Kinesin-associated protein 3 explained

Kinesin-associated protein 3 (KAP3) is a protein that in humans is encoded by the KIFAP3 gene.[1] [2] 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.[3] [4]

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 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. It has also been proposed to act as a clamp, stabilizing the C-terminal half [5] of the otherwise unstable stalk coiled-coil.

Interactions

KIFAP3 has been shown to interact with APC,[6] SMC3[7] and RAP1GDS1.

Further reading

Notes and References

  1. Shimizu K, Kawabe H, Minami S, Honda T, Takaishi K, Shirataki H, Takai Y . SMAP, an Smg GDS-associating protein having arm repeats and phosphorylated by Src tyrosine kinase . J Biol Chem . 271 . 43 . 27013–7 . Dec 1996 . 8900189 . 10.1074/jbc.271.43.27013 . free .
  2. Web site: Entrez Gene: KIFAP3 kinesin-associated protein 3.
  3. Wedaman KP, Meyer DW, Rashid DJ, Cole DG, Scholey JM . Sequence and submolecular localization of the 115-kD accessory subunit of the heterotrimeric kinesin-II (KRP85/95) complex . J. Cell Biol. . 132 . 3 . 371–80 . February 1996 . 8636215 . 2120715 . 10.1083/jcb.132.3.371.
  4. Yamazaki H, Nakata T, Okada Y, Hirokawa N . Cloning and characterization of KAP3: a novel kinesin superfamily-associated protein of KIF3A/3B . Proc. Natl. Acad. Sci. U.S.A. . 93 . 16 . 8443–8 . August 1996 . 8710890 . 38690 . 10.1073/pnas.93.16.8443. 1996PNAS...93.8443Y . free .
  5. Ahmed Z, Mazumdar S, Ray K . Kinesin associated protein, DmKAP, binding harnesses the C-terminal ends of the Drosophila kinesin-2 stalk heterodimer . Biochem Biophys Res Commun . 522 . 2 . 506–511 . February 2020 . 31784087 . 8407544 . 10.1016/j.bbrc.2019.11.111.
  6. Jimbo T, Kawasaki Y, Koyama R, Sato R, Takada S, Haraguchi K, Akiyama T . Identification of a link between the tumour suppressor APC and the kinesin superfamily . Nat. Cell Biol. . 4 . 4 . 323–7 . April 2002 . 11912492 . 10.1038/ncb779 . 10745049 .
  7. Shimizu K, Shirataki H, Honda T, Minami S, Takai Y . 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 . March 1998 . 9506951 . 10.1074/jbc.273.12.6591. free .

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