In the process of signal transduction, what is typically activated after the α-subunit releases from the βɣ-complex?

In signal transduction involving G protein-coupled receptors (GPCRs), the activation of downstream signaling pathways begins with the binding of a ligand to the receptor. This interaction triggers a conformational change in the GPCR, facilitating the exchange of GDP for GTP on the α-subunit of the associated G protein. Once this exchange occurs, the α-subunit becomes activated and dissociates from the βɣ-complex.

Following this dissociation, the activated α-subunit can interact with various effector proteins, depending on its specific type. In the case of one common signaling pathway, the activated α-subunit stimulates adenylyl cyclase, leading to an increase in the production of cyclic AMP (cAMP) from ATP. cAMP serves as a critical second messenger in numerous signaling cascades, activating protein kinase A (PKA) and initiating a wide variety of cellular responses.

Therefore, the correct choice here is the activation of adenylyl cyclase. This mechanism exemplifies how the release of the α-subunit from the βɣ-complex serves as a pivotal step in propagating the signal within the cell, specifically through the production of cAMP.