Serine/Threonine Kinase 40 (STK40)

The deduced 435-amino acid protein has a central serine/threonine protein kinase domain and shares significant homology with SINK. Northern blot analysis detected strong SHIK expression in all tissues examined. Western blot analysis detected a 55-kD endogenous SHIK protein in human embryonic kidney cells. Immunofluorescent staining localized endogenous SHIK to the cytoplasm and nucleus of human embryonic kidney cells.

Huang et al. (2003) determined that SHIK inhibited TNF-dependent activation of NFKB. SHIK also inhibited p53 (TP53) in a dose-dependent manner in a reporter gene assay. Mutation of asp197 to ile abolished the ability of SHIK to inhibit p53-mediated transcription and resulted in a SHIK protein that potentiated p53-mediated transcription.