MAP3K2 and Autoimmunity: The MEKK2 kinase mutant (MEKK2KM) can still stabilize LET1 and SUMM2, as well as enhancing cell death triggered by SUMM2, indicating that MEKK2 likely serves as a scaffold protein, rather than a kinase, to stabilize the SUMM2 and LET1 protein complex that activates autoimmunity [76].