Concept #1: Inhibitory Adenylate Cyclase GPCR Signaling

Practice: The addition of the nonhydrolyzable GTP-analog, GTPγS (shown below), is a common cell culture technique. If only affecting the inhibitory pathway, what effect would GTPγS have on cellular cAMP levels?

Practice: If a chemical is an inhibitor of the enzyme adenylyl cyclase, which of the following steps in the GPCR signaling pathway would be directly blocked?

Concept #2: GPCR Desensitization 

Example #1: What conclusion can be made from the results/data?

Practice: How does GPCR termination differ from GPCR desensitization?

Practice: Which of the following statements about beta-arrestin and GPCRs is TRUE?

Practice: Which of the following are involved in the desensitization of the β-adrenergic receptor?