Class I MHC heavy chain (HLA-A, HLA-B, HLA-C) is a structural component of what receptor involved in glucose regulation?
It is a structural subunit of the insulin receptor (INSR).
Although hepatocytes do not require insulin to admit glucose, what does insulin help them to regulate?
It helps them regulate their responses to increased glucose.
Which oxide does insulin binding require in order to potentiate its actions?
Insulin binding requires presence of nitric oxide (NO) to potentiate its actions. Low levels of NO are associated with oxidative stress.
What are the insulin receptor substrates (IRS)?
They are the substrates of the Insulin Receptor (INSR) after insulin binds to it.
After insulin has bound to insulin receptor (INSR), what are some of the effects that the insulin receptor substrates 1-3 (IRS 1-3) go on to have?
Increased transport of K+ into cells. Increased GLUT (especially 4) expression on cell surfaces. Increased glycogen (glycogenesis) and fatty acid (lipogenesis) synthesis. Inhibition of lipolysis and glycogenolysis. Increases amino acid transport into cells. Increases transcription and translation of insulin gene (pancreatic). Stimulates growth, DNA synthesis & cell replication.
How are activated Insulin Receptor Subtrate (IRS) proteins enabled to bind and activate other signal transduction molecules?
They contains a region called a phosphotyrosine-binding (PTB) domain, with multiple tyrosines that are phosphorylated by insulin receptor tyrosine kinase (RTK).
Describe relationship between IRS-1 & MAP-K.
A major IRS-1 activity is stimulation of mitogen activated protein kinases (MAP-K). MAP kinases are also called extracellular-signal regulated kinases (ERKs). The most common targets of MAP-Ks are transcriptional regulator proteins that become active and produce protein via translation
What type of diabetes can defects in IRS-1 cause?
Type 2 diabetes mellitus (NIDDM). Peripheral insulin resistance and impaired insulin secretion.