Novel Ser/Thr protein phosphatase 5 (PP5) regulated targets during DNA damage identified by proteomics analysis.
The DNA damage response likely includes a global phosphorylation signaling cascade process for sensing the damaged DNA condition and coordinating responses to cope with and repair the perturbed cellular state. We utilized a label-free liquid chromatography-mass spectrometry approach to evaluate changes in protein phosphorylation associated with PP5 activity during the DNA damage response. Biological replicate analyses of bleomycin-treated HeLa cells expressing either WT-PP5 or mutant inactive PP5 lead to the identification of six potential target proteins of PP5 action. Four of these putative targets have been previously reported to be involved in DNA damage responses. Using phospho-site specific antibodies, we confirmed that phosphorylation of one target, ribosomal protein S6, was selectively decreased in cells overexpressing catalytically inactive PP5. Our findings also suggest that PP5 may play a role in controlling translation and in regulating substrates for proline-directed kinases, such as MAP kinases and cyclin-dependent protein kinases that are involved in response to DNA damage.
Ham
Bryan M
BM
Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
Jayachandran
Hemalatha
H
Yang
Feng
F
Jaitly
Navdeep
N
Polpitiya
Ashoka D
AD
Monroe
Matthew E
ME
Wang
Ling
L
Zhao
Rui
R
Purvine
Samuel O
SO
Livesay
Eric A
EA
Camp
David G
DG
Rossie
Sandra
S
Smith
Richard D
RD
D000595:Amino Acid Sequence; D002384:Catalysis; D004249:DNA Damage; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism*; D010749:Phosphoprotein Phosphatases / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation; D040901:Proteomics; D053719:Tandem Mass Spectrometry
D009687:Nuclear Proteins; D010749:Phosphoprotein Phosphatases; C089641:protein phosphatase 5