title: c-Abl tyrosine kinase regulates the human Rad9 checkpoint protein in response to DNA damage.
abstract: The ubiquitously expressed c-Abl tyrosine kinase is activated in the apoptotic response of cells to DNA damage. The mechanisms by which c-Abl signals the induction of apoptosis are not understood. Here we show that c-Abl binds constitutively to the mammalian homolog of the Schizosaccharomyces pombe Rad9 cell cycle checkpoint protein. The SH3 domain of c-Abl interacts directly with the C-terminal region of Rad9. c-Abl phosphorylates the Rad9 Bcl-2 homology 3 domain (Tyr-28) in vitro and in cells exposed to DNA-damaging agents. The results also demonstrate that c-Abl-mediated phosphorylation of Rad9 induces binding of Rad9 to the antiapototic Bcl-x(L) protein. The regulation of Rad9 by c-Abl in the DNA damage response is further supported by the demonstration that the interaction between c-Abl and Rad9 contributes to DNA damage-induced apoptosis. These findings indicate that Rad9 is regulated by a c-Abl-dependent mechanism in the apoptotic response to genotoxic stress.
authors.affiliation: Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: Kiyotsugu
authors.initials: K
authors.lastname: Yoshida
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Komatsu
authors.forename: Hong-Gang
authors.initials: HG
authors.lastname: Wang
authors.forename: Donald
authors.initials: D
authors.lastname: Kufe
mesh_terms: D017209:Apoptosis / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D004249:DNA Damage; D005434:Flow Cytometry; D006801:Humans; D010766:Phosphorylation; D011485:Protein Binding; D016315:Proto-Oncogene Proteins c-abl / Q000235:genetics / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D014443:Tyrosine / Q000378:metabolism; D051020:bcl-X Protein
chemical_list: C494811:BCL2L1 protein, human; D018797:Cell Cycle Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D011993:Recombinant Fusion Proteins; D051020:bcl-X Protein; C069930:rad9 protein; D014443:Tyrosine; D016315:Proto-Oncogene Proteins c-abl