User:Gabeqnes26/sandbox

Signal Transduction Path
The glucagon receptor, upon binding with the signaling molecule glucagon, initiates a signal transduction pathway that begins with the activation of adenylate cyclase, which in turn produces cyclic AMP (cAMP). Protein kinase A, whose activation is dependent on the increase levels of cAMP, is responsible for the ensuing cellular response in the form of protein kinase 1 and 2. The ligand-bound glucagon receptor can also initiate a signaling pathway that is independent of cAMP, activating phospholipase C. Phospholipase C produces DAG and IP3 from PIP2, a phospholipid phospholipase C cleaves off of the plasma membrane. Ca2+ stores inside the cell release Ca2+ when its calcium channels are bound by IP3.

The glucagon receptor is a 62 kDa protein that is activated by glucagon and is a member of the class B G-protein coupled family of receptors, coupled to G alpha i, Gs and to a lesser extent G alpha q. Stimulation of the receptor results in the activation of adenylate cyclase and phospholipase C and in increased levels of the secondary messengers intracellular cAMP and calcium. In humans, thee glucagon receptor is encoded by the GCGR gene. A missense mutation at 17q25 in the GCGR gene is associated with diabetes mellitus type 2. Stimulation of the receptor results in the activation of adenylate cyclase and phospholipase C and in increased levels of the secondary messengers intracellular cAMP and calcium.