The unusual flagellar-targeting mechanism and functions of the trypanosome ortholog of the ciliary GTPase Arl13b

Zhang, Yiliu; Huang, Yameng; Srivathsan, Amrita; Lim, Teck Kwang; Lin, Qingsong; He, Cynthia Y.

doi:10.1242/jcs.219071

Cited by 8 publications

(36 citation statements)

References 97 publications

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“…by lacking the proline-rich region or the coiled-coil. Recently, Zhang et al (2018) identified a non-canonical Arl13 gene from Trypanosoma brucei containing the DD_RI_PKA domain (Dimerization/Docking domain of the Regulatory subunit of protein kinase A (PKA)) that is essential for targeting of T. brucei Arl13 to the cilium. Our analysis revealed that the same protein architecture is present also in Euglena gracilis , suggesting it is a synapomorphic character for the whole Euglenozoa phylum (Figure 7B).…”

Section: Resultsmentioning

confidence: 99%

A eukaryote-wide perspective on the diversity and evolution of the ARF GTPase protein family

Vargová

Wideman

Derelle

et al. 2020

Preprint

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ARF family GTPases act in diverse cellular processes, critical for organellar function today and understanding eukaryotic origins. However, our understanding of ARF family evolution is limited. Our phylogenetically comprehensive in silico analyses of ARF family members here doubles the set of ancestral eukaryotic paralogs and challenges existing norms for small GTPases, with examples of non-standard modes of membrane association and novel protein architectures. Evidence for the pan-eukaryotic and ancestral origin of Arf6, Arl13 and Arl16 is presented for the first time, while three newly described ancient sub-families are absent from well-studied model organisms, leaving their functions completely unexplored. Evolutionary analysis of metazoa-specific ARF family GTPases also uncovered several new proteins in animals. Delving back to eukaryogenesis, the relationship within the ARF GTPases sets boundaries for scenarios of vesicle coat origins. Finally, we report the discovery of the archaeal proteins from which the entire eukaryotic ARF family is derived.

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Section: Resultsmentioning

confidence: 99%

A eukaryote-wide perspective on the diversity and evolution of the ARF GTPase protein family

Vargová

Wideman

Derelle

et al. 2020

Preprint

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“…After digestion, the magnetic beads were removed, and the peptide solution was subjected to LC-MS/MS analyses. Proteomics data were analyzed with MASCOT Server 2.4.0 (Matrix Science) and the T. brucei protein database (TbruceiTREU927, release 28) as previously published (71). The identification threshold was set at a 1% false discovery rate, and the estimation of absolute protein amount-the "protein content"-was calculated based on the exponentially modified protein abundance index (emPAI) (72).…”

Section: Methodsmentioning

confidence: 99%

Basal Body Protein TbSAF1 Is Required for Microtubule Quartet Anchorage to the Basal Bodies in Trypanosoma brucei

Dong

Lim

Lin

et al. 2020

mBio

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Sperm flagellar protein 1 (Spef1, also known as CLAMP) is a microtubule-associated protein involved in various microtubule-related functions from ciliary motility to polarized cell movement and planar cell polarity. In Trypanosoma brucei, the causative agent of trypanosomiasis, a single Spef1 ortholog (TbSpef1) is associated with a microtubule quartet (MtQ), which is in close association with several single-copied organelles and is required for their coordinated biogenesis during the cell cycle. Here, we investigated the interaction network of TbSpef1 using BioID, a proximity-dependent protein-protein interaction screening method. Characterization of selected candidates provided a molecular description of TbSpef1-MtQ interactions with nearby cytoskeletal structures. Of particular interest, we identified a new basal body protein TbSAF1, which is required for TbSpef1-MtQ anchorage to the basal bodies. The results demonstrate that MtQ-basal body anchorage is critical for the spatial organization of cytoskeletal organelles, as well as the morphology of the membrane-bound flagellar pocket where endocytosis takes place in this parasite. IMPORTANCE Trypanosoma brucei contains a large array of single-copied organelles and structures. Through extensive interorganelle connections, these structures replicate and divide following a strict temporal and spatial order. A microtubule quartet (MtQ) originates from the basal bodies and extends toward the anterior end of the cell, stringing several cytoskeletal structures together along its path. In this study, we examined the interaction network of TbSpef1, the only protein specifically located to the MtQ. We identified an interaction between TbSpef1 and a basal body protein TbSAF1, which is required for MtQ anchorage to the basal bodies. This study thus provides the first molecular description of MtQ association with the basal bodies, since the discovery of this association ∼30 years ago. The results also reveal a general mechanism of the evolutionarily conserved Spef1/CLAMP, which achieves specific cellular functions via their conserved microtubule functions and their diverse molecular interaction networks.

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“…TbArl13 interacts and catalyses nucleotide exchange on both TbArl3A and TbArl3C, but not TbArl3B. Consistently, only TbArl3A and TbArl3C exhibit flagellar biogenesis effects upon overexpression of the GTP-locked mutants (24).…”

Section: Introductionmentioning

confidence: 72%

“…The flagellum of T. brucei has both signalling and motility functions (23) and is crucial for the viability and pathogenesis of this parasite. Both IFT and LIFT pathway components have been identified in T. brucei (22,24). While the function and regulation of the IFT pathway has been extensively characterized (22), the presence of a conserved LIFT pathway in T. brucei was only recently recognized.…”

Section: Introductionmentioning

confidence: 99%

“…While the function and regulation of the IFT pathway has been extensively characterized (22), the presence of a conserved LIFT pathway in T. brucei was only recently recognized. A single orthologue of Arl13b was found in T. brucei genome, with its protein product enriched in the flagellar axoneme via a Docking and Dimerization domain (24). Interestingly, T. brucei has three Arl3 homologs namely TbArl3A (Tb927.3.3450), TbArl3B (Tb927.10.8580) and TbArl3C (Tb927.6.3650).…”

Section: Introductionmentioning

confidence: 99%

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Flagellar targeting of an arginine kinase requires a conserved lipidated intraflagellar transport (LIFT) pathway inTrypanosoma brucei

Pandey

Huang

Lim

et al. 2020

Preprint

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Both intraflagellar transport (IFT) and lipidated intraflagellar transport (LIFT) pathways are essential for cilia/flagella biogenesis, motility and sensory functions. In the LIFT pathway, lipidated cargoes are transported into the cilia through the coordinated actions of cargo carrier proteins such as Unc119 or PDE6δ, as well as small GTPases Arl13b and Arl3 in the cilium. Our previous studies revealed a single Arl13b ortholog in the evolutionarily divergent Trypanosoma brucei. TbArl13 catalyses two TbArl3 homologs, TbArl3A and TbArl3C, suggesting the presence of a conserved LIFT pathway in these protozoan parasites. Only a single homolog to the cargo carrier protein Unc119 was identified in T.brucei genome, but its function in lipidated protein transport has not been characterized. In this study, we exploited the proximity-based biotinylation approach to identify binding partners of TbUnc119. We showed that TbUnc119 binds to a flagellar arginine kinase TbAK3 in a myristoylation-dependent manner and is responsible for its targeting and enrichment in the flagellum. Interestingly, only TbArl3A, but not TbArl3C interacts with TbUnc119 in a GTP-dependant manner, suggesting functional specialization of Arl3-GTPases in T. brucei. This study establishes the function of TbUnc119 as a myristoylated cargo carrier and supports the presence of a conserved LIFT pathway in T. brucei.

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The unusual flagellar-targeting mechanism and functions of the trypanosome ortholog of the ciliary GTPase Arl13b

Cited by 8 publications

References 97 publications

A eukaryote-wide perspective on the diversity and evolution of the ARF GTPase protein family

A eukaryote-wide perspective on the diversity and evolution of the ARF GTPase protein family

Basal Body Protein TbSAF1 Is Required for Microtubule Quartet Anchorage to the Basal Bodies in Trypanosoma brucei

Flagellar targeting of an arginine kinase requires a conserved lipidated intraflagellar transport (LIFT) pathway inTrypanosoma brucei

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