The ChaC family of γ-glutamyl cyclotransferases is required for Leishmania to switch to a slow growth state and for long-term survival of the parasite

• DOI: 10.1016/j.jbc.2022.102510
• Publication Date: 2022-09-17T14:50:10Z
• Authors: Sumit Das; Puja Panja; Gaurab Chowdhury; Saroj Biswas; Yuthika Dholey; Subrata Adak
• Keywords: Epidemiology; Epidemiology and Treatment of Chagas Disease; Quantum mechanics; Global Burden of Leishmaniasis Incidence and Treatment; Term (time); 03 medical and health sciences; Biochemistry, Genetics and Molecular Biology; Health Sciences; Parasite hosting; Animals; Parasites; Molecular Biology; Leishmaniasis; Biology; Leishmania; 0303 health sciences; Physics; Public Health, Environmental and Occupational Health; Life Sciences; Glutathione; Computer science; Nucleotide Metabolism and Enzyme Regulation; 3. Good health; World Wide Web; Medicine; Peptides; Sulfur; Research Article

The ChaC family of γ-glutamyl cyclotransferases is conserved throughout all Kingdoms and catalyzes the degradation GSH. So far, proteins in trypanosomal parasites are missing literature. Here, we report two members (LmChaC2a LmChaC2b) unicellular pathogen Leishmania. Activity measurements suggest that these catalyze GSH but no other peptides. Recombinant LmChaC2a protein shows ∼17-fold lower catalytic efficiency (kcat ∼ 0.9 s-1) than LmChaC2b 15 s-1), although they showed comparable Km values (∼1.75 mM for ∼2.0 toward qRT-PCR Western blot analyses was found to be constitutively expressed, whereas regulated by sulfur stress. To investigate its precise physiological function Leishmania, generated overexpressed, knockout, complement cell lines. Flow cytometric show presence a higher intracellular concentration ROS level, indicative more reductive environment null mutants. We LmChaC2-expressing cells grow GSH-containing sulfur-limited media, while mutants failed grow, suggesting LmChaC2 crucial growth with as only source. Null mutants, reach stationary phase rapidly, display impaired long-term survival, indicating LmChaC2-mediated necessary prolonged survival. In vivo studies LmChaC2-dependent controlled promotes chronic infection parasite. Altogether, data indicate plays an important role homeostasis