mkk-4 encodes a MAP (mitogen-activated protein) kinase kinase that is a member of the MKK4 family of MAPKK's; MKK-4 activity is required in presynaptic neurons, in a dose-dependent manner, for normal presynaptic development and morphology; in regulating presynaptic organization, MKK-4 acts upstream of PMK-3/MAPK and downstream of DLK-1/MAPKKK, whose levels are negatively regulated by the RPM-1 ubiquitin ligase; a functional MKK-4::GFP fusion protein is expressed in the cytoplasm of many neurons as well as in other cell types, including the pharyngeal muscles.
Enables mitogen-activated protein kinase kinase kinase binding activity. Involved in axon regeneration; p38MAPK cascade; and regulation of developmental growth. Located in cytoplasm. Expressed in head; neurons; and pharynx. Human ortholog(s) of this gene implicated in several diseases, including carcinoma (multiple); invasive ductal carcinoma; and prostate carcinoma in situ. Is an ortholog of human MAP2K4 (mitogen-activated protein kinase kinase 4).