Cytokinesis

Cytokinesis can be broadly classified into two types: animal cytokinesis and plant cytokinesis. The different types of cytokinesis are driven by different mechanisms and rely on different molecular machinery. Let us look at each type of cytokinesis in detail.

Animal Cytokinesis:
Animal cytokinesis is dependent upon the formation of a contractile ring made up of actin filaments and myosin proteins. This ring forms around the cell’s equator, and as it contracts, it pinches the cell membrane until it eventually separates into two daughter cells. The contractile ring is regulated by a complex of proteins called centralspindlin, which binds to the microtubules that had earlier been formed during mitosis.

Plant Cytokinesis:
Plant cytokinesis, unlike animal cytokinesis, does not involve the formation of a contractile ring. Instead, it relies on the formation of a cell plate – an organelle-like structure that forms on the equatorial plane of the cell. The cell plate is formed by the endoplasmic reticulum and Golgi vesicles, which deliver cell wall material to the site of cell division. As the cell plate grows, it eventually seals off the parent cell, forming two identical daughter cells.

While the mechanisms for cytokinesis in animals and plants differ significantly, they both rely on microtubules and microfilaments for proper function. Microtubules form a scaffold-like structure that helps define the location of the cytokinetic plane while microfilaments, such as actin, provide the force necessary for cell division.

Cytokinesis is also regulated by a class of proteins known as Rho family GTPases. These proteins control numerous aspects of cytokinesis, including the positioning and contraction of the contractile ring in animal cytokinesis and the delivery of Golgi vesicles in plant cytokinesis.

Failure in cytokinesis can have serious consequences for both the cell and the organism as a whole. Mutations in the genes that regulate cytokinesis can lead to the development of diseases such as cancer, where uncontrolled cell division is a hallmark of the disease.

Cytokinesis has also been subject to intensive research over the years to understand the mechanisms that dictate proper cell division. For instance, cytokinesis research has identified key proteins responsible for the formation of the contractile ring in animal cytokinesis, such as anillin, septins, and centralspindlin.

In conclusion, cytokinesis is a crucial process in cell division that involves the separation of one cell into two identical daughter cells. Proper cytokinesis relies on the well-coordinated action of many proteins and organelles, including microtubules, contractile rings, and cell plates. In light of the importance of cytokinesis in health and disease, many researchers are turning towards developing new treatments that target cytokinesis proteins and processes to prevent the onset of diseases such as cancer.