BIOL 300 Lecture Notes - Lecture 27: Glycogen, Lipid-Anchored Protein, Phosphodiesterase
16 Dec 2017
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Some one the 7- transmembrane domains change conformation. G-proteins contain three subunits : alpha, beta and gamma. G-alpha is a gtpase and modulates an effector upon ligand binding to gpcr. Effectors are ion channels or enzymes that produce second messengers (camp, cgmp, dag ) In the resting state, g proteins form a trimeric complex and g-alpha binds gdp. Amplification of response in the epinephrine > effector protein pathway: turn on many different processes, need little amount of epinephrine, easy to deliver : important for drugs. Termination of response > a pathway that is always on is bad for the body! Desensitization/adaptation: constant ligand stimulation results in phosphorylation of receptor at multiple sites by pka : galpha- Friday, november 17th: agonists : bind and activate a pathway, antagonist : bind and prevent the pathway. Many neurotransmitters like serotonin bind directly to ion channels (ligand-gates ion channels) Many others bind to cpcrs that either directly or indirectly regulate ion channels.
