Identification of CTPS1 Filament Interacting Proteins

CTP synthase (CTPS) catalyzes the formation of CTP in de novo pyrimidine biosynthesis pathway. Compartmentalization of CTPS into filamentous structure is evolutionarily conserved from E.coli, yeast, Drosophila, mice to humans. Recently, we have demonstrated that histidine-mediated protein methylation promotes the formation of CTPS filament under glutamine and/or serum deprivation, which reduces its enzymatic activity and protects it from degradation. However, it is still unclear how the filament assembly takes place. In the current study, we used APEX2-mediated in vivo proximity labeling to identify proteins involved in CTPS filament formation.