Protein Kinase Inhibitors and Oxidative Stress Modulate In Vivo Phosphorylation of Trypanosoma cruzi DNA Polymerase β

Area of Science:

• Molecular Biology
• Parasitology
• Drug Discovery

Background:

• Protein kinases regulate vital processes in Trypanosoma cruzi, making them key targets for Chagas disease therapeutics.
• Understanding T. cruzi protein phosphorylation is crucial for identifying new drug targets.

Purpose of the Study:

• To investigate the effects of specific protein kinase inhibitors on T. cruzi protein phosphorylation, focusing on DNA polymerase beta (TcPolβ).
• To explore the impact of oxidative stress on protein tyrosine phosphorylation in T. cruzi.
• To identify phosphorylation sites on TcPolβ by specific T. cruzi protein kinases.

Main Methods:

• Utilized p38 MAPK, MEK, and ERK pathway inhibitors to assess in vivo TcPolβ phosphorylation.
• Employed Genistein, a tyrosine kinase inhibitor, to evaluate global and TcPolβ phosphorylation.
• Induced oxidative stress to examine its effect on tyrosine phosphorylation.
• Determined TcPolβ phosphorylation sites in vitro using TcPKC2 and TcWee570 kinases.

Main Results:

• p38 MAPK and MEK inhibitors reduced TcPolβ Ser/Thr phosphorylation by ~50%.
• Genistein inhibited both Ser/Thr and Tyr phosphorylation of various epimastigote proteins.
• Oxidative stress doubled global tyrosine phosphorylation and increased TcPolβ phosphorylation.
• TcPKC2 and TcWee570 phosphorylated TcPolβ at both Ser/Thr and Tyr residues.

Conclusions:

• Small-molecule kinase inhibitors modulate TcPolβ phosphorylation in vivo.
• The dual inhibitory action of Genistein and the dual phosphorylation activity of TcPKC2/TcWee570 suggest potential dual-activity kinases in T. cruzi.
• Further research is needed to confirm the existence and function of dual-activity kinases in T. cruzi for therapeutic targeting.