title: Structure and Functional Characterization of the Conserved JAK Interaction Region in the Intrinsically Disordered N-Terminus of SOCS5.
abstract: SOCS5 can negatively regulate both JAK/STAT and EGF-receptor pathways and has therefore been implicated in regulating both the immune response and tumorigenesis. Understanding the molecular basis for SOCS5 activity may reveal novel ways to target key components of these signaling pathways. The N-terminal region of SOCS5 coordinates critical protein interactions involved in inhibition of JAK/STAT signaling, and a conserved region within the N-terminus of SOCS5 mediates direct binding to the JAK kinase domain. Here we have characterized the solution conformation of this conserved JAK interaction region (JIR) within the largely disordered N-terminus of SOCS5. Using nuclear magnetic resonance (NMR) chemical shift analysis, relaxation measurements, and NOE analysis, we demonstrate the presence of preformed structural elements in the JIR of mouse SOCS5 (mSOCS5175-244), consisting of an α-helix encompassing residues 224-233, preceded by a turn and an extended structure. We have identified a phosphorylation site (Ser211) within the JIR of mSOCS5 and have investigated the role of phosphorylation in modulating JAK binding using site-directed mutagenesis.
authors.affiliation: †Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia.
authors.forename: Indu R
authors.initials: IR
authors.lastname: Chandrashekaran
authors.affiliation: †Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia.
authors.forename: Biswaranjan
authors.initials: B
authors.lastname: Mohanty
authors.affiliation: §The Department of Medical Biology, University of Melbourne, Parkville, Victoria 3052, Australia.
authors.forename: Edmond M
authors.initials: EM
authors.lastname: Linossi
authors.affiliation: §The Department of Medical Biology, University of Melbourne, Parkville, Victoria 3052, Australia.
authors.forename: Laura F
authors.initials: LF
authors.lastname: Dagley
authors.affiliation: †Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia.
authors.forename: Eleanor W W
authors.initials: EW
authors.lastname: Leung
authors.affiliation: §The Department of Medical Biology, University of Melbourne, Parkville, Victoria 3052, Australia.
authors.forename: James M
authors.initials: JM
authors.lastname: Murphy
authors.affiliation: §The Department of Medical Biology, University of Melbourne, Parkville, Victoria 3052, Australia.
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Babon
authors.affiliation: §The Department of Medical Biology, University of Melbourne, Parkville, Victoria 3052, Australia.
authors.forename: Sandra E
authors.initials: SE
authors.lastname: Nicholson
authors.affiliation: †Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia.
authors.forename: Raymond S
authors.initials: RS
authors.lastname: Norton
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D051379:Mice; D016297:Mutagenesis, Site-Directed; D020125:Mutation, Missense; D010766:Phosphorylation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D050826:Suppressor of Cytokine Signaling Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: C485811:Socs5 protein, mouse; D050826:Suppressor of Cytokine Signaling Proteins