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)

Word History

Etymology

guanosine triphosphate-binding protein

First Known Use

1975, in the meaning defined above

Medical Definition

G protein

noun

variants or G-protein

ˈjē- 

: 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)