Docking interactions in the c-Jun N-terminal kinase pathway.
The c-Jun N-terminal kinase (JNK) signaling pathway is a major mediator of stress responses in cells. Similar to other mitogen-activated protein kinases (MAPKs), JNK activity is controlled by a cascade of protein kinases and by protein phosphatases, including dual-specificity MAPK phosphatases. Components of the JNK pathway associate with scaffold proteins that modulate their activities and cellular localization. The JNK-interacting protein-1 (JIP-1) scaffold protein specifically binds JNK, MAPK kinase 7 (MKK7), and members of the mixed lineage kinase (MLK) family, and regulates JNK activation in neurons. In this study we demonstrate that distinct regions within the N termini of MKK7 and the MLK family member dual leucine zipper kinase (DLK) mediate their binding to JIP-1. We have also identified amino acids in JNK required for: (a) binding to JIP-1 and for JIP-1-mediated JNK activation, (b) docking to MAPK kinase 4 (MKK4) and efficient phosphorylation by MKK4, and (c) docking to its substrate c-Jun and efficient c-Jun phosphorylation. None of the amino acids identified were essential for JNK docking to MKK7 or the dual-specificity phosphatase MAPK phosphatase 7 (MKP7). These findings uncover molecular determinants of JIP-1 scaffold complex assembly and demonstrate that there are overlapping, but also distinct, binding determinants within JNK that mediate interactions with scaffold proteins, activators, phosphatases, and substrates.
Mooney
Lorraine M
LM
School of Biological Sciences, University of Manchester, 2.205 Stopford Building, Oxford Road, Manchester M13 9PT, United Kingdom.
Whitmarsh
Alan J
AJ
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D019556:COS Cells; D019281:Dimerization; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction
D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases