01:694:301 Lecture Notes - Lecture 14: Signal Transduction, Adrenergic Receptor, Cyclic Adenosine Monophosphate

• School: Rutgers University
• Department: Molecular Biology and Biochemistry
• Course: 01:694:301
• Professor: F Deis

Document Summary

Contain 7 helices that span membrane bilayer; snakes through membrane 7x. Binding of ligand outside cell causes conformational change in 7tm receptor inside the cells. Ex: rhodopsin found in retina; senses photons and initiates signals for visual sensation. Epinephrine signaling begins with ligand binding to a protein called the -adrenergic receptor: epinephrine is hormone secreted by adrenal glands in respond to external or internal stressors. Adrenergic receptor and rhodopsin have similarities structurally: similar location found b/w rhodopsin 11-cis-retinal; -adrenergic receptor inhibitor carazolol, g-proteins activated by ligand binding of 7tm receptors. In inactivated state, g-proteins bound to gdp; in this form it exists as a heterotrimer consisting of , , and subunits: subunit is member of p-loop ntpase family and binds to nucleotide. The hormone-receptor catalyzes exchange of gtp for bound gdp. Interacts with g protein and opens nucleotide binding site for gtp in cell can displace gdp.