Sitokineze özgü fosfoproteinlerin niceliksel ve ağsal analizi

Nuclear division (mitosis) phosphorylation events have been characterized extensively however phosphorylation events taking place during cytoplasmic division (cytokinesis) specific phosphoproteins and responsible kinases are not well characterized. Our mass spectrometry analysis revealed ~1500 phosphorylation events that are specific to cytokinesis. We identified responsible kinases that are active during cytokinesis using a kinase-substrate prediction algorithm on our dataset. Including previously known cell cycle regulator kinases such as MAPK, CDK1/2 and Aurora, total 31 kinases were predicted to be active during cytokinesis. We also identified phosphorylation sites that are only present during cytokinesis in MKI67 protein which is previously reported as proliferation marker. MKI67 localizes to chromosomes during mitosis, acting as a surfactant preventing chromosome condensation during mitosis. These phosphorylation sites are found in N terminus successive repeat domains with unknown function. We suggest that cytokinesis specific phosphorylation of MKI67 might be important for its function in cell division during cytoplasmic division. Lastly, we compared evolutionary conservation scores of phosphorylation sites that are specific to monopolar and bipolar cytokinesis to understand if differing phosphorylation events between two models are crucial. We observed no significant difference between two models, meaning monopolar cytokinesis specific phosphorylation events are not redundant.