Question

Consider a mutation in tubulin that alters how tubulin changes its conformation after GTP hydrolysis. More specifically, the mutation makes tubulin "stiffer" after GTP hydrolysis, such that the tubulin does not transition as quickly between the straight and curved conformations. How would microtubule dynamics be affected by this mutation? Select all that apply.

Question 5 options:

	a) Microtubules will grow faster (the net growth rate increases).
	b) Microtubules will shrink more slowly after a catastrophe (the "post-catastrophe shrinkage rate" is reduced).
	c) Microtubules will undergo fewer catastrophes (the "catastrophe frequency" will decrease).
	d) The GTP cap will be smaller

Answer 1

Mutation of GTP hydrolysis

b) Microtubules shrink slowly after a catasrope. Post catasrope shrinkage rate reduced.

c) microtubules shrinkage frequency reduces.

d)GTP cap becomes smaller.

When the microtubules grow normally., GTP is attached at protein end. This results in cap formation. Later when GTP -----> GTP cap shrinks. When cap is lost , rapid shrinkage occurs.When cap is gained normal growth occurs.After mutation, shrinkage rate reduces , catastrophe frequency reduces and cap size decreases.