SPRY domain-containing SOCS box protein 1 （SPSB1） belongs to the SOCS box protein subfamily. SPSB1 includes a central SPRY domain and a C-terminal SOCS box. Even though， some of the SOCS protein subfamilies function as adaptors for a large family of ubiquitin-protein isopeptide ligases to regulate certain signaling pathways， the function of the SSB subfamily remains to be determined. SPSB1 may have an imperative role in enhancing the HGF-induced Erk-Elk-1-SRE pathway. SPSB1 overexpression exhibited no effect on the basal level or epidermal growth factor-induced SRE-luciferase activity.
