scholarly journals The GTPase IFT27 is involved in both anterograde and retrograde intraflagellar transport

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Diego Huet ◽  
Thierry Blisnick ◽  
Sylvie Perrot ◽  
Philippe Bastin
Keyword(s):  
Trypanosoma Brucei ◽  
Protein Complexes ◽  
Intraflagellar Transport ◽  
Retrograde Transport ◽  
Small Gtpase ◽  
Anterograde Transport ◽  
Cargo Transport ◽  
Cilia And Flagella ◽  
Bidirectional Movement

The construction of cilia and flagella depends on intraflagellar transport (IFT), the bidirectional movement of two protein complexes (IFT-A and IFT-B) driven by specific kinesin and dynein motors. IFT-B and kinesin are associated to anterograde transport whereas IFT-A and dynein participate to retrograde transport. Surprisingly, the small GTPase IFT27, a member of the IFT-B complex, turns out to be essential for retrograde cargo transport in Trypanosoma brucei. We reveal that this is due to failure to import both the IFT-A complex and the IFT dynein into the flagellar compartment. To get further molecular insight about the role of IFT27, GDP- or GTP-locked versions were expressed in presence or absence of endogenous IFT27. The GDP-locked version is unable to enter the flagellum and to interact with other IFT-B proteins and its sole expression prevents flagellum formation. These findings demonstrate that a GTPase-competent IFT27 is required for association to the IFT complex and that IFT27 plays a role in the cargo loading of the retrograde transport machinery.

scholarly journals Intraflagellar Transport and Functional Analysis of Genes Required for Flagellum Formation in Trypanosomes

2008 ◽  
Vol 19 (3) ◽  
pp. 929-944 ◽  
Author(s):  
Sabrina Absalon ◽  
Thierry Blisnick ◽  
Linda Kohl ◽  
Géraldine Toutirais ◽  
Gwénola Doré ◽  
...  
Keyword(s):  
Trypanosoma Brucei ◽  
Fluorescent Protein ◽  
Protein Complexes ◽  
Intraflagellar Transport ◽  
Retrograde Transport ◽  
Anterograde Transport ◽  
Body Regions ◽  
Cilia And Flagella ◽  
Bidirectional Movement ◽  
Green Fluorescent

Intraflagellar transport (IFT) is the bidirectional movement of protein complexes required for cilia and flagella formation. We investigated IFT by analyzing nine conventional IFT genes and five novel putative IFT genes (PIFT) in Trypanosoma brucei that maintain its existing flagellum while assembling a new flagellum. Immunostaining against IFT172 or expression of tagged IFT20 or green fluorescent protein GFP::IFT52 revealed the presence of IFT proteins along the axoneme and at the basal body and probasal body regions of both old and new flagella. IFT particles were detected by electron microscopy and exhibited a strict localization to axonemal microtubules 3–4 and 7–8, suggesting the existence of specific IFT tracks. Rapid (>3 μm/s) bidirectional intraflagellar movement of GFP::IFT52 was observed in old and new flagella. RNA interference silencing demonstrated that all individual IFT and PIFT genes are essential for new flagellum construction but the old flagellum remained present. Inhibition of IFTB proteins completely blocked axoneme construction. Absence of IFTA proteins (IFT122 and IFT140) led to formation of short flagella filled with IFT172, indicative of defects in retrograde transport. Two PIFT proteins turned out to be required for retrograde transport and three for anterograde transport. Finally, flagellum membrane elongation continues despite the absence of axonemal microtubules in all IFT/PIFT mutant.

scholarly journals The intraflagellar transport dynein complex of trypanosomes is made of a heterodimer of dynein heavy chains and of light and intermediate chains of distinct functions

2014 ◽  
Vol 25 (17) ◽  
pp. 2620-2633 ◽  
Author(s):  
Thierry Blisnick ◽  
Johanna Buisson ◽  
Sabrina Absalon ◽  
Alexandra Marie ◽  
Nadège Cayet ◽  
...  
Keyword(s):  
Protein Complexes ◽  
Intraflagellar Transport ◽  
Retrograde Transport ◽  
High Concentration ◽  
Anterograde Transport ◽  
Heavy Chains ◽  
Cilia And Flagella ◽  
The Stability ◽  
Intermediate Chains ◽  
Dynein Heavy Chains

Cilia and flagella are assembled by intraflagellar transport (IFT) of protein complexes that bring tubulin and other precursors to the incorporation site at their distal tip. Anterograde transport is driven by kinesin, whereas retrograde transport is ensured by a specific dynein. In the protist Trypanosoma brucei, two distinct genes encode fairly different dynein heavy chains (DHCs; ∼40% identity) termed DHC2.1 and DHC2.2, which form a heterodimer and are both essential for retrograde IFT. The stability of each heavy chain relies on the presence of a dynein light intermediate chain (DLI1; also known as XBX-1/D1bLIC). The presence of both heavy chains and of DLI1 at the base of the flagellum depends on the intermediate dynein chain DIC5 (FAP133/WDR34). In the IFT140RNAi mutant, an IFT-A protein essential for retrograde transport, the IFT dynein components are found at high concentration at the flagellar base but fail to penetrate the flagellar compartment. We propose a model by which the IFT dynein particle is assembled in the cytoplasm, reaches the base of the flagellum, and associates with the IFT machinery in a manner dependent on the IFT-A complex.

scholarly journals RUFY3 and RUFY4 are ARL8 effectors that couple lysosomes to dynein-dynactin

2021 ◽  
Author(s):  
Tal Keren-Kaplan ◽  
Amra Saric ◽  
Saikat Ghosh ◽  
Chad Williamson ◽  
Rui Jia ◽  
...  
Keyword(s):  
Hippocampal Neurons ◽  
Retrograde Transport ◽  
Small Gtpase ◽  
Serum Starvation ◽  
Anterograde Transport ◽  
Fyve Domain ◽  
Axon Development ◽  
Necessary And Sufficient

Abstract The small GTPase ARL8 associates with lysosomes and recruits several effectors that mediate coupling to kinesins for anterograde transport, as well as tethering for eventual fusion with other organelles. Herein we report the identification of the “RUN- and FYVE-domain-containing” proteins RUFY3 and RUFY4 as novel ARL8 effectors that couple lysosomes to dynein-dynactin for retrograde transport. Using various biochemical approaches, we find that RUFY3/4 interact with both GTP-bound ARL8 and dynein-dynactin. In addition, we show that RUFY3/4 are both necessary and sufficient for concentration of lysosomes in the juxtanuclear area of the cell. RUFY3/4 also promote retrograde transport of lysosomes in the axon of hippocampal neurons. The function of RUFY3/4 in retrograde transport is required for juxtanuclear redistribution of lysosomes upon serum starvation or cytoplasmic alkalinization, and may underlie the reported roles of RUFY3/4 in axon development/degeneration, cancer and immunity. These studies thus establish RUFY3/4 as novel ARL8-dependent, dynein-dynactin adaptors, and highlight the role of ARL8 in the regulation of both anterograde and retrograde lysosome transport.  

scholarly journals Bidirectional intraflagellar transport is restricted to two sets of microtubule doublets in the trypanosome flagellum

2018 ◽  
Author(s):  
Eloïse Bertiaux ◽  
Adeline Mallet ◽  
Cécile Fort ◽  
Thierry Blisnick ◽  
Serge Bonnefoy ◽  
...  
Keyword(s):  
High Resolution ◽  
Focused Ion Beam ◽  
Protein Complexes ◽  
Ion Beam ◽  
Intraflagellar Transport ◽  
Sem Analysis ◽  
Large Individual ◽  
Resolution Electron ◽  
Cilia And Flagella ◽  
Bidirectional Movement

SummaryIntraflagellar transport (IFT) is the rapid bidirectional movement of large protein complexes driven by kinesin and dynein motors along microtubule doublets of cilia and flagella. Here we used a combination of high-resolution electron and light microscopy to investigate how and where these IFT trains move within the flagellum of the protist Trypanosoma brucei. Focused Ion Beam Scanning Electron Microscopy (FIB-SEM) analysis of trypanosomes showed that trains are found almost exclusively along two sets of doublets (3-4 and 7-8) and distribute in two categories according to their length. High-resolution live imaging of cells expressing mNeonGreen::IFT81 or GFP::IFT52 revealed for the first time IFT trafficking on two parallel lines within the flagellum. Anterograde and retrograde IFT occur on each of these lines. At the distal end, a large individual anterograde IFT train is converted in several smaller retrograde trains in the space of 3-4 seconds while remaining on the same side of the axoneme.

scholarly journals Intraflagellar transport—the “new motility” 20 years later

2012 ◽  
Vol 23 (5) ◽  
pp. 751-753 ◽  
Author(s):  
Keith G. Kozminski
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Protein Complexes ◽  
Intraflagellar Transport ◽  
Cellular Mechanisms ◽  
Intracellular Process ◽  
Cilia And Flagella ◽  
Bidirectional Movement

Intraflagellar transport is the rapid, bidirectional movement of protein complexes along the length of most eukaryotic cilia and flagella. Discovery of this intracellular process in Chlamydomonas reinhardtii 20 years ago led to a rapid discovery of cellular mechanisms that underlie a large number of human ciliopathies. Described herein are the events that led to this discovery.

scholarly journals IFT25 is required for the construction of the trypanosome flagellum

2018 ◽  
Author(s):  
Diego Huet ◽  
Thierry Blisnick ◽  
Sylvie Perrot ◽  
Philippe Bastin
Keyword(s):  
Trypanosoma Brucei ◽  
Transport Process ◽  
Protein Complexes ◽  
Intraflagellar Transport ◽  
Bimolecular Fluorescence Complementation ◽  
Live Cells ◽  
Binding Partner ◽  
Eukaryotic Species ◽  
Cilia And Flagella ◽  
The One

AbstractIntraflagellar transport (IFT), the movement of protein complexes responsible for the assembly of cilia and flagella, is remarkably well conserved from protists to humans. However, two IFT components (IFT25 and IFT27) are missing from multiple unrelated eukaryotic species. In mouse, IFT25 and IFT27 are not required for assembly of several cilia with the noticeable exception of the flagellum of spermatozoa. Here we show that the Trypanosoma brucei IFT25 protein is a proper component of the IFT-B complex and displays typical IFT trafficking. Using bimolecular fluorescence complementation assays, we reveal that IFT25 and IFT27 interact within the flagellum in live cells during the IFT transport process. IFT25-depleted cells construct tiny disorganised flagella that accumulate IFT-B proteins (with the exception of IFT27, the binding partner of IFT25) but not IFT-A proteins. This phenotype is comparable to the one following depletion of IFT27 and shows that IFT25/IFT27 constitute a specific module requested for proper IFT and flagellum construction in trypanosomes. We discuss the possible reasons why IFT25/IFT27 would be required for only some types of cilia.

scholarly journals Electron-tomographic analysis of intraflagellar transport particle trains in situ

2009 ◽  
Vol 187 (1) ◽  
pp. 135-148 ◽  
Author(s):  
Gaia Pigino ◽  
Stefan Geimer ◽  
Salvatore Lanzavecchia ◽  
Eugenio Paccagnini ◽  
Francesca Cantele ◽  
...  
Keyword(s):  
Intraflagellar Transport ◽  
Sensory Function ◽  
Anterograde Transport ◽  
Transmission Electron ◽  
Transport Particle ◽  
Cilia And Flagella ◽  
Bidirectional Movement ◽  
The Individual ◽  
Tomographic Analysis

Intraflagellar transport (IFT) is the bidirectional movement of multipolypeptide particles between the ciliary membrane and the axonemal microtubules, and is required for the assembly, maintenance, and sensory function of cilia and flagella. In this paper, we present the first high-resolution ultrastructural analysis of trains of flagellar IFT particles, using transmission electron microscopy and electron-tomographic analysis of sections from flat-embedded Chlamydomonas reinhardtii cells. Using wild-type and mutant cells with defects in IFT, we identified two different types of IFT trains: long, narrow trains responsible for anterograde transport; and short, compact trains underlying retrograde IFT. Both types of trains have characteristic repeats and patterns that vary as one sections longitudinally through the trains of particles. The individual IFT particles are highly complex, bridged to each other and to the outer doublet microtubules, and are closely apposed to the inner surface of the flagellar membrane.

scholarly journals Bidirectional intraflagellar transport is restricted to two sets of microtubule doublets in the trypanosome flagellum

2018 ◽  
Vol 217 (12) ◽  
pp. 4284-4297 ◽  
Author(s):  
Eloïse Bertiaux ◽  
Adeline Mallet ◽  
Cécile Fort ◽  
Thierry Blisnick ◽  
Serge Bonnefoy ◽  
...  
Keyword(s):  
High Resolution ◽  
Focused Ion Beam ◽  
Protein Complexes ◽  
Ion Beam ◽  
Intraflagellar Transport ◽  
Sem Analysis ◽  
Large Individual ◽  
Resolution Electron ◽  
Cilia And Flagella ◽  
Bidirectional Movement

Intraflagellar transport (IFT) is the rapid bidirectional movement of large protein complexes driven by kinesin and dynein motors along microtubule doublets of cilia and flagella. In this study, we used a combination of high-resolution electron and light microscopy to investigate how and where these IFT trains move within the flagellum of the protist Trypanosoma brucei. Focused ion beam scanning electron microscopy (FIB-SEM) analysis of trypanosomes showed that trains are found almost exclusively along two sets of doublets (3–4 and 7–8) and distribute in two categories according to their length. High-resolution live imaging of cells expressing mNeonGreen::IFT81 or GFP::IFT52 revealed for the first time IFT trafficking on two parallel lines within the flagellum. Anterograde and retrograde IFT occurs on each of these lines. At the distal end, a large individual anterograde IFT train is converted in several smaller retrograde trains in the space of 3–4 s while remaining on the same side of the axoneme.

scholarly journals Retrograde Transport from the Pre-Golgi Intermediate Compartment and the Golgi Complex Is Affected by the Vacuolar H+-ATPase Inhibitor Bafilomycin A1

1998 ◽  
Vol 9 (12) ◽  
pp. 3561-3578 ◽  
Author(s):  
Harri Palokangas ◽  
Ming Ying ◽  
Kalervo Väänänen ◽  
Jaakko Saraste
Keyword(s):  
Brefeldin A ◽  
Retrograde Transport ◽  
Small Gtpase ◽  
Bafilomycin A1 ◽  
Atpase Inhibitor ◽  
Marker Proteins ◽  
Golgi Region ◽  
Intermediate Compartment ◽  
Acidic Compartments

The effect of the vacuolar H+-ATPase inhibitor bafilomycin A1 (Baf A1) on the localization of pre-Golgi intermediate compartment (IC) and Golgi marker proteins was used to study the role of acidification in the function of early secretory compartments. Baf A1 inhibited both brefeldin A- and nocodazole-induced retrograde transport of Golgi proteins to the endoplasmic reticulum (ER), whereas anterograde ER-to-Golgi transport remained largely unaffected. Furthermore, p58/ERGIC-53, which normally cycles between the ER, IC, and cis-Golgi, was arrested in pre-Golgi tubules and vacuoles, and the number of p58-positive ∼80-nm Golgi (coatomer protein I) vesicles was reduced, suggesting that the drug inhibits the retrieval of the protein from post-ER compartments. In parallel, redistribution of β-coatomer protein from the Golgi to peripheral pre-Golgi structures took place. The small GTPase rab1p was detected in short pre-Golgi tubules in control cells and was efficiently recruited to the tubules accumulating in the presence of Baf A1. In contrast, these tubules showed no enrichment of newly synthesized, anterogradely transported proteins, indicating that they participate in retrograde transport. These results suggest that the pre-Golgi structures contain an active H+-ATPase that regulates retrograde transport at the ER–Golgi boundary. Interestingly, although Baf A1 had distinct effects on peripheral pre-Golgi structures, only more central, p58-containing elements accumulated detectable amounts of 3-(2,4-dinitroanilino)-3′-amino-N-methyldipropylamine (DAMP), a marker for acidic compartments, raising the possibility that the lumenal pH of the pre-Golgi structures gradually changes in parallel with their translocation to the Golgi region.

scholarly journals Dynamics of the IFT machinery at the ciliary tip

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Alexander Chien ◽  
Sheng Min Shih ◽  
Raqual Bower ◽  
Douglas Tritschler ◽  
Mary E Porter ◽  
...  
Keyword(s):  
Basal Body ◽  
Full Range ◽  
Intraflagellar Transport ◽  
Feedback Mechanism ◽  
Conventional Imaging ◽  
Range Of Movement ◽  
Anterograde Transport ◽  
Traffic Jam ◽  
Negative Feedback Mechanism ◽  
Cilia And Flagella

Intraflagellar transport (IFT) is essential for the elongation and maintenance of eukaryotic cilia and flagella. Due to the traffic jam of multiple trains at the ciliary tip, how IFT trains are remodeled in these turnaround zones cannot be determined by conventional imaging. Using PhotoGate, we visualized the full range of movement of single IFT trains and motors in Chlamydomonas flagella. Anterograde trains split apart and IFT complexes mix with each other at the tip to assemble retrograde trains. Dynein-1b is carried to the tip by kinesin-II as inactive cargo on anterograde trains. Unlike dynein-1b, kinesin-II detaches from IFT trains at the tip and diffuses in flagella. As the flagellum grows longer, diffusion delays return of kinesin-II to the basal body, depleting kinesin-II available for anterograde transport. Our results suggest that dissociation of kinesin-II from IFT trains serves as a negative feedback mechanism that facilitates flagellar length control in Chlamydomonas.

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