SplA/Ryanodine Receptor Domain And SOCS Box Containing Protein 1 (SPSB1)

The deduced 273-amino acid protein shares 50% and 75% amino acid identity with SPSB2 and SPSB4, respectively. SPSB1 contains an N-terminal YxxP motif, a central SPRY domain, and a C-terminal SOCS box.SPRY domain of SPSB1 interacted with MET and that HGF stimulation increased SPSB1-MET interaction. Overexpression of SPSB1 increased HGF-induced reporter gene expression and ERK phosphorylation in HEK293 cells. However, siRNA knockdown of SPSB1 repressed HGF-induced reporter gene expression and also suppressed Elk1 activation. Mutation analysis showed that SPSB1 was phosphorylated at tyr31 upon HGF stimulation, and tyr31-phosphorylated SPSB1 interacted with p120-RASGAP (RASA1) specifically in response to HGF