Protein phosphorylation by intact Babesia bovis

Area of Science:

• Parasitology
• Molecular Biology
• Biochemistry

Background:

• Babesia bovis is an intraerythrocytic parasite causing significant economic losses in cattle.
• Understanding the molecular mechanisms of Babesia bovis, particularly protein phosphorylation, is crucial for developing control strategies.

Purpose of the Study:

• To investigate the protein phosphorylation patterns in Babesia bovis.
• To characterize the phosphorylation system and identify the origin of phosphorylated proteins.

Main Methods:

• Babesia bovis parasites were labeled with [32P]orthophosphate and [35S]methionine.
• Two-dimensional electrophoresis was used to analyze protein phosphorylation.
• The effect of cyclic nucleotides and calcium ionophore A23187 on phosphorylation was assessed.

Main Results:

• Babesia bovis rapidly incorporated [32P]orthophosphate into over 30 polypeptide chains, predominantly membrane or particle-bound.
• Phosphorylation occurred more rapidly in free parasites compared to parasitized erythrocytes.
• The calcium ionophore A23187 strongly inhibited phosphorylation and protein synthesis, while cAMP and cGMP had minimal effects.
• Phosphorylated polypeptides were synthesized de novo within the parasite, indicating they were of babesial origin.

Conclusions:

• Babesia bovis possesses a robust protein phosphorylation system, likely essential for its survival and virulence.
• The study identified babesial-derived proteins as the primary targets of phosphorylation.
• Calcium signaling may play a critical role in regulating Babesia bovis protein synthesis and phosphorylation.