5 Stages Of Cleavage Furrow Formation

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The process of cell division is a complex and highly regulated process that is essential for growth, development, and maintenance of tissues in multicellular organisms. One of the critical stages of cell division is the formation of the cleavage furrow, which is a specialized structure that forms in the center of the cell and eventually leads to the separation of the cell into two daughter cells. In this article, we will explore the 5 stages of cleavage furrow formation and discuss the key mechanisms and regulators involved in this process.

Stage 1: Initiation of Cleavage Furrow Formation

The first stage of cleavage furrow formation is initiated during the anaphase stage of mitosis, when the chromosomes have separated and are moving towards the poles of the cell. At this point, the cell begins to prepare for the formation of the cleavage furrow by activating a series of signaling pathways that will eventually lead to the contraction of the actomyosin ring. One of the key regulators of this process is the protein kinase C (PKC), which is activated by the small GTPase RhoA. PKC then phosphorylates and activates the myosin light chain kinase (MLCK), which in turn phosphorylates and activates the myosin II protein.

Key Players: PKC, RhoA, MLCK, Myosin II

Stage 2: Assembly of the Actomyosin Ring

The second stage of cleavage furrow formation involves the assembly of the actomyosin ring, which is a specialized structure composed of actin filaments and myosin II proteins. The actomyosin ring forms in the center of the cell and is anchored to the plasma membrane by a series of proteins known as the septins. The assembly of the actomyosin ring is regulated by a series of proteins, including the formin protein, which is responsible for nucleating actin filaments, and the anillin protein, which is responsible for recruiting myosin II to the actomyosin ring.

Key Players: Formin, Anillin, Septins

Stage 3: Contraction of the Actomyosin Ring

The third stage of cleavage furrow formation involves the contraction of the actomyosin ring, which is driven by the myosin II proteins. The contraction of the actomyosin ring generates a force that pulls the plasma membrane inward, forming the cleavage furrow. The contraction of the actomyosin ring is regulated by a series of proteins, including the Rho-associated protein kinase (ROCK), which phosphorylates and activates the myosin light chain kinase (MLCK), and the protein phosphatase 1 (PP1), which dephosphorylates and inactivates the myosin light chain.

Key Players: ROCK, MLCK, PP1

Stage 4: Membrane Ingrowth and Furrow Deepening

The fourth stage of cleavage furrow formation involves the ingrowth of the plasma membrane into the cleavage furrow, which is driven by the contraction of the actomyosin ring. As the plasma membrane ingrows, the cleavage furrow deepens, eventually forming a narrow, tubular structure that separates the two daughter cells. The membrane ingrowth is regulated by a series of proteins, including the dynamin protein, which is responsible for fission of the plasma membrane, and the syntaxin protein, which is responsible for fusion of the plasma membrane.

Key Players: Dynamin, Syntaxin

Stage 5: Completion of Cytokinesis

The final stage of cleavage furrow formation involves the completion of cytokinesis, which is the process of cell division. As the cleavage furrow deepens, the actomyosin ring continues to contract, eventually leading to the separation of the two daughter cells. The completion of cytokinesis is regulated by a series of proteins, including the Aurora B kinase, which is responsible for regulating the activity of the actomyosin ring, and the polo-like kinase (PLK), which is responsible for regulating the activity of the septins.

Key Players: Aurora B, PLK

In conclusion, the 5 stages of cleavage furrow formation are a complex and highly regulated process that is essential for cell division. Understanding the key mechanisms and regulators involved in this process is crucial for understanding the underlying biology of cell division and for developing new therapeutic strategies for the treatment of diseases such as cancer.

We hope this article has provided you with a comprehensive understanding of the 5 stages of cleavage furrow formation. If you have any questions or comments, please feel free to share them below.