Final answer:
Following the conformational shift in the alpha subunit during GPCR signaling, it dissociates from the beta and gamma subunits and activates effectors such as adenylate cyclase, leading to the production of second messengers like cAMP.
Step-by-step explanation:
After a conformational shift in the alpha subunit of the G protein occurs in GPCR signaling, the next step involves the alpha subunit's dissociation from the beta and gamma subunits.
This activated GTP-bound alpha subunit can then interact with various effectors, such as adenylate cyclase or phospholipase C, depending on the cell type and receptor involved. This leads to the generation of second messenger molecules like cAMP or the release of calcium ions, which amplify the signal and lead to diverse cellular responses.
A classic example is adenylate cyclase activation by the alpha subunit, which converts ATP to cAMP, initiating a phosphorylation cascade altering gene expression or leading to other effects such as muscle contraction or hormone release.