Cytoplasmic dynein-associated structures move bidirectionallyin vivo

2002 ◽  
Vol 115 (7) ◽  
pp. 1453-1460 ◽  
Author(s):  
Shuo Ma ◽  
Rex L. Chisholm

Intracellular organelle transport is driven by motors that act upon microtubules or microfilaments. The microtubulebased motors, cytoplasmic dynein and kinesin, are believed to be responsible for retrograde and anterograde transport of intracellular cargo along microtubules. Many vesicles display bidirectional movement; however, the mechanism regulating directionality is unresolved. Directional movement might be accomplished by alternative binding of different motility factors to the cargo. Alternatively,different motors could associate with the same cargo and have their motor activity regulated. Although several studies have focused on the behavior of specific types of cargoes, little is known about the traffic of the motors themselves and how it correlates with cargo movement. To address this question, we studied cytoplasmic dynein dynamics in living Dictyostelium cells expressing dynein intermediate chain-green fluorescent protein (IC-GFP) fusion in an IC-null background. Dynein-associated structures display fast linear movement along microtubules in both minus-end and plus-end directions, with velocities similar to that of dynein and kinesin-like motors. In addition, dynein puncta often rapidly reverse their direction. Dynein stably associates with cargo moving in both directions as well as with those that rapidly reverse their direction of movement, suggesting that directional movement is not regulated by altering motor-cargo association but rather by switching activity of motors associated with the cargo. These observations suggest that both plus- and minus-end-directed motors associate with a given cargo and that coordinated regulation of motor activities controls vesicle directionality.

2008 ◽  
Vol 19 (3) ◽  
pp. 929-944 ◽  
Author(s):  
Sabrina Absalon ◽  
Thierry Blisnick ◽  
Linda Kohl ◽  
Géraldine Toutirais ◽  
Gwénola Doré ◽  
...  

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.


2000 ◽  
Vol 113 (18) ◽  
pp. 3151-3159 ◽  
Author(s):  
R. Blum ◽  
D.J. Stephens ◽  
I. Schulz

The mechanism by which soluble proteins without sorting motifs are transported to the cell surface is not clear. Here we show that soluble green fluorescent protein (GFP) targeted to the lumen of the endoplasmic reticulum but lacking any known retrieval, retention or targeting motifs, was accumulated in the lumen of the ERGIC if cells were kept at reduced temperature. Upon activation of anterograde transport by rewarming of cells, lumenal GFP stained a microtubule-dependent, pre-Golgi tubulo-vesicular network that served as transport structure between peripheral ERGIC-elements and the perinuclear Golgi complex. Individual examples of these tubular elements up to 20 microm in length were observed. Time lapse imaging indicated rapid anterograde flow of soluble lumenal GFP through this network. Transport tubules, stained by lumenal GFP, segregated rapidly from COPI-positive membranes after transport activation. A transmembrane cargo marker, the temperature sensitive glycoprotein of the vesicular stomatitis virus, ts-045 G, is also not present in tubules which contained the soluble cargo marker lum-GFP. These results suggest a role for pre-Golgi vesicular tubular membranes in long distance anterograde transport of soluble cargo. http://www.biologists.com/JCS/movies/jcs1334.html


2008 ◽  
Vol 19 (1) ◽  
pp. 274-283 ◽  
Author(s):  
Rosemarie V. Barkus ◽  
Olga Klyachko ◽  
Dai Horiuchi ◽  
Barry J. Dickson ◽  
William M. Saxton

A screen for genes required in Drosophila eye development identified an UNC-104/Kif1 related kinesin-3 microtubule motor. Analysis of mutants suggested that Drosophila Unc-104 has neuronal functions that are distinct from those of the classic anterograde axonal motor, kinesin-1. In particular, unc-104 mutations did not cause the distal paralysis and focal axonal swellings characteristic of kinesin-1 (Khc) mutations. However, like Khc mutations, unc-104 mutations caused motoneuron terminal atrophy. The distributions and transport behaviors of green fluorescent protein-tagged organelles in motor axons indicate that Unc-104 is a major contributor to the anterograde fast transport of neuropeptide-filled vesicles, that it also contributes to anterograde transport of synaptotagmin-bearing vesicles, and that it contributes little or nothing to anterograde transport of mitochondria, which are transported primarily by Khc. Remarkably, unc-104 mutations inhibited retrograde runs by neurosecretory vesicles but not by the other two organelles. This suggests that Unc-104, a member of an anterograde kinesin subfamily, contributes to an organelle-specific dynein-driven retrograde transport mechanism.


2020 ◽  
Author(s):  
Gina A. Monzon ◽  
Lara Scharrel ◽  
Ashwin DSouza ◽  
Ludger Santen ◽  
Stefan Diez

ABSTRACTThe maintenance of intracellular processes like organelle transport and cell division depend on bidirectional movement along microtubules. These processes typically require kinesin and dynein motor proteins which move with opposite directionality. Because both types of motors are often simultaneously bound to the cargo, regulatory mechanisms are required to ensure controlled directional transport. Recently, it has been shown that parameters like mechanical motor activation, ATP concentration and roadblocks on the microtubule surface differentially influence the activity of kinesin and dynein motors in distinct manners. However, how these parameters affect bidirectional transport systems has not been studied. Here, we investigate the regulatory influence of these three parameter using in vitro gliding motility assays and stochastic simulations. We find that the number of active kinesin and dynein motors determines the transport direction and velocity, but that variations in ATP concentration and roadblock density have no significant effect. Thus, factors influencing the force balance between opposite motors appear to be important, whereas the detailed stepping kinetics and bypassing capabilities of the motors have only little effect.


1997 ◽  
Vol 136 (1) ◽  
pp. 71-80 ◽  
Author(s):  
Erik A.C. Wiemer ◽  
Thibaut Wenzel ◽  
Thomas J. Deerinck ◽  
Mark H. Ellisman ◽  
Suresh Subramani

Peroxisomes in living CV1 cells were visualized by targeting the green fluorescent protein (GFP) to this subcellular compartment through the addition of a COOH-terminal peroxisomal targeting signal 1 (GFP–PTS1). The organelle dynamics were examined and analyzed using time-lapse confocal laser scanning microscopy. Two types of movement could be distinguished: a relatively slow, random, vibration-like movement displayed by the majority (∼95%) of the peroxisomes, and a saltatory, fast directional movement displayed by a small subset (∼5%) of the peroxisomes. In the latter instance, peak velocities up to 0.75 μm/s and sustained directional velocities up to 0.45 μm/s over 11.5 μm were recorded. Only the directional type of motion appeared to be energy dependent, whereas the vibrational movement continued even after the cells were depleted of energy. Treatment of cells, transiently expressing GFP–PTS1, with microtubule-destabilizing agents such as nocodazole, vinblastine, and demecolcine clearly altered peroxisome morphology and subcellular distribution and blocked the directional movement. In contrast, the microtubule-stabilizing compound paclitaxel, or the microfilament-destabilizing drugs cytochalasin B or D, did not exert these effects. High resolution confocal analysis of cells expressing GFP–PTS1 and stained with anti-tubulin antibodies revealed that many peroxisomes were associated with microtubules. The GFP–PTS1–labeled peroxisomes were found to distribute themselves in a stochastic, rather than ordered, manner to daughter cells at the time of mitosis.


1999 ◽  
Vol 10 (11) ◽  
pp. 3717-3728 ◽  
Author(s):  
MaryAnn Martin ◽  
Stanley J. Iyadurai ◽  
Andrew Gassman ◽  
Joseph G. Gindhart ◽  
Thomas S. Hays ◽  
...  

In axons, organelles move away from (anterograde) and toward (retrograde) the cell body along microtubules. Previous studies have provided compelling evidence that conventional kinesin is a major motor for anterograde fast axonal transport. It is reasonable to expect that cytoplasmic dynein is a fast retrograde motor, but relatively few tests of dynein function have been reported with neurons of intact organisms. In extruded axoplasm, antibody disruption of kinesin or the dynactin complex (a dynein activator) inhibits both retrograde and anterograde transport. We have tested the functions of the cytoplasmic dynein heavy chain (cDhc64C) and the p150Glued(Glued) component of the dynactin complex with the use of genetic techniques in Drosophila.cDhc64C and Glued mutations disrupt fast organelle transport in both directions. The mutant phenotypes, larval posterior paralysis and axonal swellings filled with retrograde and anterograde cargoes, were similar to those caused by kinesin mutations. Why do specific disruptions of unidirectional motor systems cause bidirectional defects? Direct protein interactions of kinesin with dynein heavy chain and p150Glued were not detected. However, strong dominant genetic interactions between kinesin, dynein, and dynactin complex mutations in axonal transport were observed. The genetic interactions between kinesin and either Glued orcDhc64C mutations were stronger than those betweenGlued and cDhc64C mutations themselves. The shared bidirectional disruption phenotypes and the dominant genetic interactions demonstrate that cytoplasmic dynein, the dynactin complex, and conventional kinesin are interdependent in fast axonal transport.


2000 ◽  
Vol 149 (4) ◽  
pp. 851-862 ◽  
Author(s):  
Andreas Merdes ◽  
Rebecca Heald ◽  
Kumiko Samejima ◽  
William C. Earnshaw ◽  
Don W. Cleveland

NuMA is a large nuclear protein whose relocation to the spindle poles is required for bipolar mitotic spindle assembly. We show here that this process depends on directed NuMA transport toward microtubule minus ends powered by cytoplasmic dynein and its activator dynactin. Upon nuclear envelope breakdown, large cytoplasmic aggregates of green fluorescent protein (GFP)-tagged NuMA stream poleward along spindle fibers in association with the actin-related protein 1 (Arp1) protein of the dynactin complex and cytoplasmic dynein. Immunoprecipitations and gel filtration demonstrate the assembly of a reversible, mitosis-spe-cific complex of NuMA with dynein and dynactin. NuMA transport is required for spindle pole assembly and maintenance, since disruption of the dynactin complex (by increasing the amount of the dynamitin subunit) or dynein function (with an antibody) strongly inhibits NuMA translocation and accumulation and disrupts spindle pole assembly.


2006 ◽  
Vol 17 (4) ◽  
pp. 2021-2034 ◽  
Author(s):  
Vladimir P. Efimov ◽  
Jun Zhang ◽  
Xin Xiang

Proteins in the cytoplasmic dynein pathway accumulate at the microtubule plus end, giving the appearance of comets when observed in live cells. The targeting mechanism for NUDF (LIS1/Pac1) of Aspergillus nidulans, a key component of the dynein pathway, has not been clear. Previous studies have demonstrated physical interactions of NUDF/LIS1/Pac1 with both NUDE/NUDEL/Ndl1 and CLIP-170/Bik1. Here, we have identified the A. nidulans CLIP-170 homologue, CLIPA. The clipA deletion did not cause an obvious nuclear distribution phenotype but affected cytoplasmic microtubules in an unexpected manner. Although more microtubules failed to undergo long-range growth toward the hyphal tip at 32°C, those that reached the hyphal tip were less likely to undergo catastrophe. Thus, in addition to acting as a growth-promoting factor, CLIPA also promotes microtubule dynamics. In the absence of CLIPA, green fluorescent protein-labeled cytoplasmic dynein heavy chain, p150Glued dynactin, and NUDF were all seen as plus-end comets at 32°C. However, under the same conditions, deletion of both clipA and nudE almost completely abolished NUDF comets, although nudE deletion itself did not cause a dramatic change in NUDF localization. Based on these results, we suggest that CLIPA and NUDE both recruit NUDF to the microtubule plus end. The plus-end localization of CLIPA itself seems to be regulated by different mechanisms under different physiological conditions. Although the KipA kinesin (Kip2/Tea2 homologue) did not affect plus-end localization of CLIPA at 32°C, it was required for enhancing plus-end accumulation of CLIPA at an elevated temperature (42°C).


2007 ◽  
Vol 81 (20) ◽  
pp. 11363-11371 ◽  
Author(s):  
M. G. Lyman ◽  
B. Feierbach ◽  
D. Curanovic ◽  
M. Bisher ◽  
L. W. Enquist

ABSTRACT Pseudorabies virus (PRV) mutants lacking the Us9 gene cannot spread from presynaptic to postsynaptic neurons in the rat visual system, although retrograde spread remains unaffected. We sought to recapitulate these findings in vitro using the isolator chamber system developed in our lab for analysis of the transneuronal spread of infection. The wild-type PRV Becker strain spreads efficiently to postsynaptic neurons in vitro, whereas the Us9-null strain does not. As determined by indirect immunofluorescence, the axons of Us9-null infected neurons do not contain the glycoproteins gB and gE, suggesting that their axonal sorting is dependent on Us9. Importantly, we failed to detect viral capsids in the axons of Us9-null infected neurons. We confirmed this observation by using three different techniques: by direct fluorescence of green fluorescent protein-tagged capsids; by transmission electron microscopy; and by live-cell imaging in cultured, sympathetic neurons. This finding has broad impact on two competing models for how virus particles are trafficked inside axons during anterograde transport and redefines a role for Us9 in viral sorting and transport.


2008 ◽  
Vol 181 (6) ◽  
pp. 1027-1039 ◽  
Author(s):  
Junghoon Ha ◽  
Kevin W.-H. Lo ◽  
Kenneth R. Myers ◽  
Tiffany M. Carr ◽  
Michael K. Humsi ◽  
...  

Cytoplasmic dynein is the multisubunit motor protein for retrograde movement of diverse cargoes to microtubule minus ends. Here, we investigate the function of dynein variants, defined by different intermediate chain (IC) isoforms, by expressing fluorescent ICs in neuronal cells. Green fluorescent protein (GFP)–IC incorporates into functional dynein complexes that copurify with membranous organelles. In living PC12 cell neurites, GFP–dynein puncta travel in both the anterograde and retrograde directions. In cultured hippocampal neurons, neurotrophin receptor tyrosine kinase B (TrkB) signaling endosomes are transported by cytoplasmic dynein containing the neuron-specific IC-1B isoform and not by dynein containing the ubiquitous IC-2C isoform. Similarly, organelles containing TrkB isolated from brain by immunoaffinity purification also contain dynein with IC-1 but not IC-2 isoforms. These data demonstrate that the IC isoforms define dynein populations that are selectively recruited to transport distinct cargoes.


Sign in / Sign up

Export Citation Format

Share Document