A novel, evolutionarily conserved protein phosphatase complex involved in cisplatin sensitivity.
Using a combination of tandem affinity purification tagging and mass spectrometry, we characterized a novel, evolutionarily conserved protein phosphatase 4 (PP4)-containing complex (PP4cs, protein phosphatase 4, cisplatin-sensitive complex) that plays a critical role in the eukaryotic DNA damage response. PP4cs is comprised of the catalytic subunit PP4C; a known regulatory subunit, PP4R2; and a novel protein that we termed PP4R3. The Saccharomyces cerevisiae PP4R3 ortholog Psy2 was identified previously in a screen for sensitivity to the DNA-damaging agent and anticancer drug cisplatin. We demonstrated that deletion of any of the PP4cs complex orthologs in S. cerevisiae elicited cisplatin hypersensitivity. Furthermore human PP4R3 complemented the yeast psy2 deletion, and Drosophila melanogaster lacking functional PP4R3 (flfl) exhibited cisplatin hypersensitivity, suggesting a highly conserved role for PP4cs in DNA damage repair. Finally we found that PP4R3 may target PP4cs to the DNA damage repair machinery at least in part via an interaction with Rad53 (CHK2).
Gingras
Anne-Claude
AC
Institute for Systems Biology, Seattle, Washington 98103, USA. agingras@systemsbiology.org
Caballero
Michael
M
Zarske
Marcel
M
Sanchez
Amy
A
Hazbun
Tony R
TR
Fields
Stanley
S
Sonenberg
Nahum
N
Hafen
Ernst
E
Raught
Brian
B
Aebersold
Ruedi
R
D002460:Cell Line; D002945:Cisplatin / Q000494:pharmacology*; D017124:Conserved Sequence; D004249:DNA Damage; D004342:Drug Hypersensitivity; D019143:Evolution, Molecular; D006801:Humans; D008954:Models, Biological; D046912:Multiprotein Complexes / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D010749:Phosphoprotein Phosphatases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000032:analysis / Q000378:metabolism; D016415:Sequence Alignment; D020798:Two-Hybrid System Techniques
D046912:Multiprotein Complexes; D029701:Saccharomyces cerevisiae Proteins; D010749:Phosphoprotein Phosphatases; D002945:Cisplatin