期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2015
卷号：112
期号：11
页码：3409-3414
DOI：10.1073/pnas.1419528112
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：SignificanceIn the mitogen-activated protein kinase (MAPK) pathways, N-terminal intrinsically disordered regulatory domains of the MAPK kinases (MKK) control signaling specificity by binding to their cognate MAPKs via docking sites carrying homologous recognition sequences. MKK7 activates the c-Jun N-terminal kinase (JNK) pathway and is the only MKK containing three motifs within its regulatory domain. Here we obtain a comprehensive picture of the structure, dynamics, affinity, stoichiometry, and kinetics of the MKK7-JNK signaling complex. Importantly, we show using a combination of X-ray crystallography and NMR exchange spectroscopy that the second docking site of MKK7 binds to JNK via two alternative binding modes, providing insight into the regulation of signaling specificity by short linear motifs. Signaling specificity in the mitogen-activated protein kinase (MAPK) pathways is controlled by disordered domains of the MAPK kinases (MKKs) that specifically bind to their cognate MAPKs via linear docking motifs. MKK7 activates the c-Jun N-terminal kinase (JNK) pathway and is the only MKK containing three motifs within its regulatory domain. Here, we characterize the conformational behavior and interaction mechanism of the MKK7 regulatory domain. Using NMR spectroscopy, we develop an atomic resolution ensemble description of MKK7, revealing highly diverse intrinsic conformational propensities of the three docking sites, suggesting that prerecognition sampling of the bound-state conformation is not prerequisite for binding. Although the different sites exhibit similar affinities for JNK1, interaction kinetics differ considerably. Importantly, we determine the crystal structure of JNK1 in complex with the second docking site of MKK7, revealing two different binding modes of the docking motif correlating with observations from NMR exchange spectroscopy. Our results provide unique insight into how signaling specificity is regulated by linear motifs and, in general, into the role of conformational disorder in MAPK signaling.
关键词：NMR ; mitogen-activated protein kinase ; intrinsically disordered protein ; signaling ; c-Jun N-terminal kinase
