Proliferating cell nuclear antigen is protected from degradation by forming a complex with MutT Homolog2.
Proliferating cell nuclear antigen (PCNA) has been demonstrated to interact with multiple proteins involved in several metabolic pathways such as DNA replication and repair. However, there have been fewer reports about whether these PCNA-binding proteins influence stability of PCNA. Here, we observed a physical interaction between PCNA and MutT homolog2 (MTH2), a new member of the MutT-related proteins that hydrolyzes 8-oxo-7,8-dihydrodeoxyguanosine triphosphate (8-oxo-dGTP). In several unstressed human cancer cell lines and in normal human fibroblast cells, PCNA and MTH2 formed a complex and their mutual binding fragments were confirmed. It was intriguing that PCNA and MTH2 were dissociated dependent on acetylation of PCNA, which in turn induced degradation of PCNA in response to UV irradiation, but not in response to other forms of DNA-damaging stress. To further explore the link between dissociation of PCNA-MTH2 and degradation of PCNA, RNAi against MTH2 was performed to mimic the dissociated status of PCNA to evaluate changes in the half-life of PCNA. Knockdown of MTH2 significantly promoted degradation of PCNA, suggesting that the physiological interaction of PCNA-MTH2 may confer protection from degradation for PCNA, whereas UV irradiation accelerates PCNA degradation by inducing dissociation of PCNA-MTH2. Moreover, secondary to degradation of PCNA, UV-induced inhibition of DNA synthesis or cell cycle progression was enhanced. Collectively, our data demonstrate for the first time that PCNA is protected by this newly identified partner molecule MTH2, which is related to DNA synthesis and cell cycle progression.
Yu
Yu
Y
Key Laboratory of Carcinogenesis and Translational Research (Education Ministry), Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing 100191, China.
Cai
Jian-Ping
JP
Tu
Bo
B
Wu
Lipeng
L
Zhao
Ying
Y
Liu
Xiangyu
X
Li
Lian
L
McNutt
Michael A
MA
Feng
Jingnan
J
He
Qihua
Q
Yang
Yang
Y
Wang
Haiying
H
Sekiguchi
Mutsuo
M
Zhu
Wei-Guo
WG
D000107:Acetylation / Q000187:drug effects / Q000528:radiation effects; D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D015153:Blotting, Western; D002453:Cell Cycle; D002460:Cell Line; D045744:Cell Line, Tumor; D000077209:Decitabine; D003848:Deoxyguanine Nucleotides / Q000378:metabolism; D031541:Fluorescence Resonance Energy Transfer; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D047468:Immunoprecipitation; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D016877:Oxidants / Q000494:pharmacology; D010727:Phosphoric Diester Hydrolases / Q000235:genetics / Q000378:metabolism*; D018809:Proliferating Cell Nuclear Antigen / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects / Q000528:radiation effects; D011755:Pyrophosphatases / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D013936:Thymidine / Q000378:metabolism; D014162:Transfection; D014466:Ultraviolet Rays; D000096964:Nudix Hydrolases
D001374:Azacitidine; D000077209:Decitabine; D003848:Deoxyguanine Nucleotides; D006861:Hydrogen Peroxide; D008164:Luminescent Proteins; D016877:Oxidants; D010727:Phosphoric Diester Hydrolases; D018809:Proliferating Cell Nuclear Antigen; D011755:Pyrophosphatases; D011993:Recombinant Fusion Proteins; D013936:Thymidine; C078206:8-oxodeoxyguanosine triphosphate; C543721:NUDT15 protein, human; D000096964:Nudix Hydrolases