title: Proteomic analysis of livers from fat-fed mice deficient in either PKCδ or PKCε identifies Htatip2 as a regulator of lipid metabolism.
abstract: Insulin resistance contributes to the development of Type 2 diabetes, and is associated with lipid oversupply. Deletion of isoforms of the lipid-activated protein kinase C (PKC) family, PKCδ or PKCε, improves insulin action in fat-fed mice, but differentially affects hepatic lipid metabolism. To investigate the mechanisms involved, we employed an in vivo adaptation of SILAC to examine the effects of a fat diet together with deletion of PKCδ or PKCε on the expression of liver proteins. We identified a total of 3359 and 3488 proteins from the PKCδ and PKCε knockout study groups, respectively, and showed that several enzymes of lipid metabolism were affected by the fat diet. In fat-fed mice, 23 proteins showed changes upon PKCδ deletion while 19 proteins were affected by PKCε deletion. Enzymes of retinol metabolism were affected by the absence of either PKC. Pathway analysis indicated that monosaccharide metabolism was affected only upon PKCδ deletion, while isoprenoid biosynthesis was affected in a PKCε-specific manner. Certain proteins were regulated inversely, including HIV-1 tat interactive protein 2 (Htatip2). Overexpression or knockdown of Htatip2 in hepatocytes affected fatty acid storage and oxidation, consistent with a novel role in mediating the differential effects of PKC isoforms on lipid metabolism. All MS data have been deposited in the ProteomeXchange with identifier PXD000971 (http://proteomecentral.proteomexchange.org/dataset/PXD000971).
authors.affiliation: Diabetes and Metabolism Division, Garvan Institute of Medical Research, Sydney, New South Wales, Australia.
authors.forename: Bing M
authors.initials: BM
authors.lastname: Liao
authors.forename: Katy
authors.initials: K
authors.lastname: Raddatz
authors.forename: Ling
authors.initials: L
authors.lastname: Zhong
authors.forename: Benjamin L
authors.initials: BL
authors.lastname: Parker
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Raftery
authors.forename: Carsten
authors.initials: C
authors.lastname: Schmitz-Peiffer
mesh_terms: D000818:Animals; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics / Q000378:metabolism; D059305:Diet, High-Fat; D017353:Gene Deletion; D055786:Gene Knockout Techniques; D007333:Insulin Resistance; D050356:Lipid Metabolism; D008099:Liver / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D051745:Protein Kinase C-delta / Q000235:genetics*; D051744:Protein Kinase C-epsilon / Q000235:genetics*; D040901:Proteomics; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D012097:Repressor Proteins; C525546:Tip30 protein, mouse; D025521:Tumor Suppressor Proteins; D051745:Protein Kinase C-delta; D051744:Protein Kinase C-epsilon
keywords: Animal proteomics; Glucose intolerance; High-fat diet; Insulin resistance; Liver; Protein kinase C; SILAC