Question

The transmission of G-protein-coupled receptors involves only two steps: binding to the receptor protein and activation of G-proteins. True or false?

Answer 1

Answer:

False

Explanation:

G-Protein Coupled Receptors (GPCR):

GPCRs are transmembrane receptors with three components:

1. Extracellular domain for ligand binding
2. Seven transmembrane helices
3. Intracellular G-protein binding domain

Transmission Through GPCRs:

1. A ligand binds to the extracellular domain of the GPCR.
2. The GPCR undergoes conformational changes.
3. This conformational change activates the G-protein by replacing its bound GDP (guanosine diphosphate) with GTP (guanosine triphosphate).
4. The G-protein then loses its GTP bound alpha subunit which activates the adenylyl cyclase system.