How does insulin binding activate the insulin receptor List

How does insulin binding activate the insulin receptor? List the steps of the insulin signal-transduction pathway. How is insulin signaling terminated?

Solution

Insulin signaling- Focus on “ leads to the mobilization of glucose transporters to the cell surface’’

-The hormone released in response to increased blood- glucose levels .

- a peptide hormone that consists of two chains, linked by three disulfide s on

-Insulin binding -How is the activation loop phosphorylated?

* the two subunits move together to surround one insulin molecule, the kinase domains also draw closer together.

* the two subunits forced together, the kinase domain catalyze the phosphoryl groups from ATP to tyrosine residues in the activation loops -- conformational change takes place – active conformation

* pleckstrin homology domain: binds phosphoinositide lipids

* phosphotyrosine-binding domain

* ðanchoring the IRS protein to the insulin receptor and the membrane

* Src homology 2 (SH2) domains bind to specific phosphotyrosine domains in the IRS protein.

* Lipid kinases (also called phosphoinositide 3-kinase; PI3Ks ) function on phosphorylate PIP₂ to PIP_3..

* PDK1 activates another protein kinase Akt .

* Akt not membrane anchored, and moves through the cell to phosphorylates targets.

* control the trafficking of the glucose receptor GLUT4 to the cell surface.

* target enzymes that stimulate glycogen synthesis.

Insulin signaling is terminated by the action of phosphatases