title: HUWE1 is a molecular link controlling RAF-1 activity supported by the Shoc2 scaffold.
abstract: Scaffold proteins play a critical role in controlling the activity of the extracellular signal-regulated kinase 1/2 (ERK1/2) pathway. Shoc2 is a leucine-rich repeat scaffold protein that acts as a positive modulator of ERK1/2 signaling. However, the precise mechanism by which Shoc2 modulates the activity of the ERK1/2 pathway is unclear. Here we report the identification of the E3 ubiquitin ligase HUWE1 as a binding partner and regulator of Shoc2 function. HUWE1 mediates ubiquitination and, consequently, the levels of Shoc2. Additionally, we show that both Shoc2 and HUWE1 are necessary to control the levels and ubiquitination of the Shoc2 signaling partner, RAF-1. Depletion of HUWE1 abolishes RAF-1 ubiquitination, with corresponding changes in ERK1/2 pathway activity occurring. Our results indicate that the HUWE1-mediated ubiquitination of Shoc2 is the switch that regulates the transition from an active to an inactive state of the RAF-1 kinase. Taken together, our results demonstrate that HUWE1 is a novel player involved in regulating ERK1/2 signal transmission through the Shoc2 scaffold complex.
authors.affiliation: Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA.
authors.forename: Eun Ryoung
authors.initials: ER
authors.lastname: Jang
authors.affiliation: Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA.
authors.forename: Ping
authors.initials: P
authors.lastname: Shi
authors.affiliation: Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA.
authors.forename: Jamal
authors.initials: J
authors.lastname: Bryant
authors.affiliation: Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA.
authors.forename: Jing
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA.
authors.forename: Vikas
authors.initials: V
authors.lastname: Dukhande
authors.affiliation: Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA.
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Gentry
authors.affiliation: Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA.
authors.forename: HyeIn
authors.initials: H
authors.lastname: Jang
authors.affiliation: Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA.
authors.forename: Myoungkun
authors.initials: M
authors.lastname: Jeoung
authors.affiliation: Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA emilia.galperin@uky.edu.
authors.forename: Emilia
authors.initials: E
authors.lastname: Galperin
mesh_terms: D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D005786:Gene Expression Regulation; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008958:Models, Molecular; D054730:Protein Interaction Domains and Motifs; D019908:Proto-Oncogene Proteins c-raf / Q000378:metabolism*; D015398:Signal Transduction; D025521:Tumor Suppressor Proteins; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism*; D054875:Ubiquitination
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; C112913:SHOC2 protein, human; D025521:Tumor Suppressor Proteins; C502830:HUWE1 protein, human; D044767:Ubiquitin-Protein Ligases; D019908:Proto-Oncogene Proteins c-raf