CTP synthase (CTPS), the rate-limiting enzyme of de novo CTP synthesis, forms the cytoophidium (meaning 'cell snake' in Greek; cytoophidia as plural) in many types of cells. [1] These cell snakes are dynamic, reversible, and consist of correctly folded proteins. Dozens of cytoophidium-forming proteins have been identified in several organisms across prokaryotes and eukaryotes. [2] Cytoophidium assembly is controlled by ligand binding, post-translational modifications, pH value