GTPases Serve in Many Signal Transduction Pathways and the Presence

Multiple Choice

GTPases serve in many signal transduction pathways and the presence of GTP or GDP dictates whether the pathway is on or off,respectively.Which of the following statements is TRUE regarding guanine nucleotide exchange factors (GEF) and the role in these signaling pathways?

A) They hydrolyze GTP into GDP and Pᵢ.
B) They decrease the GTPase activity of the G-protein.
C) They catalyze the dissociation of GDP on the G-protein and promote the replacement of GTP.
D) none of the above