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Target Concepts:
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Query: UNIPROT:P56851 (
epididymal
)
11,273
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The metabolic effects of insulin are initiated by the binding of insulin to the extracellular domain of the insulin receptor within the plasma membrane of muscle and adipose and liver cells. The subsequent activation of the intracellular tyrosine protein kinase activity of the receptor leads to autophosphorylation of the receptor as well as phosphorylation of a number of intracellular proteins. This gives rise to the activation of Ras and phosphatidylinositol 3-kinase and hence to the activation of a number of serine/threanine protein kinases. Many of these kinases appear to be arranged in cascades, including a cascade that results in the activation of mitogen-activated protein kinase and another that may result in the activation of protein kinase B, leading to the inhibition of glycogen synthase kinase-3 and the activation of the 70 kiloDalton ribosomal S6 protein kinase (p70 S6 kinase). We have explored the role of these early events in the the stimulation of glycogen, fatty acid, and protein synthesis by insulin in rat
epididymal
fat cells. Comparisons have been made between the metabolic effects of insulin and those of epidermal growth factor, since these 2 agents have contrasting effects on p70 S6 kinase and mitogen-activated protein kinase. The effects of wortmannin (which inhibits phosphatidylinositol 3-kinase), and rapamycin (which blocks the activation of p70 S6 kinase) have also been studied. These and other studies indicate that the mitogen-activated protein kinase cascade is probably not important in the acute metabolic effects of insulin, but may have a role in the regulation of gene transcription and hence the more long-term effects of insulin. The short-term metabolic effects of insulin appear to involve at least 3 distinct signaling pathways: (1) those leading to increases in glucose transport and the activation of glycogen synthase, acetyl-CoA carboxylase, eukaryotic initiation factor-2B, and phosphodiesterase, which may involve phosphatidylinositol 3-kinase and protein kinase B; (2) those leading to some of the effects of insulin on protein synthesis (formation of eukaryotic initiation factor-4F complex, S6 phosphorylation, and activation of eukaryotic elongation factor-2), which may involve phosphatidylinositol 3-kinase and p70 S6 kinase; and finally, (3) that leading to the activation of pyruvate dehydrogenase, which is unique in apparently not requiring activation of phosphatidylinositol 3-kinase.
Am J
Cardiol
1997 Aug 04
PMID:Multiple signaling pathways involved in the metabolic effects of insulin. 929 55
Sterile inflammation of visceral fat, provoked by dying adipocytes, links the metabolic syndrome to cardiovascular disease. Danger-associated molecular patterns, such as adenosine triphosphate (ATP), are released by activated or dying cells and orchestrate leukocyte infiltration and inflammation via the purinergic receptor P2Y
2
. The gene expression of ATP receptor P2Y
2
did not change in several tissues in the course of obesity, but was increased within
epididymal
fat. Adipose tissue from P2Y
2
-/-
mice consuming high-fat diet (HFD) contained less crown-like structures with a reduced frequency of adipose tissue macrophages (ATMs). This was likely due to decreased leukocyte migration because of missing VCAM-1 exposition on P2Y
2
deficient hypertrophic adipose tissue endothelial cells. Accordingly, P2Y
2
-/-
mice showed blunted traits of the metabolic syndrome: they gained less weight compared to P2Y
2
+/+
controls, while intake of food and movement behaviour remained unchanged. Liver and adipose tissue were smaller in P2Y
2
-/-
animals. Insulin tolerance testing (ITT) performed in obese P2Y
2
-/-
mice revealed a better insulin sensitivity as well as lower plasma C-peptide and cholesterol levels. We demonstrate that interfering with somatic P2Y
2
signalling prevents excessive immune cell deposition in diet-induced obesity (DIO), both attenuating adipose tissue inflammation and ameliorating the metabolic phenotype. Thus, blocking the P2Y
2
cascade may be a promising strategy to limit metabolic disease and its sequelae.
Basic Res
Cardiol
2018 10 18
PMID:Purinergic receptor Y
2
(P2Y
2
)- dependent VCAM-1 expression promotes immune cell infiltration in metabolic syndrome. 3033 62