What is the Difference Between Cytoplasmic and Axonemal Dynein?

Cytoplasmic and axonemal dyneins are two different types of dynein proteins that play crucial roles in cellular processes. The main differences between them are:

1. Location: Cytoplasmic dynein is found in all animal cells and possibly in plant cells as well, while axonemal dynein is only found in cells that have structures like cilia and flagella.
2. Function: Cytoplasmic dynein is responsible for various cellular processes, such as organelle transport and centrosome assembly, and is necessary for cell survival. Axonemal dynein, on the other hand, causes the sliding of microtubules in the axonemes of cilia and flagella, which is essential for their beating.
3. Structure: Cytoplasmic dynein has a molecular mass of about 1.5 megadaltons (MDa) and is a dimer of dimers, containing approximately twelve polypeptide subunits. Axonemal dynein comes in multiple forms, containing either one, two, or three non-identical heavy chains (depending on the organism and location in the cilium).
4. Processivity: Cytoplasmic dynein is processive, meaning it can move along microtubules without detaching, while axonemal dynein is non-processive and causes the sliding of microtubules.

In summary, cytoplasmic dynein is a processive motor protein found in all animal cells, while axonemal dynein is a non-processive protein found only in cells with cilia and flagella. They have distinct functions and structures, with cytoplasmic dynein playing a role in cellular processes like organelle transport and centrosome assembly, and axonemal dynein being responsible for the beating of cilia and flagella.

Comparative Table: Cytoplasmic vs Axonemal Dynein

Cytoplasmic dynein and axonemal dynein are two types of dynein motor proteins that play crucial roles in different cellular processes. Here is a table highlighting the differences between them:

Cytoplasmic dynein is a processive motor protein that moves along microtubules and plays a role in intracellular transport and cell division. On the other hand, axonemal dynein is involved in the beating of cilia and flagella, causing the sliding of microtubules. The regulation of axonemal dynein activity is critical for the proper functioning of cilia and flagella.