Send to

Choose Destination
J Biol Chem. 1997 Oct 3;272(40):24751-4.

Identification of c-Jun NH2-terminal protein kinase (JNK)-activating kinase 2 as an activator of JNK but not p38.

Author information

Department of Pathology, Division of Molecular and Cellular Pathology, the University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.


c-Jun NH2-terminal protein kinase (JNK), a distant member of the mitogen-activated protein (MAP) kinase family, regulates gene expression in response to various extracellular stimuli. JNK is activated by JNK-activating kinase 1 (JNKK1), a dual specificity protein kinase that phosphorylates JNK on threonine 183 and tyrosine 185 residues. Here we show that JNKK2, a novel member of the MAP kinase kinase family, was phosphorylated and activated by MEKK1, a MAP kinase kinase kinase in the JNK signaling cascade. JNKK2 activity was also stimulated by constitutively active forms of Rac and Cdc42Hs, members of the Rho small GTP-binding protein family. Unlike JNKK1 that activates both JNK and p38 MAP kinases, JNKK2 stimulated only JNK. Transient transfection assays demonstrated that JNKK2 potentiated the stimulation of c-Jun transcriptional activity by MEKK1. The existence of multiple JNK-activating kinases may contribute to the specificity of the JNK signaling cascade.

[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for HighWire
Loading ...
Support Center