title: A novel role of the chromokinesin Kif4A in DNA damage response.
abstract: Chromokinesins are microtubule-motor molecules that possess chromatin binding activity and are important for mitotic and meiotic regulation. The chromokinesin-member Kif4A is unique in that it localizes to nucleus during interphase of the cell cycle. Kif4 deletion by gene targeting in mouse embryonic cells was known to associate with DNA damage response. However, its precise role in DNA damage or repair pathway is not clear. Here we report that Kif4A associates with BRCA2 in a biochemical identification and that the interaction is mediated by the Kif4A C-terminal cargo-binding domain and BRCA2 C-terminal conserved region. Upon nucleus-specific laser micro-irradiation, Kif4A was rapidly recruited to sites of DNA damage. Significantly, the depletion of Kif4A from cells by shRNA impaired the ionizing-radiation induced foci (IRIF) formation of Rad51, both quantitatively and qualitatively. In contrast, the IRIF of gamma-H2AX or NBS1 was largely intact. Moreover, Kif4A knockdown rendered cells hypersensitive to ionizing radiation in a colonogenic survival assay. We further demonstrated that Kif4A deficiency led to significantly decreased homologous recombination in an I-SceI endonuclease induced in vivo recombination assay. Together, our results suggest a novel role for a chromokinesin family member in the DNA damage response by modulating the BRCA2/Rad51 pathway.
authors.affiliation: Department of Biological Chemistry, School of Medicine, University of California, Irvine, California 92697, USA.
authors.forename: Guikai
authors.initials: G
authors.lastname: Wu
authors.forename: Longen
authors.initials: L
authors.lastname: Zhou
authors.forename: Lily
authors.initials: L
authors.lastname: Khidr
authors.forename: Xuning Emily
authors.initials: XE
authors.lastname: Guo
authors.forename: Wankee
authors.initials: W
authors.lastname: Kim
authors.forename: Young Mi
authors.initials: YM
authors.lastname: Lee
authors.forename: Tatiana
authors.initials: T
authors.lastname: Krasieva
authors.forename: Phang-Lang
authors.initials: PL
authors.lastname: Chen
mesh_terms: D024682:BRCA2 Protein / Q000378:metabolism*; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000378:metabolism*; D004249:DNA Damage; D004260:DNA Repair; D005822:Genetic Vectors; D006367:HeLa Cells; D006657:Histones / Q000378:metabolism*; D006801:Humans; D016547:Kinesins / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D051135:Rad51 Recombinase / Q000378:metabolism*; D011995:Recombination, Genetic
chemical_list: D024682:BRCA2 Protein; D018797:Cell Cycle Proteins; C468783:H2AX protein, human; D006657:Histones; C112156:NBN protein, human; D009687:Nuclear Proteins; C495153:RAD51 protein, human; D051135:Rad51 Recombinase; C484228:KIF4A protein, human; D016547:Kinesins