Encyclopedia of Cancer

Living Edition
| Editors: Manfred Schwab


  • Teresa Gómez Del Pulgar
  • Juan Carlos Lacal
Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-27841-9_2533-2



GTPases, also known as GTP-binding proteins, G-proteins, or small GTP-binding proteins, are members of the Ras superfamily. They are enzymes that catalyze the hydrolysis of GTP to GDP and inorganic phosphate. They are important intermediaries in signal transduction.

GTPases are proteins that work as molecular switches in the regulation of cell responses to extracellular signals. Their function is regulated by GDP/GTP cycling, where GDP/GTP exchange promotes formation of the GTP-bound protein and GTP hydrolysis promotes formation of the GDP-bound protein. The intrinsic GDP/GTP exchange and GTP hydrolytic activities are typically low and are further accelerated by regulatory proteins. For some GTPases, the GTP-bound form represents the active form (e.g., Ras and Rho family proteins), whereas for others GDP/GTP cycling is required for activity.


The function of GTPases is regulated by an alternating cycle of on/off states depending...


Exchange Factor Acceptor Compartment Human Genome Sequence Project Regulate Signaling Network Specific Intracellular Compartment 
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Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  • Teresa Gómez Del Pulgar
    • 1
  • Juan Carlos Lacal
    • 1
  1. 1.Instituto de Investigaciones Biomedicas, CSICMadridSpain