Autophagy is a mechanism responsible for intracellular degradation and recycling of macromolecules and organelles, essential for cell survival in adverse conditions. More than 40 autophagy-related (ATG) genes have been identified and characterized in fungi, among them ATG4 and ATG8. ATG4 encodes a cysteine protease (Atg4) that plays an important role in autophagy by initially processing Atg8 at its C-terminus region. Atg8 is a ubiquitin-like protein essential for the synthesis of the double-layer membrane that constitutes the autophagosome vesicle, responsible for delivering the cargo from the cytoplasm to the vacuole lumen. The contributions of Atg-related proteins in the pathogenic yeast in the genus Cryptococcus remain to be explored, to elucidate the molecular basis of the autophagy pathway. In this context, we aimed to investigate the role of autophagy-related proteins 4 and 8 (Atg4 and Atg8) during autophagy induction and their contribution with non-autophagic events in C. neoformans. We found that Atg4 and Atg8 are conserved proteins and that they interact physically with each other. ATG gene deletions resulted in cells sensitive to nitrogen starvation. ATG4 gene disruption affects Atg8 degradation and its translocation to the vacuole lumen, after autophagy induction. Both atg4 and atg8 mutants are more resistant to oxidative stress, have an impaired growth in the presence of the cell wall-perturbing agent Congo Red, and are sensitive to the proteasome inhibitor bortezomib (BTZ). By that, we conclude that in C. neoformans the autophagy-related proteins Atg4 and Atg8 play an important role in the autophagy pathway; which are required for autophagy regulation, maintenance of amino acid levels and cell adaptation to stressful conditions. OPEN ACCESS Citation: Roberto TN, Lima RF, Pascon RC, Idnurm A, Vallim MA (2020) Biological functions of the autophagy-related proteins Atg4 and Atg8 in Cryptococcus neoformans. PLoS ONE 15(4): e0230981. https://doi.org/10.Data Availability Statement: All relevant data are within the manuscript and its Supporting Information files.individuals [2]. The therapy against cryptococcosis requires a long period of treatment with antifungal drugs used singly or in combination, some of which are highly toxic to the patient [3]. Due to the long period of clinical treatment, some reports indicate that fungi of the genus Cryptococcus may have a high potential to antifungal resistance, which could explain the therapeutic failures and recurrent relapses in the patients with cryptococcosis [4]. Thus, further studies for new strategies that contribute with the knowledge about the treatment of this mycosis, leading to the deficiency of growth, multiplication, and/or survival of the fungus in the host are of great importance. In this context, the elucidation of autophagic pathways in fungi may provide new insights into the relationship established during the infection process between pathogen and host [5].Autophagy is an intracellular mechanism responsible for degradation and recycling of macr...