Open AccessInvolvement of STAP‐2 in Brk‐mediated phosphorylation and activation of STAT5 in breast cancer cells
Author(s) -
Ikeda Osamu,
Mizushima Akihiro,
Sekine Yuichi,
Yamamoto Chikako,
Muromoto Ryuta,
Nanbo Asuka,
Oritani Kenji,
Yoshimura Akihiko,
Matsuda Tadashi
Publication year - 2011
Publication title -
cancer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.035
H-Index - 141
eISSN - 1349-7006
pISSN - 1347-9032
DOI - 10.1111/j.1349-7006.2010.01842.x
Subject(s) - pleckstrin homology domain , signal transducing adaptor protein , cancer research , gene knockdown , phosphorylation , stat5 , microbiology and biotechnology , sh2 domain , breast cancer , signal transduction , proto oncogene tyrosine protein kinase src , biology , cancer , chemistry , medicine , biochemistry , gene
Signal‐transducing adaptor protein (STAP)‐2 is a recently identified adaptor protein that contains Pleckstrin homology and Src homology 2‐like domains, and is also known to be a substrate of breast tumor kinase (Brk). In a previous study, we found that STAP‐2 upregulated Brk‐mediated activation of signal transducer and activator of transcription (STAT) 3 in breast cancer cells. Here, we examined the involvement of STAP‐2 in Brk‐mediated STAT5 activation in breast cancer cells. Ectopic expression of STAP‐2 induced Brk‐mediated transcriptional activity of STAT5. Furthermore, STAP‐2‐knockdown in T47D breast cancer cells induced a marked decrease in proliferation that was as strong as that after Brk‐ or STAT5b‐knockdown. Regarding the mechanism, the Pleckstrin homology domain of STAP‐2 is likely to participate in the process by which Brk phosphorylates and activates STAT5. Taken together, our findings provide insights toward the development of novel therapeutic strategies as well as novel prognostic values in breast carcinomas. ( Cancer Sci 2011; 102: 756–761)