Signal Transduction

Signal Transduction 1.    Norepinephrine/epinephrine bind to the g-protein (alpha-2) receptor resulting in a confirmational change. 2.    This change causes the alpha subunit of the receptor to bind with andenlyl cyclase. Before binding, adenlyl cyclase is an inactivated enzyme, once the alpha subunit binds with adenlyl cyclase it becomes activated. 3.    The activated adenlyl cyclase can then convert ATP into cAMP. (cAMP is a secondary messenger) 4.    cAMP targets protein kinase. (protein kinase is made up of 2 regulatory subunits and 2 catalytic subunits, when these subunits are attached to one another protein kinase is inactivated.) 5.    cAMP binds to the regulatory portions of protein kinase and causes release of the catalytic portions. 6.    These catalytic portions then result in a cascade of energy, they become activated when they pick up ATP. 7.    The activated form of protein kinase then causes protein phosphorylation. 8.    Response is produced.

Phospholipase C Pathway 1.    Norepinephrine/epinephrine bind to the G-protein (alpha-1) receptor resulting in a confirmational change. 2.    G subunit binds with phospholipase C. 3.    Phospholipase C causes the splitting of PIP2 into IP3 and DAG. 4.    IP3 causes the release of calcium ions (Ca2+) from endoplasmic reticulum. 5.    DAG activates protein kinase C along with the Ca2+/calmodulin complex. 6.    Protein kinase C phosphorylates proteins that go on to generate a response.

New Page