Accurate cellular replication balances the biogenesis and turnover of complex structures. In the apicomplexan parasite Toxoplasma gondii, daughter cells form within an intact mother cell, creating additional challenges to ensuring fidelity of division. The cells must distinguish between materials intended to be packaged into daughter buds, and maternal cell material destined for turnover. We have previously shown that depletion of ERK7 interupts this balance, causing the Ubiquitin E3 ligase, CSAR1, to improperly localize from the residual body to the apical complex of daughter buds. This mislocalization of an active E3 ligase causes the improper turnover of daughter cytoskeletal components and results in the loss of the conoid. We hypothesize that the residual body is used to compartmentalize the turnover of cell components during cytokinesis. We aim to determine the mechanisms of regulation of this process, using CSAR1 as an entry point. We are combining multiple cell biological and biochemical methods to identify CSAR1 substrates and regulators, including proximity biotinylation, ubiquitin proteomics, and in vitro reconstitution. This multi-faceted approach will allow us to decipher the components of the ERK7 regulated CSAR1 ubiquitin-proteosome pathway and its role in cytoskeletal turnover.