The actin-binding proteins regulate microfilament turnover in a eukaryotic system.

Match the actin-binding protein (in column I) with their functions (in column II):

​Column I​​	​Column II​
​A. Cofilin​	​(i) binds ADP-G-actin and catalyzes the exchange of ADP for ATP​
​B. Profilin​	​(ii) binds preferentially to filament containing ADP-actin​
​C. Thymosin​	​(iii) assembles unbranched filament​
​D. Formin​	​(iv) binds to ATP-G-actin and inhibits addition of actin subunit to filament​

​Choose the CORRECT combination from below:​

Correct option is C

Explanation-

A. Cofilin – Binds to ADP-actin filaments and enhances depolymerization.

→ ii. binds preferentially to filament containing ADP-actin
​
B. Profilin – Binds G-actin (ADP-bound), catalyzing the exchange of ADP for ATP.
→ i. binds ADP-G-actin and catalyzes the exchange of ADP for ATP
​
C. Thymosin – Sequesters ATP-G-actin and prevents its addition to filaments.
→ iv. binds to ATP-G-actin and inhibits addition of actin subunit to filament

D. Formin – Promotes assembly of unbranched actin filaments.
→ iii. assembles unbranched filament

Correct Match:
A → ii
B → i
C → iv
D → iii

So, the correct answer is option C -A-ii, B-i, C-iv, D-iii