Parasite Proteases: Survival, nutrition and infection

Proteolytic enzymes, also called proteases, peptidases or proteinases, are enzymes that hydrolyze peptide bonds of peptides and proteins. Proteases are classified into families based on their principal catalytic residue, with aspartic, cysteine, glutamic, metallo-, asparagine, serine, and threonine proteases being the main families. Furthermore, proteolytic enzymes can be classed as either exopeptidases or endopeptidases. Exopeptidases cleave proteins and peptides adjacent to a free amino or carboxyl terminus, while endopeptidases cleave peptide bonds of nonterminal amino acids. Oligopeptidases, in particular, are endopeptidases that cleave only peptides.

Proteases are involved in both physiological and pathological processes. Proteases have several functions such as being involved in nutrition and turnover of proteins; maintenance of homeostasis and regulation of physiological processes; intracellular signaling; regulation of cell death including apoptosis, regulated necrosis, necroptosis, pyroptosis and NETosis; matrix remodeling of cell-cell and cell-matrix adhesion molecules; host immune response modulation including the regulation of bioactive chemokines and cytokines; and the activation and processing of bioactive peptides.

Proteases from parasites participate in the metabolism of host proteins, turnover of protein for nutrition and cell differentiation throughout the life cycle, invasion of host cells, and evasion of the host immune system. Due to their importance, proteases have been studied as potential anti-parasitic therapeutic targets for drug and vaccine development. The development of new drugs based on parasite proteases requires the determination of the protease structure, validation of the target protease, and the discovery of specific parasite protease inhibitors with the capacity to eliminate the parasites. Proteases could also be useful as a diagnostic tool for the confirmation of disease or as a marker for disease progression.

In this topic, the main idea is to understand the participation of proteases in the biological processes within the parasite or in the virulence process to promote their survival in the host. This Research Topic welcomes article types including Original Research, Reviews, and Perspectives from the following areas;

• Protease function in the parasite or in the host cell invasion;
• Biology, biochemistry and evolution of parasite proteases;
• Cellular and subcellular localization;
• Parasite protease network in the intracellular signaling;
• Parasite protease structure and substrate/inhibitor characterization;
• Drug development using protease inhibitors;
• Drug target validation using molecular biology tools;
• Diagnostic tools and biomarkers;
• Vaccines using proteases as antigens;
• Biotechnological applications