Signal Transduction via Cell Membrane Receptors
Start with the big picture
The lesson surveys several cell-membrane receptor families and the pathways they activate. GPCRs couple ligand binding to G-protein signaling: Gs raises cAMP and activates PKA, Gi lowers cAMP, and Gq/11 promotes IP3, DAG, calcium release, and PKC activity. Other routes include RTK signaling through RAS-MAPK, PI3K-Akt, or PLCγ; JAK-STAT signaling from cytokine receptors; and Smad signaling through TGF-β/activin receptors. Receptor guanylyl cyclases generate cGMP, while ligand-gated ion channels alter membrane potential. Integrins also relay mechanical and chemical cues. The topic highlights signal cross-talk and mechanisms that limit signaling, including G-protein inactivation, phosphodiesterases, receptor phosphorylation, and β-arrestin-mediated internalization.
What you'll learn
- Describe how GPCR activation promotes GDP-to-GTP exchange on Gα.
- Distinguish the major Gs, Gi, Gq/11, and G12/13 signaling routes.
- Identify key signaling pathways associated with RTKs and cytokine receptors.
- Compare kinase-receptor, guanylyl-cyclase, and ligand-gated ion-channel signaling.
- Explain how signaling termination and cross-talk shape cellular responses.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
