Editing GTPase (section)

==Functions==
GTPases function as molecular switches or timers in many fundamental cellular processes.<ref name="pmid3113327">{{cite journal |last1=Gilman |first1=AG |date=1987 |title= G proteins: transducers of receptor-generated signals |journal= Annual Review of Biochemistry |volume=56 |pages=615–649 |doi=10.1146/annurev.bi.56.070187.003151 |pmid=3113327 }}</ref>

Examples of these roles include: 
* [[Signal transduction]] in response to activation of cell surface receptors, including [[G protein-coupled receptor|transmembrane receptor]]s such as those mediating [[taste]], [[Olfaction|smell]] and [[visual perception|vision]].<ref name="pmid3113327"/>
* [[Protein biosynthesis]] (a.k.a. [[translation (biology)|translation]]) at the [[ribosome]]. 
* Regulation of cell [[cellular differentiation|differentiation]], [[cell growth|proliferation]], [[cell division|division]] and [[cell migration|movement]]. 
* [[Protein targeting#Protein translocation|Translocation]] of [[protein]]s through [[cell membrane|membrane]]s. 
* Transport of [[vesicle (biology)|vesicle]]s within the [[cell (biology)|cell]], and vesicle-mediated secretion and uptake, through GTPase control of vesicle coat assembly.

GTPases are active when bound to GTP and inactive when bound to GDP.<ref name="pmid3113327"/><ref name="pmid7579038">{{cite journal |last1=Rodbell |first1=M |date=1995 |title=Nobel Lecture: Signal transduction: Evolution of an idea |journal=Bioscience Reports |volume=15 |issue=3 |pages=117–133 |doi=10.1007/bf01207453 |pmid=7579038 |s2cid=11025853 |pmc=1519115 }}</ref> In the generalized receptor-transducer-effector signaling model of [[Martin Rodbell]], signaling GTPases act as transducers to regulate the activity of effector proteins.<ref name="pmid7579038"/> This inactive-active switch is due to conformational changes in the protein distinguishing these two forms, particularly of the "switch" regions that in the active state are able to make protein-protein contacts with partner proteins that alter the function of these effectors.<ref name="pmid8462668"/>