Student Scholars Day

Phosphoregulation of Mid1 Association with Medial Cortex

Henry Hall Atrium 2

Phosphorylation events are the driving force of the cell cycle. During mitosis and cytokinesis, fission yeast scaffolding protein Mid1 changes phosphorylation states as it functions to anchor the contractile ring in the cell center. Here we seek to determine if phosphorylation regulates Mid1-membrane association. Cells were arrested at various cell cycle stages corresponding to hypo- and hyper-phosphorylated Mid1. Membrane flotation assays were preformed to detect Mid1 in complex with the cell membrane. We expect hyper-phosphorylated Mid1 to fraction with the cellular membrane while hypo-phosphorylated Mid1 separates with membrane free fractions. Preliminary results also suggest that cells expressing hypo-phosphorylated Mid1 maintain the spindle assembly checkpoint during mitosis but show severe polarity defects. Current research events focus on the cellular localization of Mid1 phosphosite mutants and their ability to directly interact with the cellular membrane.