What are some examples of effectors in GPCR signaling?

• A. Adenylyl Cyclase, phospholipases, and plasma ion channels
• B. DNA polymerase and ribosome
• C. Mitochondrial ATP synthase
• D. Nuclear transcription factors

Answer: (A)

In GPCR signaling, effectors are the proteins that the activated G protein directly interacts with to produce a cellular response. Classic targets include adenylyl cyclase, which converts ATP to the second messenger cAMP; phospholipase C, which cleaves PIP2 to generate IP3 and DAG; and plasma membrane ion channels, whose opening or closing alters ion flow and membrane potential. These effectors translate receptor activation into rapid changes inside the cell through second messengers and changes in ion flux. The other options aren’t direct GPCR effectors: DNA polymerase and ribosomes handle DNA replication and protein synthesis, mitochondrial ATP synthase makes ATP, and nuclear transcription factors are downstream responders rather than immediate membrane-bound targets of GPCR signaling.