ASK1 (Apoptosis Signal-regulating Kinase 1) activates two different subgroups of MAPKK, MKK4 and MKK6, which in turn activate c-Jun N-terminal Kinase (JNK) and p38 MAP Kinase. ASK1 is activated by TNFR and Fas throμgh the interaction with members of the TRAF Family and the Fas-associated protein Daxx. Overexpression of ASK1 induces apoptosis. However, a catalytically inactive form of ASK1 has been shown to inhibit TNF-α induced apoptosis.