What is the Difference Between Dynein and Kinesin

The main difference between dynein and kinesin is that dynein carries cargo like organelles and vesicles from the periphery to the center of the cell whereas kinesin carries cargo from the center to the periphery of the cell. Furthermore, dynein is important in sliding microtubules relative one another as well.

Dynein and kinesin are two types of motor proteins which use microtubules as their tracks. Microtubules are one of the three components of the cytoskeleton. The other two components of the cytoskeleton are actin and intermediate filaments.

Key Areas Covered

1. What is Dynein
     – Definition, Direction of Movement, Types, Function
2. What is Kinesin
     – Definition, Direction of Movement, Function
3. What are the Similarities Between Dynein and Kinesin
     – Outline of Common Features
4. What is the Difference Between Dynein and Kinesin
     – Comparison of Key Differences

Key Terms

Axonemal Dyneins, Cytoskeleton, Cytoplasmic Dynein, Kinesin, Microtubules, Motor Proteins

What is Dynein

Dynein is a type of motor protein that uses microtubules in the cytoskeleton to carry its cargo. It is a type of large motor protein. Since it carries its cargo towards the minus end of the microtubules, dynein is also called minus-end directed motor proteins. That means; dynein transports cargo from the periphery to the center of the cell. However, it uses chemical energy in ATP for its mechanical movement.

Figure 1: Cytoplasmic Dynein

The two types of dynein in the cell are cytoplasmic dyneins and axonemal dyneins. Cytoplasmic dyneins are responsible for the positioning of cellular organelles like Golgi apparatus. Also, they carry vesicles such as endosomes and lysosomes, which are produced by the endoplasmic reticulum. In addition, they are involved in positioning the mitotic spindle during cell division and are responsible for the movement of chromosomes.

Figure 2: Axonemal Dynein

Furthermore, axonemal dyneins occur in eukaryotic flagella and cilia. They form cross-bridges between two adjacent microtubules, allowing their sliding movement relative to one another.

What is Kinesin

Kinesin is another type of motor protein which also uses microtubules of the cytoskeleton to carry its cargo. The four main parts of the kinesin are the head, tail, stalk, and the tail. The head is the ATPase domain. Also, the head region binds to the microtubule while the tail binds to the cargo. Generally, kinesin molecule consists of two head groups which operate in a tandem manner; one head region binds to the microtubule, and then the other head region binds. Hence, this type of movement is called kinesin “walking”.

Figure 3: Kinesin

Moreover, kinesins are a type of positive end-directed motor proteins, which move from the negative to the positive end of the microtubule. Hence, kinesin carries their cargo from the center of the cell to its periphery.

Similarities Between Dynein and Kinesin

• Dynein and kinesin are two types of motor proteins.
• They use microtubules of the cytoskeleton as their tracks.
• Moreover, they carry cargo like organelles and vesicles throughout the cell.
• Also, both their movement is unidirectional.
• Besides, the function of both motor proteins requires energy in the form of ATP. Hence, both motor proteins contain an ATPase domain.

Difference Between Dynein and Kinesin

Definition

Dynein refers to a family of microtubule motor proteins, which regulates the movement of cellular organelles and structures, the beating of cilia and flagella, and the movement of chromosomes to the poles of the spindle while kinesin refers to another family of microtubule motor proteins similar to dynein, which functions as a motor protein in the intracellular transport, especially of cell organelles and molecules such as mitochondria and proteins along microtubules. Thus, this is the main difference between dynein and kinesin.

Also Called

Moreover, dynein is a negative end-directed motor protein while kinesin is a positive end-directed motor protein.

Direction of Movement

The direction of movement is a major difference between dynein and kinesin. Dynein carries their cargo from the periphery to the center of the cell while kinesin carries their cargo from the center of the cell to its periphery. 

Conclusion

Dynein is a type of motor protein that uses microtubules in the cytoskeleton to carry its cargo from the periphery to the center of the cell. On the other hand, kinesin is another type of motor protein which carries its cargo from the center to the periphery of the cell. And, this cargo can be organelles and vesicles. Moreover, dynein is also involved in the movement of flagella and cilia in eukaryotes. Therefore, the main difference between dynein and kinesin is their direction of movement.

References:

1. Berg JM, Tymoczko JL, Stryer L. Biochemistry. 5th edition. New York: W H Freeman; 2002. Section 34.3, Kinesin and Dynein Move Along Microtubules. Available Here

Image Courtesy:

1. “LIS1 NDE(L)1 Dynein” By © 2015 Jaarsma and Hoogenraad –  (CC BY 4.0) via Commons Wikimedia  
2. “Eukaryotic flagellum” By en:User:Smartse – File:Axoneme.JPG and Figure 19.28 on page 819 of “Molecular Cell Biology, 4th edition, Lodish and Berk” ISBN 0-7167-3706-X (CC BY-SA 3.0) via Commons Wikimedia  
3. “Actin kinesin walking” By Boumphreyfr – Own work (CC BY-SA 3.0) via Commons Wikimedia