STK40

STK40, also known as serine/threonine kinase 40, has alternative names including SHIK and SgK495. STK40 is a pseudokinase that has kinase homology domains but lacks catalytic activity. It primarily functions by acting as a scaffold protein to assist E3 ubiquitin ligases in binding with substrate proteins, promoting protein ubiquitination and degradation. STK40 regulates the differentiation of Th1 and Th17 cells, plays a crucial role in mediating inflammation and autoimmune disease progression, and promotes K48-linked polyubiquitination and proteasomal degradation by facilitating the interaction between the FOXO transcription factor and the E3 ligase COP1. STK40 is involved in various physiological processes, including cell differentiation, immune response regulation, and possibly energy metabolism regulation. Its abnormal expression is associated with multiple diseases, including autoimmune disorders and tumors.