TRPV channel OCR-2 is distributed along C. elegans chemosensory cilia by diffusion in a local interplay with intraflagellar transport

Single Molecule Tracking ◽

C Elegans ◽

Normal Diffusion ◽

Cellular Signal ◽

Underlying Mechanisms ◽

AbstractSensing and reacting to the environment is essential for survival and procreation of most organisms. Caenorhabditis elegans senses soluble chemicals with transmembrane proteins (TPs) in the cilia of its chemosensory neurons. Development, maintenance and function of these cilia relies on intraflagellar transport (IFT), in which motor proteins transport cargo, including sensory TPs, back and forth along the ciliary axoneme. Here we use live fluorescence imaging to show that IFT machinery and the sensory TP OCR-2 reversibly redistribute along the cilium after exposure to repellant chemicals. To elucidate the underlying mechanisms, we performed single-molecule tracking experiments and found that OCR-2 distribution depends on an intricate interplay between IFT-driven transport, normal diffusion and subdiffusion that depends on the specific location in the cilium. These insights in the role of IFT on the dynamics of cellular signal transduction contribute to a deeper understanding of the regulation of sensory TPs and chemosensing.

Kinesin-2 from C. reinhardtii is an atypically fast and auto-inhibited motor that is activated by heterotrimerization for intraflagellar transport

10.1101/855940 ◽

2019 ◽

Cited By ~ 1

Author(s):

Punam Sonar ◽

Wiphu Youyen ◽

Augustine Cleetus ◽

Pattipong Wisanpitayakorn ◽

Iman S. Mousavi ◽

...

Keyword(s):

Single Molecule ◽

Motor Coordination ◽

Kinetic Properties ◽

C Elegans ◽

Slow Velocity ◽

Single Molecule Studies ◽

Fast Transport ◽

SummaryThe construction and function of virtually all cilia require the universally conserved process of Intraflagellar Transport (IFT) [1, 2]. During the atypically fast IFT in the green alga C. reinhardtii, up to ten kinesin-2 motors ‘line up’ in a tight assembly on the trains [3], provoking the question of how these motors coordinate their action to ensure smooth and fast transport along the flagellum without standing in each other’s way. Here, we show that the heterodimeric FLA8/10 kinesin-2 alone is responsible for the atypically fast IFT in C. reinhardtii. Notably, in single-molecule studies, FLA8/10 moved at speeds matching those of in vivo IFT [4], but additionally displayed a slow velocity distribution, indicative of auto-inhibition. Addition of the KAP subunit to generate the heterotrimeric FLA8/10/KAP relieved this inhibition, thus providing a mechanistic rationale for heterotrimerization with the KAP subunit in fully activating FLA8/10 for IFT in vivo. Finally, we link fast FLA8/10 and slow KLP11/20 kinesin-2 from C. reinhardtii and C. elegans through a DNA tether to understand the molecular underpinnings of motor coordination during IFT in vivo. For motor pairs from both species, the co-transport velocities very nearly matched the single-molecule velocities, and the complexes both spent roughly 80% of the time with only one of the two motors attached to the microtubule. Thus, irrespective of phylogeny and kinetic properties, kinesin-2 motors prefer to work alone without sacrificing efficiency. Our findings thus offer a simple mechanism for how efficient IFT is achieved across diverse organisms despite being carried out by motors with different properties.

Single-Molecule Tracking Reveals Complex Motility of Transmembrane Proteins in the Chemosensory Cilia of C. elegans

Biophysical Journal ◽

10.1016/j.bpj.2019.11.3113 ◽

2020 ◽

Vol 118 (3) ◽

pp. 572a-573a

Author(s):

Jaap van Krugten ◽

Noemie B. Danne ◽

Erwin J. Peterman

Keyword(s):

Single Molecule ◽

Transmembrane Proteins ◽

Single Molecule Tracking ◽

C Elegans

Caenorhabditis elegans DYF-2, an Orthologue of Human WDR19, Is a Component of the Intraflagellar Transport Machinery in Sensory Cilia

Molecular Biology of the Cell ◽

10.1091/mbc.e06-04-0260 ◽

2006 ◽

Vol 17 (11) ◽

pp. 4801-4811 ◽

Cited By ~ 46

Author(s):

Evgeni Efimenko ◽

Oliver E. Blacque ◽

Guangshuo Ou ◽

Courtney J. Haycraft ◽

Bradley K. Yoder ◽

...

Keyword(s):

Caenorhabditis Elegans ◽

Aspartic Acid ◽

Critical Role ◽

Bardet Biedl Syndrome ◽

Evolutionarily Conserved ◽

Sensory Cilia ◽

Mutant Phenotypes ◽

The intraflagellar transport (IFT) machinery required to build functional cilia consists of a multisubunit complex whose molecular composition, organization, and function are poorly understood. Here, we describe a novel tryptophan-aspartic acid (WD) repeat (WDR) containing IFT protein from Caenorhabditis elegans, DYF-2, that plays a critical role in maintaining the structural and functional integrity of the IFT machinery. We determined the identity of the dyf-2 gene by transgenic rescue of mutant phenotypes and by sequencing of mutant alleles. Loss of DYF-2 function selectively affects the assembly and motility of different IFT components and leads to defects in cilia structure and chemosensation in the nematode. Based on these observations, and the analysis of DYF-2 movement in a Bardet–Biedl syndrome mutant with partially disrupted IFT particles, we conclude that DYF-2 can associate with IFT particle complex B. At the same time, mutations in dyf-2 can interfere with the function of complex A components, suggesting an important role of this protein in the assembly of the IFT particle as a whole. Importantly, the mouse orthologue of DYF-2, WDR19, also localizes to cilia, pointing to an important evolutionarily conserved role for this WDR protein in cilia development and function.

Quantitative cell biology: the essential role of theory

Molecular Biology of the Cell ◽

10.1091/mbc.e14-02-0715 ◽

2014 ◽

Vol 25 (22) ◽

pp. 3438-3440 ◽

Cited By ~ 16

Author(s):

Jonathon Howard

Keyword(s):

Single Molecule ◽

Cell Biology ◽

Scientific Method ◽

Graduate Programs ◽

Rapid Development ◽

Quantitative Biology ◽

The Past ◽

Underlying Mechanisms ◽

Recent Establishment

Quantitative biology is a hot area, as evidenced by the recent establishment of institutes, graduate programs, and conferences with that name. But what is quantitative biology? What should it be? And how can it contribute to solving the big questions in biology? The past decade has seen very rapid development of quantitative experimental techniques, especially at the single-molecule and single-cell levels. In this essay, I argue that quantitative biology is much more than just the quantitation of these experimental results. Instead, it should be the application of the scientific method by which measurement is directed toward testing theories. In this view, quantitative biology is the recognition that theory and models play critical roles in biology, as they do in physics and engineering. By tying together experiment and theory, quantitative biology promises a deeper understanding of underlying mechanisms, when the theory works, or to new discoveries, when it does not.

Propensity of undulatory swimmers, such as worms, to go against the flow

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1424962112 ◽

2015 ◽

Vol 112 (12) ◽

pp. 3606-3611 ◽

Cited By ~ 7

Author(s):

Jinzhou Yuan ◽

David M. Raizen ◽

Haim H. Bau

Keyword(s):

Control Strategies ◽

Aquatic Organisms ◽

Life Cycles ◽

Environmental Cues ◽

Mechanical Forces ◽

C Elegans ◽

The Subject ◽

And Function ◽

First Time

The ability to orient oneself in response to environmental cues is crucial to the survival and function of diverse organisms. One such orientation behavior is the alignment of aquatic organisms with (negative rheotaxis) or against (positive rheotaxis) fluid current. The questions of whether low-Reynolds-number, undulatory swimmers, such as worms, rheotax and whether rheotaxis is a deliberate or an involuntary response to mechanical forces have been the subject of conflicting reports. To address these questions, we use Caenorhabditis elegans as a model undulatory swimmer and examine, in experiment and theory, the orientation of C. elegans in the presence of flow. We find that when close to a stationary surface the animal aligns itself against the direction of the flow. We elucidate for the first time to our knowledge the mechanisms of rheotaxis in worms and show that rheotaxis can be explained solely by mechanical forces and does not require sensory input or deliberate action. The interaction between the flow field induced by the swimmer and a nearby surface causes the swimmer to tilt toward the surface and the velocity gradient associated with the flow rotates the animal to face upstream. Fluid mechanical computer simulations faithfully mimic the behavior observed in experiments, supporting the notion that rheotaxis behavior can be fully explained by hydrodynamics. Our study highlights the important role of hydrodynamics in the behavior of small undulating swimmers and may assist in developing control strategies to affect the animals’ life cycles.

The role of retrograde intraflagellar transport in flagellar assembly, maintenance, and function

The Journal of Cell Biology ◽

10.1083/jcb.201206068 ◽

2012 ◽

Vol 199 (1) ◽

pp. 151-167 ◽

Cited By ~ 70

Author(s):

Benjamin D. Engel ◽

Hiroaki Ishikawa ◽

Kimberly A. Wemmer ◽

Stefan Geimer ◽

Ken-ichi Wakabayashi ◽

...

Keyword(s):

Retrograde Transport ◽

Full Length ◽

Temperature Sensitive ◽

Nonpermissive Temperature ◽

Flagellar Beat ◽

Flagellar Assembly ◽

Ph Shock ◽

The maintenance of flagellar length is believed to require both anterograde and retrograde intraflagellar transport (IFT). However, it is difficult to uncouple the functions of retrograde transport from anterograde, as null mutants in dynein heavy chain 1b (DHC1b) have stumpy flagella, demonstrating solely that retrograde IFT is required for flagellar assembly. We isolated a Chlamydomonas reinhardtii mutant (dhc1b-3) with a temperature-sensitive defect in DHC1b, enabling inducible inhibition of retrograde IFT in full-length flagella. Although dhc1b-3 flagella at the nonpermissive temperature (34°C) showed a dramatic reduction of retrograde IFT, they remained nearly full-length for many hours. However, dhc1b-3 cells at 34°C had strong defects in flagellar assembly after cell division or pH shock. Furthermore, dhc1b-3 cells displayed altered phototaxis and flagellar beat. Thus, robust retrograde IFT is required for flagellar assembly and function but is dispensable for the maintenance of flagellar length. Proteomic analysis of dhc1b-3 flagella revealed distinct classes of proteins that change in abundance when retrograde IFT is inhibited.

Disruption of genes associated with Charcot-Marie-Tooth type 2 lead to common behavioural, cellular and molecular defects inCaenorhabditis elegans

10.1101/605584 ◽

2019 ◽

Author(s):

Ming S. Soh ◽

Xinran Cheng ◽

Jie Liu ◽

Brent Neumann

Keyword(s):

Sensory Neuropathy ◽

Current Frequency ◽

Charcot Marie Tooth ◽

C Elegans ◽

Muscle Structure ◽

Electrophysiological Recordings ◽

Morphological Defects ◽

Underlying Mechanisms ◽

And Function ◽

Peripheral Motor

AbstractCharcot-Marie-Tooth (CMT) disease is an inherited peripheral motor and sensory neuropathy. The disease is divided into demyelinating (CMT1) and axonal (CMT2) neuropathies, and although we have gained molecular information into the details of CMT1 pathology, much less is known about CMT2. Due to its clinical and genetic heterogeneity, coupled with a lack of animal models, common underlying mechanisms remain elusive. In order to understand the biological importance of CMT2-casuative genes, we have studied the behavioural, cellular and molecular consequences of mutating nine different genes associated with CMT2 in the nematodeCaenorhabditis elegans(lin-41/TRIM2, dyn-1/DMN2, unc-116/KIF5A, fzo-1/MFN2, osm-9/TRPV4, cua-1/ATP7A, hsp-25/HSPB1, hint-1/HINT1, nep-2/MME). We show thatC. elegansdefective for these genes display debilitated movement in crawling and swimming assays. Severe morphological defects in cholinergic motors neurons are also evident in two of the mutants (dyn-1andunc-116). Furthermore, we establish novel methods for quantifying muscle morphology and use these to demonstrate striking loss of muscle structure across the mutants that correspond with reductions in muscle function. Finally, using electrophysiological recordings of neuromuscular junction (NMJ) activity, we uncover reductions in spontaneous postsynaptic current frequency inlin-41, dyn-1, unc-116andfzo-1mutants. By comparing the consequences of mutating numerous CMT2-related genes, this study reveals common deficits in muscle structure and function, as well as NMJ signalling when these genes are disrupted.

Aquaporins in regulation of plant protective responses to drought

Ukrainian Botanical Journal ◽

10.15407/ukrbotj78.03.221 ◽

2021 ◽

Vol 78 (3) ◽

pp. 221-234

Author(s):

I.I. Ovrutska ◽

Keyword(s):

Transmembrane Proteins ◽

Main Function ◽

Adverse Conditions ◽

Resistant Varieties ◽

Regulation Of Metabolism ◽

History Of ◽

And Function ◽

Selection Of ◽

Integral Indicator

Plasmolemma permeability is an integral indicator of the functional state of plant cells under stress. Aquaporins (AQPs), specialized transmembrane proteins that form water channels and play an important role in the adaptation of plants to adverse conditions and, in particular, to lack or excess of water, are involved in the formation of the response to drought. The main function of AQPs is to facilitate the movement of water across cell membranes and maintain aqueous cell homeostasis. Under stressful conditions, there is both an increase and decrease in the expression of individual aquaporin genes. Analysis of the data revealed differences in the expression of AQPs genes in stable and sensitive plant genotypes. It turned out that aquaporins in different stress-resistant varieties of the same species also respond differently to drought. The review provides brief information on the history of the discovery of aquaporins, the structure and function of these proteins, summarizes the latest information on the role of aquaporins in the regulation of metabolism and the response of plants to stressors, with particular emphasis on aquaporins in drought protection. The discovery and study of AQPs expands the possibilities of using genetic engineering methods for the selection of new plant species, in particular, more resistant to drought and salinization of the soil, as well as to increase their productivity. The use of aquaporins in biotechnology to improve drought resistance of various species has many prospects.

Caenorhabditis elegans nuclear RNAi factor SET-32 deposits the transgenerational histone modification, H3K23me3

eLife ◽

10.7554/elife.54309 ◽

2020 ◽

Vol 9 ◽

Author(s):

Lianna Schwartz-Orbach ◽

Chenzhen Zhang ◽

Simone Sidoli ◽

Richa Amin ◽

Diljeet Kaur ◽

...

Keyword(s):

Chromatin Modification ◽

Epigenetic Inheritance ◽

Rnai Pathway ◽

C Elegans ◽

And Function ◽

Nuclear Rnai ◽

Factor Set

Nuclear RNAi provides a highly tractable system to study RNA-mediated chromatin changes and epigenetic inheritance. Recent studies have indicated that the regulation and function of nuclear RNAi-mediated heterochromatin are highly complex. Our knowledge of histone modifications and the corresponding histonemodifying enzymes involved in the system remains limited. In this study, we show that the heterochromatin mark, H3K23me3, is induced by nuclear RNAi at both exogenous and endogenous targets in C. elegans. In addition, dsRNA-induced H3K23me3 can persist for multiple generations after the dsRNA exposure has stopped. We demonstrate that the histone methyltransferase SET-32, methylates H3K23 in vitro. Both set-32 and the germline nuclear RNAi Argonaute, hrde-1, are required for nuclear RNAi-induced H3K23me3 in vivo. Our data poise H3K23me3 as an additional chromatin modification in the nuclear RNAi pathway and provides the field with a new target for uncovering the role of heterochromatin in transgenerational epigenetic silencing.