# What are the components of the thin filaments of a muscle cell?

Feb 18, 2018

Actin, Tropomyosin and troponin.

#### Explanation:

Thin filament which is 7-8nm" in diameter is one of the two filaments vital for muscular contractions. It is composed of three proteins that are:

• Actin $\to$ The thin filaments are composed chiefly of actin proteins. That's why these filaments are also called as actin filaments. The actin molecules are arranged in to chains. This chains twist around each other like twisted double strand of pearls.

• Tropomyosin $\to$ Two strands of another protein twist around actin, This protein is tropomyosin.

• Troponin $\to$ This is another protein in thin filament. It is actually $3$ polypeptide complex: $\text{troponin I, troponin C & troponin T}$. Out of these: troponin I binds to actin and troponin T binds to tropomyosin. Troponin C binds calcium ions$\left(C {a}^{2 +}\right)$ in order to start muscle contraction.