The JIP group of mitogen-activated protein kinase scaffold proteins

Activation of the c-Jun NH2-terminal kinase (JNK) group of mitogen-activate d protein (MAP) kinases is mediated by a protein kinase cascade. This signa ling mechanism may be coordinated by the interaction of components of the p rotein kinase cascade with scaffold proteins. The JNK-interacting protein ( JIP) group of scaffold proteins selectively mediates signaling by the mixed -lineage kinase (MLK)-->MAP kinase kinase 7 (MKK7)-->JNK pathway. The scaff old proteins JIP1 and JIP2 interact to form oligomeric complexes that accum ulate in peripheral cytoplasmic projections extended at the cell surface. T he JIP proteins function by aggregating components of a MAP kinase module ( including MLK, MKK7, and JNK) and facilitate signal transmission by the pro tein kinase cascade.