Difference Between Actin and Myosin (With Table)

In the human body, muscles play a very important role in carrying out the day today’s activities. These muscles are composed of proteins, fibers such as microfibrils, which are cylindrical bundles with two types of filaments called Actin and Myosin.

The difference between Actin and Myosin is that Actin forms thin filaments in muscle fibers whereas Myosin forms thick filaments in muscle fibers.

Actin vs Myosin

The main difference between Actin and Myosin is that Actin helps in cell motion and cell division. On the other hand, Myosin generates force in skeletal muscles through a power to process and release energy from ATP hydrolysis, which helps in muscle contraction.

Actin is the multifunctional protein that forms microfilaments in the cytoskeleton, which links protein filaments that are present in the cytoplasm and also thin filaments in other muscle fibrils. Actin comes in two forms I.e Global actin and Fibrous actin, Actin is found in all the eukaryotic organisms in the world.

Myosin is also called motor protein which helps in muscle contraction, growth and tissue formation, metabolism, etc. Myosin effectively allows rapid entry of different viruses in eukaryotes by microbial pathogens such as bacterial parasites.

Comparison Table Between Actin and Myosin

Parameters Of ComparisonActinMyosin
DefinitionActin is the multifunctional globular protein that helps in cell motion and cell division in the body thus providing mobility to the body.Myosin is also called motor protein and with help of Actin protein, it helps in muscle contraction in the human body.
Found InActin proteins are found in the A and I bands of the sarcomere.Myosin proteins are found in the A band of the sarcomere.
SizeActin proteins are short. I.e 0.005 in diameter and 2.26m in length.Myosin proteins are longer filaments I.e 0.01 in diameter and 4-5 m in length.
SurfaceActin proteins have a smooth surface.Myosin protein has a rough surface.
Cross BridgesThere are no cross Bridges seen in Actin Filament.Myosin filaments, form bridges.

What is Actin?

Actin is a popular multifunctional globular protein found in eukaryotic cells and helps in cell motion cell and cell division thus providing mobility to the body.

Actin is a partial subdivision of the other two types of filaments in the cell. G actin I.e Globular Actin and F Actin I.e Filamentous Actin. Both the G Actin and F Actin are important for cellular functions like cell division, mobility, and contractions of cells.

Acting proteins are found in the A and I bands of the sarcomere. Actin proteins are short. I.e 0.005 in diameter and 2.26m in length.There are no cross Bridges seen in Actin Filament.The actin surface is smooth.

The primary role of Actin in cells is to form long chains, called filaments, that contribute to various functions of cell structure, cell migration, and cell replication. cells. Actin is a protein found in the cytoplasm and nucleus of eukaryotes. Actin is abundantly found in most of the cells and is comprised of 1 to 5 percent of the total protein mass of the cells, and 10% of the muscle cells in our body.

Many diseases in eukaryotes are also caused by allelic mutations in genes that allow the production of Actin or other related proteins. Mutations in non-identical genes that allow the body to produce Actin that cause muscle disease, deafness, and uneven changes in measurements and heart function in humans.

What is Myosin?

Myosin is called motor protein and with the help of Actin protein, it helps in muscle contraction and other mortality processes in eukaryotic organisms.

Myosin proteins are found in the A band of the sarcomere. Myosin proteins are longer filaments I.e 0.01 in diameter and 4-5 m in length. Myosin filaments form bridges and have a rough surface.

The full structure of Myosin protein is divided into three parts, Head, neck, and tail. The head region links filamentous actin and uses ATP hydrolysis to generate a force to travel with the filament towards the plus end. The neck part act as a link, as a lever arm that helps to convert the force generated by the action of the catalytic motor. The neck part of protein also helps in binding sites of myosin light chains. And lastly, the tail part of the protein helps in managing motor activities.

Main Differences Between Actin and Myosin

  1. Actin proteins are multifunctional globular proteins that help in cell division and also in providing mobility to the body whereas Myosin is called motor protein and with the help of Actin protein, which aids in muscle contraction.
  2. Actin protein is thinner and also shorter in size as compared to Myosin protein.
  3. The surface of Actin protein is observed smooth whereas myosin protein has a rough surface.
  4. Actin protein is located in cell walls, cell membrane, muscle fiber, and also in muscle microfilaments. On the other hand, Myosin is located in muscle cells.
  5. Actin proteins are large in number whereas myosin proteins are sparse in quantity.

Conclusion

Our body motion is completely dependent on muscle cells. For any kind of movement filament present in a muscle cell need to produce proteins such as Actin and Myosin.

Actin and Myosin are both proteins interdependent for muscle contraction. The role of Actin is to carry out cell division, while Myosin converts chemical energy into mechanical energy. Myosin generates force in skeletal muscles through a power to process and releases energy from ATP hydrolysis, which helps in muscle contraction.

References

  1. https://www.tandfonline.com/doi/pdf/10.3109/10409237409105443
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/pmc1150189/