cytokinetic

Cytokinetic is an adjective used in cell biology to describe processes, structures, and events related to cytokinesis, the final stage of cell division in which the cytoplasm is partitioned to form two daughter cells after mitosis or meiosis. The term is often applied to describe mechanisms of cytoplasmic division in both animal and plant cells.

In animal cells, cytokinesis typically begins with the assembly of a contractile actomyosin ring at the cell cortex, guided by RhoA signaling. The ring contracts to form a cleavage furrow, ingresses the plasma membrane, and ultimately pinches the cell into two. In plant cells, cytokinesis occurs without a contractile ring; vesicles derived from the Golgi coalesce at the center to form a cell plate that expands outward until it fuses with the parental membranes, dividing the cytoplasm.

Molecular regulation involves a network of proteins that coordinate cytoskeletal dynamics and membrane remodeling. Key players include Rho family GTPases (especially RhoA), ECT2, the central spindle and midbody, Polo-like kinase 1, and Aurora B. Structural components include actin filaments, myosin II, anillin, and septins; vesicle trafficking and ESCRT-III–mediated abscission complete the separation in many cells.

Cytokinetic events are tightly timed with mitosis and meiosis. Failures or delays can produce binucleate or polyploid cells and contribute to genomic instability, with implications for development and cancer. The specifics of cytokinetic machinery can vary among organisms and cell types.