Effect of dehydroepiandrosterone (DHEA) on Akt and protein kinase C zeta (PKCζ) phosphorylation in different tissues of C57BL6, insulin receptor substrate (IRS)1 −/− , and IRS2 −/− male mice fed a high-fat diet

2016 ◽  
Vol 159 ◽  
pp. 110-120 ◽  
Author(s):  
Kazutaka Aoki ◽  
Kazuki Tajima ◽  
Masataka Taguri ◽  
Yasuo Terauchi
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Insulin Receptor ◽  
High Fat Diet ◽  
Insulin Receptor Substrate ◽  
Male Mice ◽  
High Fat ◽  
Kinase C ◽  
Protein Kinase C Zeta ◽  
Different Tissues

scholarly journals Shp2 Is Required for Protein Kinase C-dependent Phosphorylation of Serine 307 in Insulin Receptor Substrate-1

2005 ◽  
Vol 280 (38) ◽  
pp. 32693-32699 ◽  
Author(s):  
Karsten Müssig ◽  
Harald Staiger ◽  
Hendrik Fiedler ◽  
Klaus Moeschel ◽  
Alexander Beck ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Insulin Receptor ◽  
Insulin Receptor Substrate ◽  
Insulin Receptor Substrate 1 ◽  
Kinase C

scholarly journals Diets enriched with cereal brans or inulin modulate protein kinase C activity and isozyme expression in rat colonic mucosa

2000 ◽  
Vol 84 (5) ◽  
pp. 635-643 ◽  
Author(s):  
Anne-Maria Pajari ◽  
Seija Oikarinen ◽  
Soile Gråsten ◽  
Marja Mutanen
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Wheat Bran ◽  
High Fat Diet ◽  
Colon Carcinogenesis ◽  
Rat Colon ◽  
High Fat ◽  
Tumour Development ◽  
Kinase C ◽  
Cereal Brans

The role of dietary fibres in colon carcinogenesis is controversial. To elucidate the mechanisms by which different dietary fibre sources may affect colonic tumour development, we studied the effects of diets enriched with cereal brans or inulin on protein kinase C (PKC) activity and isozyme expression in rat colon. Male Wistar rats (twelve per group) were fed one of the following AIN-93G-based diets () for 4 weeks: a non-fibre high-fat diet or one of the four high-fat diets supplemented with either rye, oat or wheat bran or inulin at 100 g/kg diet. The fat concentration (20 g/100 g) and fatty acid composition of the non-fibre high-fat diet was designed to approximate that in a typical Western-type diet. In the proximal colon, rats fed the inulin diet had a significantly higher membrane PKC activity and a higher membrane PKC δ level than rats fed the non-fibre diet (P<0·05). In the distal colon, rats fed the inulin and oat bran diets had a higher total PKC activity and a higher membrane PKC β2 level than rats fed the wheat-bran diet. Rats in the non-fibre and wheat-bran groups had the lowest concentrations of luminal diacylglycerol. In conclusion, feeding of wheat bran resulted in low distal PKC activity and expression of PKC β2, a PKC isozyme related to colonic cell proliferation and increased susceptibility for colon carcinogenesis, which may explain in part the protective effect of wheat bran against tumour development in a number of experimental colon cancer studies. The increase in PKC activity and PKC β2 expression by feeding inulin may be a drawback of inulin as a functional food.

scholarly journals The Role of the Cullin-5 E3 Ubiquitin Ligase in the Regulation of Insulin Receptor Substrate-1

2012 ◽  
Vol 2012 ◽  
pp. 1-8
Author(s):  
Christine Zhiwen Hu ◽  
Jaswinder K. Sethi ◽  
Thilo Hagen
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Insulin Receptor ◽  
Ubiquitin Ligases ◽  
Insulin Receptor Substrate ◽  
E3 Ubiquitin Ligases ◽  
Kinase C ◽  
Cullin 5 ◽  
Socs Proteins ◽  
Protein Kinase C Activation

Background. SOCS proteins are known to negatively regulate insulin signaling by inhibiting insulin receptor substrate-1 (IRS1). IRS1 has been reported to be a substrate for ubiquitin-dependent proteasomal degradation. Given that SOCS proteins can function as substrate receptor subunits of Cullin-5 E3 ubiquitin ligases, we examined whether Cullin-5 dependent ubiquitination is involved in the regulation of basal IRS1 protein stability and signal-induced IRS1 degradation.Findings. Our results indicate that basal IRS1 stability varies between cell types. However, the Cullin-5 E3 ligase does not play a major role in mediating IRS1 ubiquitination under basal conditions. Protein kinase C activation triggered pronounced IRS1 destabilization. However, this effect was also independent of the function of Cullin-5 E3 ubiquitin ligases.Conclusions. In conclusion, SOCS proteins do not exert a negative regulatory effect on IRS1 by functioning as substrate receptors for Cullin-5-based E3 ubiquitin ligases both under basal conditions and when IRS1 degradation is induced by protein kinase C activation.

scholarly journals Phosphorylation of Ser357of Rat Insulin Receptor Substrate-1 Mediates Adverse Effects of Protein Kinase C-δ on Insulin Action in Skeletal Muscle Cells

2008 ◽  
Vol 283 (17) ◽  
pp. 11226-11233 ◽  
Author(s):  
Rizwana Sanaullah Waraich ◽  
Cora Weigert ◽  
Hubert Kalbacher ◽  
Anita M. Hennige ◽  
Stefan Z. Lutz ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Adverse Effects ◽  
Insulin Receptor ◽  
Insulin Action ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Insulin Receptor Substrate ◽  
Kinase C

scholarly journals Protein Kinase C-ζ Phosphorylates Insulin Receptor Substrate-1, -3, and -4 But Not -2: Isoform Specific Determinants of Specificity in Insulin Signaling

Endocrinology ◽  
2008 ◽  
Vol 149 (5) ◽  
pp. 2451-2458 ◽  
Author(s):  
Sihoon Lee ◽  
Edward G. Lynn ◽  
Jeong-a Kim ◽  
Michael J. Quon
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Insulin Receptor ◽  
Negative Feedback ◽  
Insulin Signaling ◽  
Kinase Assay ◽  
Insulin Receptor Substrate ◽  
Kinase C ◽  
Pi3k Activity ◽  
Pkc Ζ

Protein kinase C-ζ, a downstream effector of phosphatidylinositol 3-kinase (PI3K), phosphorylates insulin receptor substrate (IRS)-1 on serine residues impairing activation of PI3K in response to insulin. Because IRS-1 is upstream from PI3K, this represents a negative feedback mechanism that may contribute to signal specificity in insulin action. To determine whether similar feedback pathways exist for other IRS isoforms, we evaluated IRS-2, -3, and -4 as substrates for PKC-ζ. In an in vitro kinase assay, purified recombinant PKC-ζ phosphorylated IRS-1, -3 and -4 but not IRS-2. Similar results were obtained with an immune-complex kinase assay demonstrating that wild-type, but not kinase-deficient mutant PKC-ζ, phosphorylated IRS-1, -3, and -4 but not IRS-2. We evaluated functional consequences of serine phosphorylation of IRS isoforms by PKC-ζ in NIH-3T3IR cells cotransfected with epitope-tagged IRS proteins and either PKC-ζ or empty vector control. Insulin-stimulated IRS tyrosine phosphorylation was impaired by overepxression of PKC-ζ for IRS-1, -3, and -4 but not IRS-2. Significant insulin-stimulated increases in PI3K activity was coimmunoprecipitated with all IRS isoforms. In cells overexpressing PKC-ζ there was marked inhibition of insulin-stimulated PI3K activity associated with IRS-1, -3 and -4 but not IRS-2. That is, PI3K activity associated with IRS-2 in response to insulin was similar in control cells and cells overexpressing PKC-ζ. We conclude that IRS-3 and -4 are novel substrates for PKC-ζ that may participate in a negative feedback pathway for insulin signaling similar to IRS-1. The inability of PKC-ζ to phosphorylate IRS-2 may help determine specific functional roles for IRS-2.

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