Enables MAP kinase kinase activity and protein kinase binding activity. Acts upstream of or within several processes, including MAPK cascade; cardiac muscle contraction; and positive regulation of MAPK cascade. Predicted to be located in cytosol. Is expressed in several structures, including alimentary system; brain; early conceptus; genitourinary system; and sensory organ. Human ortholog(s) of this gene implicated in cervical cancer and restrictive cardiomyopathy. Orthologous to human MAP2K3 (mitogen-activated protein kinase kinase 3). [provided by Alliance of Genome Resources, Apr 2022]