title: Proteomic Analysis of GLUT4 Storage Vesicles Reveals Tumor Suppressor Candidate 5 (TUSC5) as a Novel Regulator of Insulin Action in Adipocytes.
abstract: Insulin signaling augments glucose transport by regulating glucose transporter 4 (GLUT4) trafficking from specialized intracellular compartments, termed GLUT4 storage vesicles (GSVs), to the plasma membrane. Proteomic analysis of GSVs by mass spectrometry revealed enrichment of 59 proteins in these vesicles. We measured reduced abundance of 23 of these proteins following insulin stimulation and assigned these as high confidence GSV proteins. These included established GSV proteins such as GLUT4 and insulin-responsive aminopeptidase, as well as six proteins not previously reported to be localized to GSVs. Tumor suppressor candidate 5 (TUSC5) was shown to be a novel GSV protein that underwent a 3.7-fold increase in abundance at the plasma membrane in response to insulin. siRNA-mediated knockdown of TUSC5 decreased insulin-stimulated glucose uptake, although overexpression of TUSC5 had the opposite effect, implicating TUSC5 as a positive regulator of insulin-stimulated glucose transport in adipocytes. Incubation of adipocytes with TNFα caused insulin resistance and a concomitant reduction in TUSC5. Consistent with previous studies, peroxisome proliferator-activated receptor (PPAR) γ agonism reversed TNFα-induced insulin resistance. TUSC5 expression was necessary but insufficient for PPARγ-mediated reversal of insulin resistance. These findings functionally link TUSC5 to GLUT4 trafficking, insulin action, insulin resistance, and PPARγ action in the adipocyte. Further studies are required to establish the exact role of TUSC5 in adipocytes.
authors.affiliation: From the Charles Perkins Centre, School of Molecular Bioscience, and The Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia, and.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Fazakerley
authors.affiliation: From the Charles Perkins Centre, School of Molecular Bioscience, and The Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia, and.
authors.forename: Sheyda
authors.initials: S
authors.lastname: Naghiloo
authors.affiliation: From the Charles Perkins Centre, School of Molecular Bioscience, and The Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia, and.
authors.forename: Rima
authors.initials: R
authors.lastname: Chaudhuri
authors.affiliation: the Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, United Kingdom.
authors.forename: Françoise
authors.initials: F
authors.lastname: Koumanov
authors.affiliation: From the Charles Perkins Centre, School of Molecular Bioscience, and The Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia, and.
authors.forename: James G
authors.initials: JG
authors.lastname: Burchfield
authors.affiliation: From the Charles Perkins Centre, School of Molecular Bioscience, and.
authors.forename: Kristen C
authors.initials: KC
authors.lastname: Thomas
authors.affiliation: From the Charles Perkins Centre, School of Molecular Bioscience, and The Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia, and.
authors.forename: James R
authors.initials: JR
authors.lastname: Krycer
authors.affiliation: The Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia, and.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Prior
authors.affiliation: From the Charles Perkins Centre, School of Molecular Bioscience, and The Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia, and.
authors.forename: Ben L
authors.initials: BL
authors.lastname: Parker
authors.affiliation: The Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia, and.
authors.forename: Beverley A
authors.initials: BA
authors.lastname: Murrow
authors.affiliation: From the Charles Perkins Centre, School of Molecular Bioscience, and The Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia, and.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Stöckli
authors.affiliation: From the Charles Perkins Centre, School of Molecular Bioscience, and The Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia, and.
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Meoli
authors.affiliation: the Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, United Kingdom.
authors.forename: Geoffrey D
authors.initials: GD
authors.lastname: Holman
authors.affiliation: From the Charles Perkins Centre, School of Molecular Bioscience, and The Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia, and School of Medicine, University of Sydney, Sydney, New South Wales 2006, Australia, david.james@sydney.edu.au.
authors.forename: David E
authors.initials: DE
authors.lastname: James
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000502:physiology*; D000818:Animals; D051275:Glucose Transporter Type 4 / Q000378:metabolism*; D007328:Insulin / Q000502:physiology*; D008297:Male; D051379:Mice; D040901:Proteomics; D051381:Rats; D017208:Rats, Wistar; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000502:physiology*
chemical_list: D051275:Glucose Transporter Type 4; D007328:Insulin; C495694:Slc2a4 protein, rat; C517385:Trarg1 protein, rat; D025521:Tumor Suppressor Proteins
keywords: adipocyte; glucose transporter type 4 (GLUT4); insulin; insulin resistance; membrane trafficking; tumor suppressor candidate 5 (TUSC5)