Rad54B targeting to DNA double-strand break repair sites requires complex formation with S100A11.
S100A11 is involved in a variety of intracellular activities such as growth regulation and differentiation. To gain more insight into the physiological role of endogenously expressed S100A11, we used a proteomic approach to detect and identify interacting proteins in vivo. Hereby, we were able to detect a specific interaction between S100A11 and Rad54B, which could be confirmed under in vivo conditions. Rad54B, a DNA-dependent ATPase, is described to be involved in recombinational repair of DNA damage, including DNA double-strand breaks (DSBs). Treatment with bleomycin, which induces DSBs, revealed an increase in the degree of colocalization between S100A11 and Rad54B. Furthermore, S100A11/Rad54B foci are spatially associated with sites of DNA DSB repair. Furthermore, while the expression of p21(WAF1/CIP1) was increased in parallel with DNA damage, its protein level was drastically down-regulated in damaged cells after S100A11 knockdown. Down-regulation of S100A11 by RNA interference also abolished Rad54B targeting to DSBs. Additionally, S100A11 down-regulated HaCaT cells showed a restricted proliferation capacity and an increase of the apoptotic cell fraction. These observations suggest that S100A11 targets Rad54B to sites of DNA DSB repair sites and identify a novel function for S100A11 in p21-based regulation of cell cycle.
Murzik
Ulrike
U
Core Unit Chip Application (CUCA), Institute of Human Genetics and Anthropology, Medical Faculty, Friedrich-Schiller-University, 07740 Jena, Germany.
Hemmerich
Peter
P
Weidtkamp-Peters
Stefanie
S
Ulbricht
Tobias
T
Bussen
Wendy
W
Hentschel
Julia
J
von Eggeling
Ferdinand
F
Melle
Christian
C
D017209:Apoptosis; D002453:Cell Cycle; D049109:Cell Proliferation; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism*; D053903:DNA Breaks, Double-Stranded; D004249:DNA Damage; D004265:DNA Helicases / Q000378:metabolism*; D004260:DNA Repair; D005786:Gene Expression Regulation; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism; D018613:Microscopy, Confocal; D009687:Nuclear Proteins / Q000378:metabolism*; D040901:Proteomics / Q000379:methods; D011995:Recombination, Genetic; D009418:S100 Proteins / Q000378:metabolism*
C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D009687:Nuclear Proteins; C491221:RAD54B protein, human; D009418:S100 Proteins; C072337:S100A11 protein, human; D004265:DNA Helicases