (12): 6591–4. doi:10.1074/jbc.273.12.6591. PMID9506951.
Gregory SG, Barlow KF, McLay KE, et al. (2006). "The DNA sequence and biological annotation of human chromosome 1". Nature441 (7091): 315–21. doi:10.1038/nature04727. PMID16710414.
Lim J, Hao T, Shaw C, et al. (2006). "A protein-protein interaction network for human inherited ataxias and disorders of Purkinje cell degeneration". Cell125 (4): 801–14. doi:10.1016/j.cell.2006.03.032. PMID16713569.
Stauber T, Simpson JC, Pepperkok R, Vernos I (2007). "A role for kinesin-2 in COPI-dependent recycling between the ER and the Golgi complex". Curr. Biol.16 (22): 2245–51. doi:10.1016/j.cub.2006.09.060. PMID17113389.