part of MAP kinase kinase activity JNK cascade JUN kinase kinase activity https://github.com/geneontology/go-ontology/issues/28520 JNKK Catalysis of the phosphorylation of tyrosine and threonine residues in a c-Jun NH2-terminal kinase (JNK), a member of a subgroup of mitogen-activated protein kinases (MAPKs), which signal in response to cytokines and exposure to environmental stress. JUN kinase kinase (JNKK) is a dual-specificity protein kinase kinase and requires activation by a serine/threonine kinase JUN kinase kinase kinase. Reactome:R-HSA-168162 molecular_function GO:0008545