Editing Nucleoside triphosphate (section)

=== GTP signal transduction ===
GTP is essential for [[signal transduction]], especially with [[G protein]]s. G proteins are coupled with a cell membrane bound receptor.<ref name=gpcr14047471/> This whole complex is called a [[G protein–coupled receptor|G protein-coupled receptor]] (GPCR). G proteins can bind either GDP or GTP. When bound to GDP, G proteins are inactive. When a [[ligand]] binds a GPCR, an [[Allosteric regulation|allosteric]] change in the G protein is triggered, causing GDP to leave and be replaced by GTP.<ref name=":3">{{Cite encyclopedia|url=https://www.britannica.com/science/G-protein-coupled-receptor|title=G protein-coupled receptor (GPCR) {{!}} biochemistry|encyclopedia=Encyclopedia Britannica|access-date=2017-11-12}}</ref> GTP activates the alpha subunit of the G protein, causing it to dissociate from the G protein and act as a downstream effector.<ref name=":3" />