G protein
noun
variants
or G-protein
ˈjē-ˈprō-ˌtēn 
-ˈprō-tē-ən
plural G proteins or G-proteins
: any of a class of cell membrane proteins that are coupled to cell surface receptors and upon stimulation of the receptor by an extracellular signaling molecule (such as a hormone or neurotransmitter) bind to GTP to form an active complex which mediates an intracellular event (such as activation of adenylate cyclase)
Cite this Entry
“G protein.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/G%20protein. Accessed 31 Oct. 2025.
Copy CitationMedical Definition
G protein
noun
variants
or G-protein
: any of a class of cell membrane proteins that are coupled to cell surface receptors and upon stimulation of the receptor by an extracellular molecule (as a hormone or neurotransmitter) bind to GTP to form an active complex which mediates an intracellular event (as activation of adenylate cyclase)
Love words? Need even more definitions?
Merriam-Webster unabridged
Share