title: Gadd45a interacts with aurora-A and inhibits its kinase activity.
abstract: Centrosome stability is required for successful mitosis in mammalian cells. Amplification of the centrosome leads to chromosomal missegregation and generation of aneuploidy, which are closely associated with cell transformation and tumorigenesis (Doxsey, S. J. (2001) Nat. Cell Biol. 3, E105-E108; Hinchcliffe, E. H., and Sluder, G. (2001) Genes Dev. 15, 1167-1181; Pihan, G. A., Purohit, A., Wallace, J., Malhotra, R., Liotta, L., and Doxsey, S. J. (2001) Cancer Res. 61, 2212-2219). However, there are currently limited insights into mechanism(s) for this critical biological event. Here we show that Gadd45a, a DNA damage-inducible protein that is regulated by tumor suppressors p53 and BRCA1, participates in the maintenance of centrosome stability. Mouse embryonic fibroblasts derived from gadd45a knock-out mice exhibit centrosome amplification (designated as increased centrosome numbers). Introduction of exogenous Gadd45a into mouse embryonic fibroblasts isolated from gadd45a-null mice substantially restored the normal centrosome profile. In contrast to p21(waf1/cip1), which ensures coordinated initiation of centrosome, Gadd45a had no significant effect on centrosome duplication in S phase. Interestingly Gadd45a was found to physically associate with Aurora-A protein kinase, whose deregulated expression results in centrosome abnormality. Furthermore Gadd45a was demonstrated to strongly inhibit Aurora-A kinase activity and to antagonize Aurora-A-induced centrosome amplification. These findings identify a novel mechanism for Gadd45a in the maintenance of centrosome stability and broaden understandings of p53- and BRCA1-regulated signaling pathways in maintaining genomic fidelity.
authors.affiliation: State Key Laboratory of Molecular Oncology, Cancer Institute, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China.
authors.forename: Shujuan
authors.initials: S
authors.lastname: Shao
authors.forename: Yang
authors.initials: Y
authors.lastname: Wang
authors.forename: Shunqian
authors.initials: S
authors.lastname: Jin
authors.forename: Yongmei
authors.initials: Y
authors.lastname: Song
authors.forename: Xiaoxia
authors.initials: X
authors.lastname: Wang
authors.forename: Wenhong
authors.initials: W
authors.lastname: Fan
authors.forename: Zhiying
authors.initials: Z
authors.lastname: Zhao
authors.forename: Ming
authors.initials: M
authors.lastname: Fu
authors.forename: Tong
authors.initials: T
authors.lastname: Tong
authors.forename: Lijia
authors.initials: L
authors.lastname: Dong
authors.forename: Feiyue
authors.initials: F
authors.lastname: Fan
authors.forename: Ningzhi
authors.initials: N
authors.lastname: Xu
authors.forename: Qimin
authors.initials: Q
authors.lastname: Zhan
mesh_terms: D000818:Animals; D064096:Aurora Kinase A; D064127:Aurora Kinases; D018797:Cell Cycle Proteins / Q000378:metabolism / Q000502:physiology*; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D009687:Nuclear Proteins / Q000378:metabolism / Q000502:physiology*; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D000097642:GADD45 Proteins
chemical_list: D064096:Aurora Kinase A; D064127:Aurora Kinases; D018797:Cell Cycle Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D004791:Enzyme Inhibitors; D009687:Nuclear Proteins; D017346:Protein Serine-Threonine Kinases; C493957:Cdkn1a protein, mouse; C439070:GADD45A protein, human; D000097642:GADD45 Proteins; C499072:Gadd45a protein, mouse; C576918:Aurka protein, mouse