Nuclear translocation of dihydrofolate reductase is not a pre-requisite for DNA damage induced apoptosis.
Dihydrofolate reductase (DHFR) is a key enzyme for the synthesis of thymidylate, and therefore, of DNA. By applying subcellular proteomic analysis, we identified that the DHFR protein was translocated from cytoplasm into the nucleus when apoptosis was induced by NSC606985, a camptothecin analogue. The nuclear translocation of DHFR protein during apoptosis was independent of the cellular context, but it was more sensitive in cell death induction by DNA damaging agents such as doxorubicin, etoposide and ultraviolent radiation than endoplasmic reticulum stressors (brefeldin-A and tunicamycin) and anti-microtubule agents (paclitaxel and nocodozole). The addition of methotrexate almost completely blocked the nuclear translocation of DHFR protein. Further investigations showed that the nuclear translocation of DHFR was not a pre-requisite for DNA damage induced apoptosis. Therefore, its potential biological significance remains to be further explored.
Institute of Health Science, Shanghai Institutes for Biological Sciences of Chinese Academy of Sciences and Shanghai Jiao-Tong University School of Medicine, No. 225, Chongqing South Road, 200025, Shanghai, China.
Ting-Ting
TT
Yuan
Ying
Y
Huang
Ci-Xiang
CX
Zhou
Yun
Y
Yu
Li-Shun
LS
Wang
Han-Yi
HY
Zhuang
Guo-Qiang
GQ
Chen
D000595:Amino Acid Sequence; D017209:Apoptosis / Q000187:drug effects; D002166:Camptothecin / Q000031:analogs & derivatives / Q000494:pharmacology; D053148:Caspase 3 / Q000378:metabolism; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000187:drug effects / Q000201:enzymology*; D004249:DNA Damage; D004305:Dose-Response Relationship, Drug; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D004789:Enzyme Activation / Q000187:drug effects; D005047:Etoposide / Q000494:pharmacology; D006801:Humans; D007938:Leukemia / Q000201:enzymology / Q000473:pathology; D008727:Methotrexate / Q000494:pharmacology; D008870:Microtubules / Q000187:drug effects; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000032:analysis / Q000737:chemistry; D021381:Protein Transport / Q000187:drug effects; D013762:Tetrahydrofolate Dehydrogenase / Q000378:metabolism*
C514334:NSC606985; D009363:Neoplasm Proteins; D005047:Etoposide; D013762:Tetrahydrofolate Dehydrogenase; D053148:Caspase 3; D002166:Camptothecin; D008727:Methotrexate