Which of the following is true regarding the GTPase activity of Ras proteins?
A) under normal conditions, the GTPase activity is very high with most Ras proteins kept in an inactive state
B) Ras proteins have no inherent GTPase activity and rely upon the binding of GTPase-activating protein
C) mutations of the Ras protein cause GTPase activity to be extremely low
D) the GTPase-activating protein is inhibited by cAMP
E) none of the above

Question

Quizplus · Accepted Answer

Mutations of the Ras protein often result in decreased GTPase activity, causing the protein to remain in an active state, which can lead to uncontrolled cell growth and potentially cancer. Option A is incorrect because under normal conditions, the GTPase activity of Ras proteins is low, allowing for activation by GTP binding. Option B is incorrect because Ras proteins do have intrinsic GTPase activity, although it is slow relative to other GTP-binding proteins. Option D is incorrect because the GTPase-activating protein is not regulated by cAMP.

Which of the Following Is True Regarding the GTPase Activity