Revising the Role of Cortical Cytoskeleton during Secretion: Actin and Myosin XI Function in Vesicle Tethering

In plants, secretion of cell wall components and membrane proteins plays a fundamental role in growth and development as well as survival in diverse environments. Exocytosis, as the last step of the secretory trafficking pathway, is a highly ordered and precisely controlled process involving tethering, docking, and fusion of vesicles at the plasma membrane (PM) for cargo delivery. Although the exocytic process and machinery are well characterized in yeast and animal models, the molecular players and specific molecular events that underpin late stages of exocytosis in plant cells remain largely unknown. Here, by using the delivery of functional, fluorescent-tagged cellulose synthase (CESA) complexes (CSCs) to the PM as a model system for secretion, as well as single-particle tracking in living cells, we describe a quantitative approach for measuring the frequency of vesicle tethering events. Genetic and pharmacological inhibition of cytoskeletal function, reveal that the initial vesicle tethering step of exocytosis is dependent on actin and myosin XI. In contrast, treatments with the microtubule inhibitor, oryzalin, did not significantly affect vesicle tethering or fusion during CSC exocytosis but caused a minor increase in transient or aborted tethering events. With data from this new quantitative approach and improved spatiotemporal resolution of single particle events during secretion, we generate a revised model for the role of the cortical cytoskeleton in CSC trafficking.

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Revising the Role of Cortical Cytoskeleton During Secretion: Actin and Myosin XI Function in Vesicle Tethering

10.1101/2021.12.01.470761 ◽

2021 ◽

Author(s):

Weiwei Zhang ◽

Christopher J. Staiger

Keyword(s):

Single Particle ◽

Single Particle Tracking ◽

Quantitative Approach ◽

Spatiotemporal Resolution ◽

Microtubule Inhibitor ◽

Vesicle Tethering ◽

Molecular Events ◽

Myosin Xi ◽

Cortical Cytoskeleton

AbstractIn plants, secretion of cell wall components and membrane proteins plays a fundamental role in growth and development as well as survival in diverse environments. Exocytosis, as the last step of the secretory trafficking pathway, is a highly ordered and precisely controlled process involving tethering, docking, and fusion of vesicles at the plasma membrane (PM) for cargo delivery. Although the exocytic process and machinery are well characterized in yeast and animal models, the molecular players and specific molecular events that underpin late stages of exocytosis in plant cells remain largely unknown. Here, by using the delivery of functional, fluorescent-tagged cellulose synthase (CESA) complexes (CSCs) to the PM as a model system for secretion, as well as single-particle tracking in living cells, we describe a quantitative approach for measuring the frequency of vesicle tethering events. Genetic and pharmacological inhibition of cytoskeletal function, reveal that the initial vesicle tethering step of exocytosis is dependent on actin and myosin XI. In contrast, treatments with the microtubule inhibitor, oryzalin, did not significantly affect vesicle tethering or fusion during CSC exocytosis but caused a minor increase of transient or aborted tethering events. With data from this new quantitative approach and improved spatiotemporal resolution of single particle events during secretion, we generate a revised model for the role of the cortical cytoskeleton in CSC trafficking.

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Arabidopsis Myosin XIK Interacts with the Exocyst Complex to Facilitate Vesicle Tethering during Exocytosis

10.1101/2020.08.18.255984 ◽

2020 ◽

Author(s):

Weiwei Zhang ◽

Lei Huang ◽

Chunhua Zhang ◽

Christopher J. Staiger

Keyword(s):

Mammalian Cells ◽

Secretory Vesicle ◽

Tail Domain ◽

Spatiotemporal Resolution ◽

Dynamic Regulation ◽

Vesicle Tethering ◽

Exocyst Complex ◽

Myosin Xi ◽

Myosin Motors

ABSTRACTMyosin motors are essential players in secretory vesicle trafficking and exocytosis in yeast and mammalian cells; however, similar roles in plants remain a matter for debate, at least for diffusely-growing cells. Here, we demonstrate that Arabidopsis (Arabidopsis thaliana) myosin XIK, via its globular tail domain (GTD), participates in the vesicle tethering step of exocytosis through direct interactions with the exocyst complex. Specifically, myosin XIK GTD bound directly to the SEC5B subunit of exocyst in vitro and functional fluorescently-tagged XIK colocalized with multiple exocyst subunits at plasma membrane (PM)-associated stationary foci. Moreover, genetic and pharmacological inhibition of myosin XI activity reduced the frequency and lifetime of stationary exocyst complexes at the PM. By tracking single exocytosis events of cellulose synthase (CESA) complexes (CSCs) with high spatiotemporal resolution imaging and pair-wise colocalization analysis of myosin XIK, exocyst subunits and CESA6, we demonstrated that XIK associates with secretory vesicles earlier than exocyst and is required for the recruitment of exocyst to the PM tethering site. This study reveals an important functional role for myosin XI in secretion and provides new insights about the dynamic regulation of exocytosis in plants.

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Single particle tracking in systems showing anomalous diffusion: the role of weak ergodicity breaking

Physical Chemistry Chemical Physics ◽

10.1039/c0cp01879a ◽

2011 ◽

Vol 13 (5) ◽

pp. 1800 ◽

Cited By ~ 221

Author(s):

Stas Burov ◽

Jae-Hyung Jeon ◽

Ralf Metzler ◽

Eli Barkai

Keyword(s):

Particle Tracking ◽

Anomalous Diffusion ◽

Single Particle ◽

Single Particle Tracking ◽

Weak Ergodicity ◽

Weak Ergodicity Breaking ◽

Ergodicity Breaking

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Single-Particle Tracking Reveals a Dynamic Role of Actin Filaments in Assisting Long-Range Axonal Transport in Neurons

Bulletin of the Chemical Society of Japan ◽

10.1246/bcsj.20170090 ◽

2017 ◽

Vol 90 (6) ◽

pp. 714-719

Author(s):

Yasuko Osakada ◽

Kai Zhang

Keyword(s):

Axonal Transport ◽

Long Range ◽

Particle Tracking ◽

Single Particle ◽

Actin Filaments ◽

Single Particle Tracking

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Peranan media sosial dalam pengembangan melek politik mahasiswa

Jurnal Civics Media Kajian Kewarganegaraan ◽

10.21831/civics.v14i2.16102 ◽

2017 ◽

Vol 14 (2) ◽

pp. 139-145

Author(s):

Yudha Pradana

Keyword(s):

Social Media ◽

Data Analysis ◽

Likert Scale ◽

Study Habits ◽

Quantitative Approach ◽

Result Show ◽

Political Literacy ◽

Descriptive Method

This research is used quantitative approach and descriptive method. Instrument used by the research is skala Survey of Study Habits and Attitudes questionnaire to describing media social using by students and Likert Scale questionnaire to describing student’s political literacy. Data analysis using Rank Spearman Order.The result show that social media used by students 48% good, 26% fair, and 15% poor. Student’s political literacy are 36% good, 43% fair, and 21% poor. The role of social media in the development of student's political literacy is 54,79% affected by social media, and 45,21% affected by other factors.

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Information-Efficient, Off-Center Sampling Results in Improved Precision in 3D Single-Particle Tracking Microscopy

Entropy ◽

10.3390/e23050498 ◽

2021 ◽

Vol 23 (5) ◽

pp. 498

Author(s):

Chen Zhang ◽

Kevin Welsher

Keyword(s):

Fisher Information ◽

Particle Tracking ◽

Single Particle ◽

Biological Samples ◽

Tracking System ◽

Single Particle Tracking ◽

Uniform Sampling ◽

Single Dimension ◽

3D Localization ◽

Particle Localization

In this work, we present a 3D single-particle tracking system that can apply tailored sampling patterns to selectively extract photons that yield the most information for particle localization. We demonstrate that off-center sampling at locations predicted by Fisher information utilizes photons most efficiently. When performing localization in a single dimension, optimized off-center sampling patterns gave doubled precision compared to uniform sampling. A ~20% increase in precision compared to uniform sampling can be achieved when a similar off-center pattern is used in 3D localization. Here, we systematically investigated the photon efficiency of different emission patterns in a diffraction-limited system and achieved higher precision than uniform sampling. The ability to maximize information from the limited number of photons demonstrated here is critical for particle tracking applications in biological samples, where photons may be limited.

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Role of Single-Particle Energies in Microscopic Interacting Boson Model Double Beta Decay Calculations

Universe ◽

10.3390/universe7030066 ◽

2021 ◽

Vol 7 (3) ◽

pp. 66

Author(s):

Jenni Kotila

Keyword(s):

Beta Decay ◽

Single Particle ◽

Field Potential ◽

Double Beta Decay ◽

Interacting Boson Model ◽

Model Calculations ◽

Single Particle Level ◽

Particle Level ◽

Boson Model

Single-particle level energies form a significant input in nuclear physics calculations where single-particle degrees of freedom are taken into account, including microscopic interacting boson model investigations. The single-particle energies may be treated as input parameters that are fitted to reach an optimal fit to the data. Alternatively, they can be calculated using a mean field potential, or they can be extracted from available experimental data, as is done in the current study. The role of single-particle level energies in the microscopic interacting boson model calculations is discussed with special emphasis on recent double beta decay calculations.

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