title: HsRec2/Rad51L1, a protein influencing cell cycle progression, has protein kinase activity.
abstract: Human Rec2/Rad51L1 is a member of the Rad51 family of proteins. Although recombinase activity, typical of this family, could not be established, its overexpression in mammalian cells has been shown to cause a delay in G1. Moreover, since hsRec2/Rad51L1 has been found to be induced by both ionizing and UV irradiation, it is likely that hsRec2/Rad51L1 is elevated following any DNA damage and causes a G1 delay to allow time for DNA repair to occur. Limited homology with catalytic domains X and XI of protein kinase A suggested that kemptide, an artificial substrate containing one phosphorylatable residue, a serine, might serve as a substrate for hsRec2/Rad51L1. Here, we report that hsRec2/Rad51L1 can phosphorylate kemptide, as well as myelin basic protein, p53, cyclin E, and cdk2, but not a peptide substrate containing tyrosine only. The finding that hsRec2/Rad51L1 exhibits protein kinase activity is a first step toward identifying a mechanism whereby this protein affects the cell cycle.
authors.affiliation: Department of Biological Sciences, University of Delaware, Newark, Delaware, 19716, USA.
authors.forename: P A
authors.initials: PA
authors.lastname: Havre
authors.forename: M
authors.initials: M
authors.lastname: Rice
authors.forename: R
authors.initials: R
authors.lastname: Ramos
authors.forename: E B
authors.initials: EB
authors.lastname: Kmiec
mesh_terms: D042846:CDC2-CDC28 Kinases; D002453:Cell Cycle; D019927:Cyclin E / Q000378:metabolism; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D015870:Gene Expression; D006801:Humans; D010766:Phosphorylation; D011494:Protein Kinases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011506:Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D051135:Rad51 Recombinase; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
chemical_list: D019927:Cyclin E; D004268:DNA-Binding Proteins; D011506:Proteins; C413002:RAD51B protein, human; D011993:Recombinant Fusion Proteins; D016159:Tumor Suppressor Protein p53; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases; C495153:RAD51 protein, human; D051135:Rad51 Recombinase