African trypanosomes contain calmodulin which is distinct from host calmodulin

Area of Science:

• Parasitology
• Molecular Biology
• Biochemistry

Background:

• African trypanosomes undergo complex morphological and biochemical changes during their life cycle.
• Calcium (Ca2+) fluxes are potential regulators of these developmental transitions.

Purpose of the Study:

• To investigate the role of calcium (Ca2+) fluxes in coordinating African trypanosome life cycle changes.
• To identify and characterize the calcium-binding protein calmodulin in Trypanosoma brucei rhodesiense.

Main Methods:

• Identified calmodulin in two developmental stages of Trypanosoma brucei rhodesiense.
• Compared trypanosome calmodulin with host (bovine brain, rat erythrocytes) and Tetrahymena calmodulin using gel electrophoresis, CNBr-cleavage, and functional assays.
• Assessed the effects of calmodulin inhibitors (trifluoperazine, penfluridol) on trypanosome viability.

Main Results:

• Calmodulin was identified in both slender bloodstream trypomastigotes and procyclic forms of Trypanosoma brucei rhodesiense.
• Specific calmodulin content and intracellular distribution changed during the transition from bloodstream to procyclic stages.
• Trypanosome calmodulin exhibited distinct physical and functional properties compared to host calmodulin but shared similarities with Tetrahymena calmodulin.
• Trifluoperazine demonstrated cytotoxicity to trypanosomes in vitro.

Conclusions:

• Calmodulin is a functional component of African trypanosomes.
• Calmodulin likely plays a significant role in mediating the host-parasite relationship in trypanosomiasis.