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Involvement of protein tyrosine phosphatase SHP‐1 in the inhibition of membrane‐bound guanylate cyclase GC‐A activity stimulated by atrial natriuretic factor
Author(s) -
Chang ChungHo,
Chang GeenDong,
Yang SuRong,
Chen ChenYu,
Chung WanYu
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a797
Subject(s) - immunoprecipitation , phosphorylation , chemistry , transfection , phosphatase , tyrosine , protein tyrosine phosphatase , proto oncogene tyrosine protein kinase src , biochemistry , small heterodimer partner , enzyme , microbiology and biotechnology , biology , transcription factor , gene , nuclear receptor
We examined whether SHP‐1 can regulate the activation of membrane‐bound guanylate cyclase GC‐A by atrial natriuretic factor (ANF). Co‐immunoprecipitation experiments indicated that SHP‐1 associated with GC‐A in an ANF‐dependent manner. Transfection of SHP‐1 into CHO and MCF‐7 cells inhibited ANF‐stimulated GC‐A activity. GC‐A contains two SHP‐1 substrate consensus sequences (amino acids 816‐821 and 1014‐1020) in its catalytic domain (GC‐c). Transfection studies showed that SHP‐1 inhibited the activity of GC‐c, indicating that SHP‐1 interacts with the catalytic domain. Interestingly, substitution of Phe at Tyr 818 or Tyr 1017 on GC‐c led to the loss of enzyme activity. Examination of the tyrosine phosphorylation state of GC‐A reveals that GC‐A is not dephosphorylated by SHP‐1. Transfection of v‐Src enhanced ANF‐stimulated GC‐A activity in MCF‐7 cells, whereas inhibition of Src activity decreased it. Co‐immunoprecipitation experiments indicate that transfection of SHP‐1 disrupts the association of Src with GC‐A. These results indicate that SHP‐1 is a GC‐A associated protein, and that SHP‐1 inhibits the activity of GC‐A at least partly by disrupting the association of Src with GC‐A. This work was supported by grants from the National Institute of Health and the National Science Council.