Logo Logo
Switch language to English
Pohl, Christian (2008): Coordination of late stages of cytokinesis by the inhibitor of apoptosis protein BRUCE. Dissertation, LMU München: Fakultät für Biologie



Cytokinesis involves the formation of a cleavage furrow, followed by abscission, the cutting of the midbody channel, the final bridge between dividing cells. Recently, the midbody ring became known as central for abscission, but its regulation remains enigmatic. This study identifies BRUCE, a 528 kDa multi-functional protein, which processes ubiquitin-conjugating activity, as a major regulator of abscission. During cytokinesis, BRUCE moves from the vesicular system to the midbody ring and serves as a platform for the membrane delivery machinery and mitotic regulators. Depletion of BRUCE in cell cultures causes defective abscission and cytokinesis-associated apoptosis, accompanied by a block of vesicular targeting and defective formation of the midbody and the midbody ring. Notably, ubiquitin relocalizes from midbody microtubules to the midbody ring during cytokinesis, and depletion of BRUCE disrupts this process. Therefore, BRUCE coordinates multiple steps required for abscission, and ubiquitylation might represent the crucial trigger.