Cytokinesis in many eukaryotes requires the formation and contraction of an actomyosin ring. This process has been well studied in Schizosaccharomyces pombe, where three myosins are involved: type II myosins Myo2 and Myp2 and type V myosin Myo51. Previous work defined precise role for each of these myosins in cytokinesis, recognizing Myo2 as mainly involved in actomyosin ring assembly, supported by Myo51, and Myp2 largely contributing to actomyosin ring contraction. In this work, by using the mis-sense mutant myo2-E1 and deletion mutants of myp2 and myo51, we investigated the contribution of each myosin to actomyosin ring formation and contraction. Our results proved that Myo2 is the major myosin contributing to each cytokinetic phase whereas Myo51, and more importantly Mpy2, were play secondary roles in actomyosin ring formation and contraction, respectively. We also provided insight into the function and structure of type II myosin Myo2 through the characterization of several myosin's mutations. Initially we identified the molecular basis of the cytokinetic defects present in myo2-E1 through the characterization of myo2-E1- Sup2, a suppressor capable to restore actomyosin ring contraction in myo2-E1. Next, we studied two additional mutations of myosin II, myo2-S1 and myo2-S2, both able to suppress cytokinetic defects in the temperature sensitive mutant of profilin cdc3-124. Finally, we optimized genetic code expansion in the lab in order to understand how multiple components act together at the cell division site, spatially and temporally, to ensure the proper contraction of the actomyosin ring at the end of cell cycle. In this work we applied this technique to initially map the interaction region between tropomyosin and actin at the level of amino acids. Additionally, we used this technology as an alternative method to fluorescently label a protein of interest without influencing its function.