Flagellar pocket restructuring through the Leishmania life cycle involves a discrete flagellum attachment zone

Area of Science:

• Cell Biology
• Parasitology
• Evolutionary Biology

Background:

• Leishmania parasites possess a flagellum originating from the flagellar pocket.
• Related Trypanosoma species utilize flagellum attachment zone (FAZ) proteins for flagellar attachment.
• FAZ proteins are essential for flagellar-cell body attachment in Trypanosoma.

Purpose of the Study:

• To investigate the presence and organization of FAZ structures in Leishmania parasites.
• To determine if Leishmania possesses a functional FAZ.
• To understand the role of FAZ in Leishmania morphogenesis and evolution.

Main Methods:

• Utilized Leishmania mexicana cell lines expressing eYFP-fused FAZ protein homologs.
• Employed electron tomography for high-resolution 3D structural analysis of the flagellar pocket and FAZ.
• Expressed Trypanosoma brucei FAZ proteins in Leishmania mexicana to assess assembly.

Main Results:

• Demonstrated the presence of a FAZ structure within the Leishmania flagellar pocket.
• Revealed a precisely organized 3D structure of the flagellar pocket and FAZ, similar to Trypanosoma brucei.
• Showed that Trypanosoma brucei FAZ proteins can assemble into the Leishmania FAZ structure.
• Observed major structural reorganization of the FAZ during the promastigote to amastigote transition.

Conclusions:

• Leishmania parasites possess a previously unrecognized FAZ structure.
• The Leishmania FAZ is intimately associated with flagellar pocket morphogenesis.
• Findings have implications for understanding parasite shape changes and evolution.