Concept #1: G protein-Coupled Receptors

Concept #2: 3 Essential Components of GPCR Signal Transduction

Practice: A G protein-coupled receptor is comprised of ____ transmembrane α-helix/helices:

Practice: G protein-coupled receptors (GPCRs) are transmembrane proteins with ligand binding sites on the extracellular side of the membrane (near its N-terminal). What is the role of the G-protein in the GPCR signaling pathway?

Concept #3: Stimulatory vs. Inhibitory G Proteins (Gs vs Gi)

Practice: Gi is the inhibitory G protein of various effector enzymes. If a toxin released from a bacterial infection enters cells & covalently modifies the α-subunit of Gi so that it can no longer bind GTP, which of the following is a likely result?