Midgut and stomodeal valve attachment of Leishmania in sand flies.

Leishmania development in sand flies involves critical attachment steps to the midgut epithelium and the stomodeal valve, mediated by parasite- and vector-derived molecules. Initial midgut attachment prevents parasite loss during defecation and determines vector competence. In specific vectors like Phlebotomus papatasi, attachment involves galectins and Leishmania lipophosphoglycan, while in permissive species like Lutzomyia longipalpis, mucin adhesion dominates.

Discovery of a novel flagellar filament system underpinning Leishmania adhesion to surfaces.

Adhesion to surfaces is a common strategy employed across biology, especially by pathogens. Within their sand fly vector, Leishmania parasites undergo multiple developmental stages, including the understudied haptomonad form, which adheres to the sand fly stomodeal valve via a highly modified flagellum. This adhesion, likely critical for efficient transmission, is mediated by a complex adhesion plaque from which filaments in the modified flagellum extend toward the cell body and likely connect to the flagellum attachment zone (FAZ), a cytoskeletal structure important for cell morphogenesis.

Distinct modes of interaction within eIF4F-like complexes and susceptibility to the RocA inhibitor for the Trypanosoma brucei EIF4AI translation initiation factor.

Trypanosomatids are parasitic protozoa responsible for major human diseases which are characterized by unique gene expression mechanisms. mRNA translation in these parasites is associated with multiple eIF4F-like complexes, required for mRNA recruitment and ribosome binding. The eukaryotic eIF4F is generally known to require the action of eIF4A, an ATP-dependent RNA helicase, in order to function properly, but not all trypanosomatid eIF4F complexes might require EIF4AI, their single eIF4A homologue.

A comprehensive toolkit for protein localization and functional analysis in trypanosomatids.

African trypanosomes are medically important parasites that cause sleeping sickness in humans and nagana in animals. In addition to their pathogenic role, they have emerged as valuable model organisms for studying fundamental biological processes. Protein tagging is a powerful tool for investigating protein localization and function.

CFAP410 has a bimodular architecture with a conserved surface patch on its N-terminal leucine-rich repeat motif for binding interaction partners.

Cilia and flagella associated protein 410 (CFAP410) is a protein localized at the basal body of cilia/flagella and plays essential roles in ciliogenesis. Multiple single amino acid mutations in CFAP410 have been identified in patients. However, the molecular mechanism for how the mutations cause these disorders remains poorly understood due to a lack of high-resolution structures of the protein.

The C-terminus of CFAP410 forms a tetrameric helical bundle that is essential for its localization to the basal body.

Cilia are antenna-like organelles protruding from the surface of many cell types in the human body. Defects in ciliary structure or function often lead to diseases that are collectively called ciliopathies. Cilia and flagella-associated protein 410 (CFAP410) localizes at the basal body of cilia/flagella and plays essential roles in ciliogenesis, neuronal development and DNA damage repair.

Gels and cells: the Leishmania biofilm as a space and place for parasite transmission.

Leishmania make an abundant glycoprotein and proteophosphoglycan-rich gel, called the promastigote secretory gel, in the anterior midgut of their sand fly vector. This gel is a multi-faceted virulence factor which promotes the survival and transmission of the parasites between hosts. Here, we present the case that Leishmania parasites embedded in the promastigote secretory gel should be redefined as a biofilm as it shares striking similarities in biogenesis, form, and function with biofilms of other unicellular organisms.

Discovery of essential kinetoplastid-insect adhesion proteins and their function in Leishmania-sand fly interactions.

Leishmania species, members of the kinetoplastid parasites, cause leishmaniasis, a neglected tropical disease, in millions of people worldwide. Leishmania has a complex life cycle with multiple developmental forms, as it cycles between a sand fly vector and a mammalian host; understanding their life cycle is critical to understanding disease spread. One of the key life cycle stages is the haptomonad form, which attaches to insect tissues through its flagellum.

Adipose and skin distribution of African trypanosomes in natural animal infections.

Background: Animal African trypanosomiasis, which is caused by different species of African trypanosomes, is a deadly disease in livestock. Although African trypanosomes are often described as blood-borne parasites, there have been recent reappraisals of the ability of these parasites to reside in a wide range of tissues. However, the majority of those studies were conducted on non-natural hosts infected with only one species of trypanosome, and it is unclear whether a similar phenomenon occurs during natural animal infections, where multiple species of these parasites may be present.

Whole cell reconstructions of Leishmania mexicana through the cell cycle.

The unicellular parasite Leishmania has a precisely defined cell architecture that is inherited by each subsequent generation, requiring a highly coordinated pattern of duplication and segregation of organelles and cytoskeletal structures. A framework of nuclear division and morphological changes is known from light microscopy, yet this has limited resolution and the intrinsic organisation of organelles within the cell body and their manner of duplication and inheritance is unknown. Using volume electron microscopy approaches, we have produced three-dimensional reconstructions of different promastigote cell cycle stages to give a spatial and quantitative overview of organelle positioning, division and inheritance.

Leishmania profilin interacts with actin through an unusual structural mechanism to control cytoskeletal dynamics in parasites.

Diseases caused by Leishmania and Trypanosoma parasites are a major health problem in tropical countries. Because of their complex life cycle involving both vertebrate and insect hosts, and >1 billion years of evolutionarily distance, the cell biology of trypanosomatid parasites exhibits pronounced differences to animal cells. For example, the actin cytoskeleton of trypanosomatids is divergent when compared with other eukaryotes.

Disruption of Leishmania flagellum attachment zone architecture causes flagellum loss.

Leishmania are flagellated eukaryotic parasites that cause leishmaniasis and are closely related to the other kinetoplastid parasites such as Trypanosoma brucei. In all these parasites there is a cell membrane invagination at the base of the flagellum called the flagellar pocket, which is tightly associated with and sculpted by cytoskeletal structures including the flagellum attachment zone (FAZ). The FAZ is a complex interconnected structure linking the flagellum to the cell body and has critical roles in cell morphogenesis, function and pathogenicity.

Comprehensive sub-mitochondrial protein map of the parasitic protist Trypanosoma brucei defines critical features of organellar biology.

We have generated a high-confidence mitochondrial proteome (MitoTag) of the Trypanosoma brucei procyclic stage containing 1,239 proteins. For 337 of these, a mitochondrial localization had not been described before. We use the TrypTag dataset as a foundation and take advantage of the properties of the fluorescent protein tag that causes aberrant but fortuitous accumulation of tagged matrix and inner membrane proteins near the kinetoplast (mitochondrial DNA).

Subcellular protein localisation of bloodstream form-upregulated proteins maps stage-specific adaptations.

Genome-wide subcellular protein localisation in through our TrypTag project, has comprehensively dissected the molecular organisation of this important pathogen. Powerful as this resource is has multiple developmental forms and we previously only analysed the procyclic form. This is an insect life cycle stage, leaving the mammalian bloodstream form unanalysed.

Formation and three-dimensional architecture of adhesion in the sand fly vector.

Attachment to a substrate to maintain position in a specific ecological niche is a common strategy across biology, especially for eukaryotic parasites. During development in the sand fly vector, the eukaryotic parasite adheres to the stomodeal valve, as the specialised haptomonad form. Dissection of haptomonad adhesion is a critical step for understanding the complete life cycle of .

Cell-to-flagellum attachment and surface architecture in kinetoplastids.

A key morphological feature of kinetoplastid parasites is the position and length of flagellum attachment to the cell body. This lateral attachment is mediated by the flagellum attachment zone (FAZ), a large complex cytoskeletal structure, which is essential for parasite morphogenesis and pathogenicity. Despite the complexity of the FAZ only two transmembrane proteins, FLA1 and FLA1BP, are known to interact and connect the flagellum to the cell body.

TrypTag.org: from images to discoveries using genome-wide protein localisation in Trypanosoma brucei.

TrypTag was a 4-year project to tag the N- and C-termini of almost all Trypanosoma brucei proteins with a fluorescent protein and record the subcellular localisation through images and manual annotation. We highlight the new routes to cell biological discovery this transformative resource is enabling for parasitologists and cell biologists.

African trypanosome infection patterns in cattle in a farm setting in Southern Ghana.

African Trypanosomiasis is a debilitating disease in both humans and animals that occurs in sub-Saharan Africa and has a severe negative impact on the livelihood of people in the affected areas. The disease is caused by protozoan parasites of the genus Trypanosoma, which is often described simply as blood-borne; however, a number of studies have shown the parasite inhabits many different environments within the host. Control of the disease involves measures that include the use of trypanocidal drugs to which there are growing number of reported cases of resistance.

Diversity in new flagellum tip attachment in bloodstream form African trypanosomes.

The closely related parasites Trypanosoma brucei, T. congolense, and T. vivax cause neglected tropical diseases collectively known as African Trypanosomiasis.

Nucleolar targeting in an early-branching eukaryote suggests a general mechanism for ribosome protein sorting.

The compartmentalised eukaryotic cell demands accurate targeting of proteins to the organelles in which they function, whether membrane-bound (like the nucleus) or non-membrane-bound (like the nucleolus). Nucleolar targeting relies on positively charged localisation signals and has received rejuvenated interest since the widespread recognition of liquid-liquid phase separation (LLPS) as a mechanism contributing to nucleolus formation. Here, we exploit a new genome-wide analysis of protein localisation in the early-branching eukaryote Trypanosoma brucei to analyse general nucleolar protein properties.

Stage-specific transcription activator ESB1 regulates monoallelic antigen expression in Trypanosoma brucei.

Variant surface glycoprotein (VSG) coats bloodstream form Trypanosoma brucei parasites, and monoallelic VSG expression underpins the antigenic variation necessary for pathogenicity. One of thousands of VSG genes is transcribed by RNA polymerase I in a singular nuclear structure called the expression site body (ESB), but how monoallelic VSG transcription is achieved remains unclear. Using a localization screen of 153 proteins we found one, ESB-specific protein 1 (ESB1), that localized only to the ESB and is expressed only in VSG-expressing life cycle stages.

Trypanosomatid Flagellar Pocket from Structure to Function.

The trypanosomatids Trypanosoma brucei, Trypanosoma cruzi, and Leishmania spp. are flagellate eukaryotic parasites that cause serious diseases in humans and animals. These parasites have cell shapes defined by a subpellicular microtubule array and all share a number of important cellular features.

Role for the flagellum attachment zone in Leishmania anterior cell tip morphogenesis.

The shape and form of the flagellated eukaryotic parasite Leishmania is sculpted to its ecological niches and needs to be transmitted to each generation with great fidelity. The shape of the Leishmania cell is defined by the sub-pellicular microtubule array and the positioning of the nucleus, kinetoplast and the flagellum within this array. The flagellum emerges from the anterior end of the cell body through an invagination of the cell body membrane called the flagellar pocket.

Trypanosoma, Paramecium and Tetrahymena: From genomics to flagellar and ciliary structures and cytoskeleton dynamics.

Cilia and flagella play an important role in motility, sensory perception, and the life cycles of eukaryotes, from protists to humans. However, much critical information concerning cilia structure and function remains elusive. The vast majority of ciliary and flagellar proteins analyzed so far are evolutionarily conserved and play a similar role in protozoa and vertebrates.