What is the difference between myosin and kinesin

Myosin II is the first identified myosin and it has two light chains and two heavy chains with motor domains. The myosin II motor proteins are responsible for muscular contraction. The non-muscle myosin II is responsible for cell division during cytokinesis. Figure 2: Myosin Associated Actin. Another type of myosin called myosin V is responsible for organelle and vesicle transport.

Myosin XI is responsible for cytoplasmic streaming. Kinesin refers to an ATPase similar to dynein that functions as a motor protein in the intracellular transport especially of cell organelles and molecules as mitochondria and proteins along microtubules. Myosin refers to a fibrous protein which forms together with actin the contractile filaments of muscle cells, in addition to involving in motion in other types of cell.

Thus, these definitions explain the fundamental difference between kinesin and myosin. The main difference between kinesin and myosin is that kinesin moves along microtubules of the cytoskeleton while myosin moves along the actin microfilaments.

Kinesin is important for the formation of the spindle apparatus while myosin is important for cell motility, cell division, and muscular contractions. Hence, this is another difference between kinesin and myosin. Kinesin is a type of motor protein, which moves along microtubules with their cargo. It especially involves the formation of the spindle apparatus.

On the other hand, myosin is another type of motor protein. It moves along the actin microfilaments. Generally, myosin is responsible for the muscular contractions and cell motility. Therefore, the main difference between kinesin and myosin is the type of molecular tracks they use for the movement and their role. Molecular Motors: Kinesin, Dynein and Myosin. Philadelphia: Lippincott-Raven; Available Here. The movement of these motor molecules is powered by the breakdown of the universal energy molecule called as ATP — Adenosine tri phosphate.

Both Kinesin and myosin are responsible for active transport of cell nutrients carbohydrates, proteins, fats , membrane bound organelles and vesicles within the cellular cytoplasm. High resolution electron microscopy has helped to identify certain structural and functional differences between Kinesin and Myosin.

The molecules are seen to differ in binding site, ATPase sites and cargo binding sites. Kinesin is the most common motor protein found in all vertebrates. It occurs in both neuronal and non-neuronal cells. It is a thin rod shaped protein around 80nm in length, with two globular heads connected to a fan like tail by a long stalk.

The Kinesin motor molecule moves along microtubules by interacting with the tubular protein. It moves towards the plus end of the microtubule that is away from the centre and towards the periphery of the cell. So we can say that Kinesin carries cargo towards the cell periphery.

Kinesin is responsible for fast axonal transport, formation of spindle apparatus and separation of chromosomes during mitosis and meiosis and transport of membrane bound organelles. It is also involved in constituting the membrane that lies between the Golgi complex and endoplasmic reticulum. But it does not constitute the membranes of these two organelles. Kinesin deficiency can cause Charcot Marie tooth syndrome and kidney diseases. Myosin is a motor protein that is found in muscle cells as well as other normal cells.

It looks like a double headed arrow with the two sets of heads pointing away from each other. Myosin moves along microfilaments by interacting with actin protein.

It is also known as contractile protein as it helps in muscle contraction. It is also vital for cell division and cytoplasmic streaming. Deficiency of Kinesin can cause Myopathies, Usher syndrome and deafness.

To summarise we can say that Kinesin and myosin belong to the molecular motor protein family. They aid in cellular and molecular transport of nutrients, metabolic products, organelles and vesicles by walking on tracks formed by the cytoskeleton. Rate this post!