title: Identification of sucrose non-fermenting-related kinase (SNRK) as a suppressor of adipocyte inflammation.
abstract: In this study, the role of sucrose non-fermenting-related kinase (SNRK) in white adipocyte biology was investigated. SNRK is abundantly expressed in adipose tissue, and the expression level is decreased in obese mice. SNRK expression is repressed by inflammatory signals but increased by insulin sensitizer in cultured adipocytes. In vivo, adipose tissue SNRK expression can be decreased by lipid injection but enhanced by macrophage ablation. Knocking down SNRK in cultured adipocytes activates both JNK and IKKβ pathways as well as promotes lipolysis. Insulin-stimulated Akt phosphorylation and glucose uptake are impaired in SNRK knockdown adipocytes. Phosphoproteomic analysis with SNRK knockdown adipocytes revealed significantly decreased phosphorylation of 49 proteins by 25% or more, which are involved in various aspects of adipocyte function with a clear indication of attenuated mTORC1 signaling. Phosphorylation of 43 proteins is significantly increased by onefold or higher, among which several proteins are known to be involved in inflammatory pathways. The inflammatory responses in SNRK knockdown adipocytes can be partially attributable to defective mTORC1 signaling, since rapamycin treatment activates IKKβ and induces lipolysis in adipocytes. In summary, SNRK may act as a suppressor of adipocyte inflammation and its presence is necessary for maintaining normal adipocyte function.
authors.affiliation: Hallett Center for Diabetes and Endocrinology, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA.
authors.forename: Yujie
authors.initials: Y
authors.lastname: Li
authors.forename: Yaohui
authors.initials: Y
authors.lastname: Nie
authors.forename: Ynes
authors.initials: Y
authors.lastname: Helou
authors.forename: Guoxian
authors.initials: G
authors.lastname: Ding
authors.forename: Bin
authors.initials: B
authors.lastname: Feng
authors.forename: Gang
authors.initials: G
authors.lastname: Xu
authors.forename: Arthur
authors.initials: A
authors.lastname: Salomon
authors.forename: Haiyan
authors.initials: H
authors.lastname: Xu
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D052436:Adipose Tissue, White / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D051550:I-kappa B Kinase / Q000378:metabolism; D007249:Inflammation / Q000235:genetics / Q000378:metabolism*; D007328:Insulin / Q000494:pharmacology; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D008066:Lipolysis / Q000187:drug effects / Q000502:physiology*; D008297:Male; D000076222:Mechanistic Target of Rapamycin Complex 1; D051379:Mice; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D058570:TOR Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism
chemical_list: D007328:Insulin; D046912:Multiprotein Complexes; C490993:Snrk protein, mouse; D000076222:Mechanistic Target of Rapamycin Complex 1; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases; D051550:I-kappa B Kinase; C496562:Ikbkb protein, mouse; D048031:JNK Mitogen-Activated Protein Kinases