Protein S-nitrosylation in Plasmodium falciparum

Area of Science:

• Parasitology
• Biochemistry
• Molecular Biology

Background:

• Plasmodium falciparum, the human malaria parasite, faces oxidative and nitrosative stress.
• Nitric oxide (NO) and its derivatives play roles in signaling and stress, but their targets in P. falciparum are poorly understood.
• Protein S-nitrosylation (SNO) is a key NO mechanism, yet its study in malaria parasites is limited.

Purpose of the Study:

• To systematically investigate protein S-nitrosylation in P. falciparum.
• To identify targets of SNO and understand their cellular distribution and function.
• To explore the parasite's mechanisms for dealing with nitrosative stress.

Main Methods:

• Utilized a biotin-switch assay coupled with mass spectrometry.
• Analyzed P. falciparum cell extracts to identify S-nitrosylated proteins.
• Performed mechanistic studies on key identified proteins, including PfTrx1.

Main Results:

• Identified 319 potential SNO targets across various cellular pathways.
• Discovered that glycolysis is a major target, with glyceraldehyde-3-phosphate dehydrogenase inhibited by SNO.
• Showed that P. falciparum thioredoxin 1 (PfTrx1) can be S-nitrosylated and possesses denitrosylating/transnitrosylating activities.

Conclusions:

• S-nitrosylation influences diverse metabolic processes in P. falciparum.
• The thioredoxin system appears crucial for managing nitrosative stress in the parasite.
• Findings enhance understanding of NO signaling and cytotoxicity in malaria parasites.