Q12.2-6CC. - Campbell Biology

Question

What other functions do actin and tubulin carry out? Name the proteins they interact with to do so. (Review Figures 6.21a and 6.26a.)

 

Figures 6.21a:

 

Figures 6.26a:

 

Step-by-Step Solution

Answer

Actin and tubulin are the main components of cytoskeleton that provide shape to the cell and help in the movement of cell organelles within the cell. For this purpose, tubulin organizes into microtubules that move the vesicles and other cell organelles by interacting with other motor proteins. 

 

Actin forms microfilaments that help in muscle contraction by interacting with myosin filaments. 

Step 1: Actin and Tubulin

Many filamentous proteins like actin and tubulin are the main structural components of animal cells. Tubulin proteins make microtubules that are the largest filaments found in the cells. Actin proteins are components of actin filaments that are the smallest.

Step 2: Interaction of actin with proteins

Actin filaments interact with myosin to help in muscle contraction. The walking of myosin projections makes the actin and myosin filaments move that cauing the shortening of muscle cells.

Coordinated shortening of muscles cells allows contraction of the muscles. Actin, when interacting with proteins, helps in cytoplasmic streaming.

Step 3: Interaction of tubulin with proteins

Microtubules are hollow rod-like structures made up of many tubulins. Microtubules give shape and mechanical support to the cells and act as tracks on which organelles that have motor proteins attached with them can move. 

Also, they help in the movement of vesicles during the transport of synthesized materials from the Endoplasmic reticulum to the Golgi body and from there to the plasma membrane.