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Induction of p53 dependent apoptosis upon overexpression of a nuclear protein tyrosine phosphatase
Author(s) -
Radha Vegesna,
Sudhakar Ch,
Swarup Ghanshyam
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)00734-6
Subject(s) - protein tyrosine phosphatase , p53 protein , apoptosis , phosphatase , chemistry , tyrosine , protein phosphatase 2 , nuclear protein , microbiology and biotechnology , biochemistry , phosphorylation , biology , gene , transcription factor
Two ubiquitously expressed protein tyrosine phosphatases, PTP‐S2 and PTP‐S4 (also known as TC 45 and TC 48 , respectively), are alternately spliced products of the same gene. Overexpression of PTP‐S2 by transient transfection induced chromatin condensation and nuclear fragmentation, typical of apoptosis. Expression of PTP‐S4 resulted in a much lower number of cells with apoptotic phenotype. PTP‐S2 induced apoptosis in MCF7 and A549 human tumor cell lines which are p53 positive but not in HeLa and SW620 cells which are p53 negative. Apoptosis induced by PTP‐S2 in MCF7 cells was inhibited by cotransfection with mutant p53 (Arg‐273→His) but not by wild type p53. PTP‐S2 induced apoptosis was inhibited by antiapoptotic protein Bcl2 and certain inhibitors of caspases. These results suggest that the nuclear tyrosine phosphatase PTP‐S2 induces p53 dependent, serum starvation independent and caspase mediated apoptosis.