Step I insulin receptor drama

[lilmisty]

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I've tried internet and searching previous posts buuuut I'm still really confused.

Insulin receptor--is it a MAP kinase pathway thing? Or a protein phosphatase thing? Or both? And do things like growth factors also follow the same pathways?

 

[thehundredthone]

Technically both. For example there is the action of insulin on glycogen regulation which takes place via protein phosphatases. There is also some feedback signalling via a MAP kinase phosphatase that dephosphorylates the MAP kinase when there is excess insulin signalling. For the USMLE, however, the answer MAP kinase because this is what directly affects downstream actions of insulin related to glucose metabolism. Other growth factors also follow the same signalling pathway.

Insulin signaling involves the transient activation/inactivation of various proteins by a cycle of phosphorylation/dephosphorylation. This dynamic process is regulated by the action of protein kinases and protein phosphatases. One family of protein kinases that is important in insulin signaling is the mitogen-activated protein (MAP) kinases, whose action is reversed by specific MAP kinase phosphatases (MKPs).