The cleavage furrow is the area of invagination of the cell surface that occurs during the process of cytokinesis. The cleavage furrow forms as a result of the assembly and subsequent constriction of an actin-myosin II ring, carefully positioned in the equatorial cell cortex and connected to the plasma membrane. The cleavage furrow and the underlying contractile ring continues to ingress to a diameter of 1-2 micrometers, leading to the formation of a cytokinetic bridge. Subsequent abscission of the dense midbody and membrane fusion, which usually appears hours later, marks the end of cytokinesis.
The cleavage furrow and the contractile ring are transient compartments that can be detected during a limited part of cytokinesis, the end of which is marked by the formation of a cytokinetic bridge. In the Cell Atlas, a specific staining of the contractile ring or the plasma membrane in the area of invagination is annotated as cleavage furrow.
Read more about the proteome of the cleavage furrow as a substructure of actin filaments.