細胞生物学からのアプローチ

Our cell biological approaches are introduced in this article. First, we show development of a new fixation protocol using trichloroacetic acid (TCA) that is ideal for immunofluorescence microscopy detecting cellular distribution of phosphorylated ERM (ezrin/radixin/moesin) proteins. TCA denatures proteins differently from organic solvents or aldehydes and can be a good alternative to conventional fixatives when immunostaining is not successful. Second, using this new fixation protocol, the small GTPase, Rho was found to be successfully immunostained and this led to understanding of molecular mechanism for determination of the position of the cleavage furrow at cytokinesis through microtubules of the mitotic apparatus. Rho activator is translocated to the presumptive furrow region through microtubules, then, Rho is accumulated and activated there leading to myosin II contractility for furrowing. Third, we show the cell ablation using laser beam during microscopic observation. This enables us to analyze cell responses to the death of neighboring cells in epithelial sheets at early stages.