Microtubule cytoskeleton utilizes some accessory proteins to regulate microtubule dynamics.

Accessory proteins are given in column X and their typical functions in column Y.

Column X Accessory protein		Column Y Function
A.	$$γ$$​-TuRC	I.	Stabilizes plus end, promotes rapid microtubule growth
B.	XMAP215	II.	Helps in microtubule branching
C.	Katanin	III.	Nucleates assembly and remains associated with the minus and
D.	Augmin	IV.	Severs microtubules

​Which one of the following options represents all correct matches between Column X and Column Y? ​

Correct option is B

Explanation:

• A. γ-TuRC

  • γ-TuRC (gamma-tubulin ring complex) is crucial for microtubule nucleation. It forms a ring structure that assists in the assembly of microtubules at the minus end. It doesn't stabilize the plus end or promote growth directly, so the correct match is (iii) (nucleates assembly and remains associated with the minus end).

• B. XMAP215

  • XMAP215 plays an important role in stabilizing the plus ends of microtubules and promoting their rapid growth. Thus, it matches (i) (stabilizes the plus end and promotes rapid microtubule growth).

• C. Katanin

  • Katanin is a protein that severes microtubules, making (iv) (severs microtubules) the correct function associated with it.

• D. Augmin

  • Augmin is involved in promoting the branching of microtubules, so (ii) (helps in microtubule branching) is the correct function.

Information Booster:

1. γ-TuRC is essential for microtubule nucleation and helps form the minus end of the microtubule structure, guiding its growth.

2. XMAP215 is a microtubule-associated protein that enhances the polymerization of microtubules and stabilizes their plus end.

3. Katanin is a microtubule-severing enzyme, essential for controlling microtubule dynamics by severing them during cellular processes.

4. Augmin plays a significant role in branching microtubules and influencing their growth by assisting in the initiation of new microtubules.