Question

Briefly describe the cytoskeletal structure and biological function of motile cilia why do we need to study the bending properties of single cilia?

Answer 1

The cytoskeletal structure and biological function of motile cilia:

Inside cilia, a microtubule-based cytoskeleton is present that is called as the axoneme. The axoneme of a motile cilium has two central microtubule singlets in addition to the nine outer doublets (that is called as a 9+2 axoneme). The axonemal cytoskeleton acts as a scaffolding for various protein complexes. A membrane like the plasma membrane is present outside of cilia, but compositionally distinct due to a blocking ring (necklace) around the base. In addition, it is distinct in nature by its population of receptors and other integral proteins. The dynein in the axoneme is responsible to form bridges between the neighbouring microtubule doublets. When ATP activates the motor domain of dynein, it attempts to walk along the adjoining microtubule doublet. The force generated by dyenin is converted into a bending motion. The building blocks of the cilia such as tubulins and other partially assembled axonemal proteins are added to the ciliary tips which point away from the cell body.

Cilia are responsible to move liquid past the surface of the cell. For single cells, it enables them (cells) to swim.

When ATP activates the motor domain of dynein, it attempts to walk along the adjoining microtubule doublet. This is responsible to force the adjacent doublets to slide over one another if not for the presence of Nexin between the microtubule doublets. Therefore, the force generated by dyenin is converted into the bending motion. This bending motion is responsible for the detection of locomotion (the ciliary movement) of certain organisms.