How does insulin regulate gene expression?

For a subset of genes, insulin exerts a negative effect on transcription; for others, the effect is positive. Insulin controls gene transcription by modifying the binding of transcription factors on insulin-response elements or by regulating their transcriptional activities.

What metabolic pathway is stimulated by insulin?

The insulin transduction pathway is a biochemical pathway by which insulin increases the uptake of glucose into fat and muscle cells and reduces the synthesis of glucose in the liver and hence is involved in maintaining glucose homeostasis.

How does glucose regulate gene expression?

At the transcriptional level, glucose metabolism can alter gene expression directly by (in)activation of proteins that are already bound to the preinitiation complex on the gene promoter.

What genes does insulin regulate?

The INS gene provides instructions for producing the hormone insulin, which is necessary for the control of glucose levels in the blood. Glucose is a simple sugar and the primary energy source for most cells in the body.

Can insulin increase gene expression?

Glucocorticoids and cAMP stimulate gene transcription, while insulin represses both basal and induced gene expression. However, in contrast to PEPCK, glucose induces G6Pase gene transcription, but this is also antagonised by insulin.

What happens when insulin binds to insulin receptor?

At the cellular level, insulin binds to the insulin receptor (IR) on the plasma membrane (PM) and triggers the activation of signaling cascades to regulate metabolism and cell growth.

How does insulin regulate gluconeogenesis?

Insulin exerts direct control of gluconeogenesis by acting on the liver, but also indirectly affects gluconeogenesis by acting on other tissues. The direct effect of insulin was demonstrated in fasted dogs, where portal plasma insulin suppressed hepatic glucose production.

What is lac operon in biology?

The lactose operon (lac operon) is an operon required for the transport and metabolism of lactose in E. coli and many other enteric bacteria. The gene product of lacZ is β-galactosidase which cleaves lactose, a disaccharide, into glucose and galactose.

How is glucose metabolized?

Glucose metabolism involves multiple processes, including glycolysis, gluconeogenesis, and glycogenolysis, and glycogenesis. Glycolysis in the liver is a process that involves various enzymes that encourage glucose catabolism in cells.

What activates insulin gene expression?

High blood glucose levels stimulate insulin gene expression in the β-cells of the pancreas. Although several transcription factors have been implicated in glucose-induced transcription of the insulin gene, the exact molecular mechanisms leading to up-regulation of insulin gene expression are unknown.

How does insulin regulate FoxO1?

Insulin also inactivates FoxO1, which positively regulates PGC1α expression at the transcriptional level by binding to three insulin response elements (IREs) in its promoter (Daitoku et al., 2003).

How does insulin affect gene expression in metabolic pathways?

This effects gene expression in metabolic pathways. In gluconeogenesis, insulin inhibits gene expression of the rate-limiting step, phosphoenolpyruvate carboxylase, as well as fructose-1,6-bisphosphatase and glucose-6-phosphatase. In glycolysis, gene expression of glucokinase and pyruvate kinase increases.

What is the mechanism of insulin secretion?

Mechanisms of Insulin Secretion. Increased levels of glucose induce the “first phase” of glucose-mediated insulin secretion by release of insulin from secretory granules in the β cell. Glucose entry into the β cell is sensed by glucokinase, which phosphorylates glucose to glucose-6-phosphate (G6P), generating ATP.

What is the role of insulin in homeostasis of glucose metabolism?

The homeostasis of glucose metabolism is carried out by 2 signaling cascades: insulin-mediated glucose uptake (IMGU) and glucose-stimulated insulin secretion (GSIS). The IMGU cascade allows insulin to increase the uptake of glucose from skeletal muscle and adipose tissue and suppresses glucose generation by hepatic cells.

How does the insulin-mediated glucose uptake cascade work?

The homeostasis of glucose metabolism is carried out by 2 signaling cascades: insulin-mediated glucose uptake (IMGU) and glucose-stimulated insulin secretion (GSIS). The IMGU cascade allows insulin to increase the uptake of glucose from skeletal muscle and adipose tissue, as well as suppress glucose generation by hepatic cells.