Abstract
The c-Jun N-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) signaling pathway mediates stress responses in cells. JNK activity is regulated by a protein kinase cascade consisting of a MAPK kinase (MKK) and a MAPK kinase kinase (MAPKKK). β-Arrestin-2 acts as a scaffold by directly binding to the JNK3 isoform and also by recruiting MKK4 and the MAPKKK apoptosis-signaling kinase-1 (ASK1). In this study, we demonstrate by co-precipitation that the extended N-terminal region of JNK3 mediates binding to the C terminus of β-arrestin-2 and that the N terminus of JNK3 is required for its activation via β-arrestin-2. We have used site-specific mutagenesis to identify key residues within the N terminus of JNK3 that are essential for binding and demonstrate that this region represents an independent β-arrestin-2 binding motif that can be fused to other MAPKs and permit their recruitment to the scaffold complex. In addition, we demonstrate that JNK3 recruits MKK4 to the β-arrestin-2 scaffold complex by binding to the MAPK docking domain (D-domain) located within the N terminus of MKK4. These findings uncover molecular determinants of β-arrestin-2 scaffold complex assembly and assign a previously unrecognized role for the unique extended N terminus of JNK3. © 2008 by The American Society for Biochemistry and Molecular Biology, Inc.
Original language | English |
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Pages (from-to) | 15903-15911 |
Number of pages | 8 |
Journal | Journal of Biological Chemistry |
Volume | 283 |
Issue number | 23 |
DOIs | |
Publication status | Published - 6 Jun 2008 |