Cytokinesis is mediated by an actin-based contractile ring that is attached to the overlying cell membrane. The contractile ring assembles in the cell cortex after anaphase onset at a site midway between the two poles of the mitotic spindle to ensure that the two sets of chromosomes (blue in figure) are equally partitioned into the two daughter cells. Cleavage furrow positioning is achieved through the combined action of astral microtubules (green) and the central spindle (red).
Donglei's paper on the surprising role of the CYK-4 RhoGAP domain in RhoA activation during cytokinesis was just published.
Angika, Yu Chung, and Donglei have published their paper on division plane positioning via membrane associated centralspindlin oligomers.
Ashley Rich has been awarded an NSF predoctoral fellowship!
We use the nematode C. elegans and cultured human cells as model systems and we combine forward and reverse genetics, biochemistry, and live cell imaging to address the following unsolved problems:
How is the cleavage furrow positioned?
How does the contractile ring assemble and function?
How does the central spindle assemble and function?
We have also recently developed a powerful optogenetic toolkit whereby two small and well characterized protein domains interact in a light-dependent manner (see figure). Localization signals or proteins of interest can be fused to each of these two domains to enable light dependent changes in protein localization or protein-protein interactions. We are using this technique to dissect cytokinesis in animal cells.