Gs alpha subunit

Gs alpha subunit

File:G protein cycle.svg

The Gs alpha subunit is part of the G protein cycle.

The Gs alpha subunit (Gαs) is a protein that in humans is encoded by the GNAS gene. It is a component of the G protein complex, which plays a crucial role in cell signaling and cellular communication.

Structure

The Gs alpha subunit is a GTP-binding protein that consists of 394 amino acids. It is part of the larger G protein complex, which also includes the beta and gamma subunits. The Gs alpha subunit is responsible for activating the adenylate cyclase enzyme when a G protein-coupled receptor (GPCR) is stimulated by a ligand.

Function

The primary function of the Gs alpha subunit is to transmit signals from GPCRs to other parts of the cell. When a ligand binds to a GPCR, it causes a conformational change in the receptor, which allows the Gs alpha subunit to exchange GDP for GTP. This activates the subunit, which then dissociates from the beta and gamma subunits and binds to adenylate cyclase, activating the enzyme. This leads to an increase in the production of cyclic AMP (cAMP), a second messenger that plays a key role in many cellular processes.

Clinical significance

Mutations in the GNAS gene that encodes the Gs alpha subunit can lead to a variety of diseases, including McCune-Albright syndrome, pseudohypoparathyroidism, and Albright's hereditary osteodystrophy. These conditions are often characterized by hormone resistance and abnormal bone development.

See also

• G protein
• G protein-coupled receptor
• Adenylate cyclase
• Cyclic AMP