Gq alpha subunit

Gq alpha subunit is a type of G protein that is involved in various cellular processes. It is a part of the G protein-coupled receptor system, which is responsible for transmitting signals from various stimuli outside a cell to its interior.

Etymology

The term "Gq alpha subunit" is derived from the nature of the protein. "G" stands for guanine nucleotide-binding protein, "q" refers to the specific type of G protein, and "alpha subunit" refers to the specific part of the G protein that this term refers to.

Function

The Gq alpha subunit is a part of the larger G protein complex. When a ligand binds to a G protein-coupled receptor, it causes a conformational change in the receptor, which allows it to act as a guanine nucleotide exchange factor (GEF). The GEF activity of the receptor causes the Gq alpha subunit to release its bound GDP and bind GTP instead. This exchange of GDP for GTP causes the Gq alpha subunit to dissociate from the beta and gamma subunits of the G protein. The Gq alpha subunit, now free to move within the membrane, can then interact with its target proteins and cause a cellular response.

Clinical significance

Mutations in the Gq alpha subunit can lead to various diseases. For example, a mutation that causes the Gq alpha subunit to be constitutively active (i.e., it is always turned on, regardless of whether a ligand has bound to the receptor) can lead to uveal melanoma, a type of eye cancer.

Related terms

• G protein
• G protein-coupled receptor
• Uveal melanoma

See also

• G protein-coupled receptor
• Signal transduction
• Cell signaling