title: The beta-arrestin-2 scaffold protein promotes c-Jun N-terminal kinase-3 activation by binding to its nonconserved N terminus.
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). beta-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 beta-arrestin-2 and that the N terminus of JNK3 is required for its activation via beta-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 beta-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 beta-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 beta-arrestin-2 scaffold complex assembly and assign a previously unrecognized role for the unique extended N terminus of JNK3.
authors.affiliation: Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom.
authors.forename: Chun
authors.initials: C
authors.lastname: Guo
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Whitmarsh
mesh_terms: D020816:Amino Acid Motifs / Q000502:physiology; D000818:Animals; D019390:Arrestins / Q000235:genetics / Q000378:metabolism*; D019556:COS Cells; D002522:Chlorocebus aethiops; D004789:Enzyme Activation / Q000502:physiology; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D048848:MAP Kinase Kinase Kinase 5 / Q000235:genetics / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000502:physiology*; D048057:Mitogen-Activated Protein Kinase 10 / Q000235:genetics / Q000378:metabolism*; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000502:physiology; D000071560:beta-Arrestin 2; D000071557:beta-Arrestins
chemical_list: C000605254:ARRB2 protein, human; D019390:Arrestins; D007527:Isoenzymes; D000071560:beta-Arrestin 2; D000071557:beta-Arrestins; D048057:Mitogen-Activated Protein Kinase 10; D048848:MAP Kinase Kinase Kinase 5; C482858:MAP3K5 protein, human; D020929:Mitogen-Activated Protein Kinase Kinases