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

Richard J Wheeler,Jack D Sunter,Keith Gull

doi:10.1242/jcs.183152

Richard J Wheeler, Jack D Sunter + Show 1 more

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https://doi.org/10.1242/jcs.183152

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Abstract

ABSTRACTLeishmania promastigote parasites have a flagellum, which protrudes from the flagellar pocket at the cell anterior, yet, surprisingly, have homologs of many flagellum attachment zone (FAZ) proteins – proteins used in the related Trypanosoma species to laterally attach the flagellum to the cell body from the flagellar pocket to the cell posterior. Here, we use seven Leishmania mexicana cell lines that expressed eYFP fusions of FAZ protein homologs to show that the Leishmania flagellar pocket includes a FAZ structure. Electron tomography revealed a precisely defined 3D organisation for both the flagellar pocket and FAZ, with striking similarities to those of Trypanosoma brucei. Expression of two T. brucei FAZ proteins in L. mexicana showed that T. brucei FAZ proteins can assemble into the Leishmania FAZ structure. Leishmania therefore have a previously unrecognised FAZ structure, which we show undergoes major structural reorganisation in the transition from the promastigote (sandfly vector) to amastigote (in mammalian macrophages). Morphogenesis of the Leishmania flagellar pocket, a structure important for pathogenicity, is therefore intimately associated with a FAZ; a finding with implications for understanding shape changes involving component modules during evolution.

Highlights

Trypanosoma and Leishmania are two related genera that include many major human and livestock pathogens, such as Leishmania mexicana, which causes New World cutaneous leishmaniasis, and Trypanosoma brucei, which causes African sleeping sickness
We chose to localise FAZ1 (LmxM.36.5970), FAZ2 (LmxM.12.1130), FAZ5 (LmxM.36.5970), FAZ8 (LmxM33.2570), ClpGM6 (LmxM.27.0490), FLA1BP (LmxM.10.0620) and FAZ10 (LmxM.22.1320) as these proteins are found along the majority of the length of the flagellum attachment zone (FAZ) in T. brucei
Here, we provide an integrated view of the Leishmania flagellar pocket region in both the promastigote and amastigote using electron tomography analysis and eYFP tagging

Summary

Introduction

Trypanosoma and Leishmania are two related genera that include many major human and livestock pathogens, such as Leishmania mexicana, which causes New World cutaneous leishmaniasis, and Trypanosoma brucei, which causes African sleeping sickness. These cells have a highly defined internal organisation (Lacomble et al, 2009, 2010; Sherwin and Gull, 1989), and undergo precise morphogenesis during division (Ambit et al, 2011; Robinson et al, 1995; Sheriff et al, 2014; Sherwin and Gull, 1989; Wheeler et al, 2011, 2013a) and precise morphogenesis during adaptation of cell shape to different environments (Gadelha et al, 2013; Rotureau et al, 2011, 2012; Sharma et al, 2008; Wheeler et al, 2015) How they generate their shape is of interest because of its apparent co-evolution with different pathogenic life cycles and the. Correct pocket formation is vital for cell morphogenesis, viability and infectivity, as evidenced in T. brucei (Absalon et al, 2008; Bonhivers et al, 2008)

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