期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2003
卷号：100
期号：5
页码：2284-2289
DOI：10.1073/pnas.0530298100
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The p53 tumor suppressor protein plays a crucial role in tumorigenesis by controlling cell-cycle progression and apoptosis. We have previously described a transcript designated tumor suppressor activated pathway-6 (TSAP6) that is up-regulated in the p53-inducible cell line, LTR6. Cloning of the murine and human full-length TSAP6 cDNA revealed that it encodes a 488-aa protein with five to six transmembrane domains. This gene is the murine and human homologue of the recently published rat pHyde. Antibodies raised against murine and human TSAP6 recognize a 50- to 55-kDa band induced by p53. Analysis of the TSAP6 promoter identified a functional p53-responsive element. Functional studies demonstrated that TSAP6 antisense cDNA diminished levels of the 50- to 55-kDa protein and decreased significantly the levels of p53-induced apoptosis. Furthermore, TSAP6 small interfering RNA inhibited apoptosis in TSAP6-overexpressing cells. Yeast two-hybrid analysis followed by GST/in vitro-transcribed/translated pull-down assays and in vivo coimmunoprecipitations revealed that TSAP6 associated with Nix, a proapoptotic Bcl-2-related protein and the Myt1 kinase, a negative regulator of the G2/M transition. Moreover, TSAP6 enhanced the susceptibility of cells to apoptosis and cooperated with Nix to exacerbate this effect. Cell-cycle studies indicated that TSAP6 could augment Myt1 activity. Overall, these data suggest that TSAP6 may act downstream to p53 to interface apoptosis and cell-cycle progression.
