Tsytokineesi

Tsytokineesi is a term used in some transliterations for the biological process more commonly called cytokinesis, the final stage of cell division in eukaryotic cells. It refers to the division of the cytoplasm to form two distinct daughter cells after chromosome segregation (karyokinesis).

In animal cells, cytokinesis typically begins during anaphase or telophase with the formation of a contractile actomyosin ring at the cell cortex. This ring constricts the plasma membrane, producing a cleavage furrow that ingresses and ultimately splits the cytoplasm. The final separation is achieved through abscission, a process involving membrane remodeling and, in many organisms, the ESCRT protein machinery and remnants of the central spindle/midbody.

In plant cells, the presence of a rigid cell wall requires a different approach. Vesicles derived from the Golgi apparatus coalesce at the center of the cell to form a cell plate, which enlarges outward to separate the two new cells. The cell plate eventually fuses with the existing cell membranes, creating two distinct cell walls.

Cytokinesis is tightly coordinated with mitosis and is controlled by cell cycle regulators and signaling pathways, including Rho family GTPases (such as RhoA), kinases, and components of the mitotic spindle. Proper execution ensures even distribution of cytoplasm and organelles; failures can lead to multinucleated cells or genomic instability and are associated with developmental defects and diseases such as cancer.

See also: mitosis, meiosis, cell cycle, cell division, cytokinesis-related machinery.