One of the most important regulators that specify the cleavage plane is a protein complex known as centralspindlin, consisting of RacGAP50C and the Drosophila kinesin-6 protein, Pav. Centralspindlin is critical for both CS assembly and cytokinesis. It is associated with Pebble and targets this RhoGEF to the equatorial cortex. Pebble mediates the conversion of GDP-Rho1 to GTP-Rho1 and activates Rho1-dependent cascades at the equatorial cortex. Targeting of ECT2/Pebble to the cortex depends on the phosphorylation of MgcRacGAP/RacGAP50 by Plk1/Polo. The hypomorphic polo mutant of Drosophila showed defects in cytokinesis during male meiosis. Pav and Polo interact and depend on each other for localization on the CS in Drosophila embryos. The centralspindlin complex, consisting of RacGAP50C and Pav/MKLP-1, can localize the Pebble/RhoGEF on the equatorial cortex to initiate F-actin polymerization in order to construct the contractile ring. In addition, anillin plays an important role in the initiation and progression of cytokinesis. Anillin is known as a CR component that was first observed in the equatorial region in RG7112 cultured Drosophila and mammalian cells. Anillin binds F-actin, myosin II, and septins. This scaffold protein also binds Rho and RacGAP50C in somatic cells. Therefore, anillin has been considered as a key factor for maintenance of the actomyosin ring, which causes the ring to couple to CS MTs at anaphase. Furthermore, recent studies have reported that anillin depletion did not affect the recruitment of F-actin or myosin to the CF, although it was necessary for septin recruitment in yeast to mammalian cells. Several microtubule-associated proteins have also been described as essential factors for cytokinesis in Drosophila male meiosis. Feo, the Drosophila ortholog of PRC1, is specifically enriched at the CS mid-zone and is required for cytokinesis in spermatocytes. Orbit, a Drosophila ortholog of the conserved MAP family known as CLASP, is essential for proper organization of mitotic SH-4-54 spindles in early embryos, larval neuroblasts, and cultured cells.