Vesicle movements are governed by the size and dynamics of F-actin cytoskeletal structures in bovine chromaffin cells

Giner, Daniel; López, Inmaculada; Villanueva, José; Torres, Vanesa; Viniegra, Salvador; Gutiérrez, Luis M.

doi:10.1016/j.neuroscience.2007.02.039

Cited by 46 publications

(46 citation statements)

References 24 publications

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“…However, clathrin-coated structures clustered around cortical microtubules have been observed in micrographs (Fowke et al, 1999). It is plausible that cortical microtubules act as a trellis for stabilization of the endocytic protein network or as a diffusion barrier similar to the cortical actin network in mammalian cells (Giner et al, 2007).…”

Section: Drp1c and Clc Colocalize Into Foci At Regions Of Active Membmentioning

confidence: 99%

Dynamics of Arabidopsis Dynamin-Related Protein 1C and a Clathrin Light Chain at the Plasma Membrane

2008

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Plant morphogenesis depends on polarized exocytic and endocytic membrane trafficking. Members of the Arabidopsis thaliana dynamin-related protein 1 (DRP1) subfamily are required for polarized cell expansion and cytokinesis. Using a combination of live-cell imaging techniques, we show that a functional DRP1C green fluorescent fusion protein (DRP1C-GFP) was localized at the division plane in dividing cells and to the plasma membrane in expanding interphase cells. In both tip growing root hairs and diffuse-polar expanding epidermal cells, DRP1C-GFP organized into dynamic foci at the cell cortex, which colocalized with a clathrin light chain fluorescent fusion protein (CLC-FFP), suggesting that DRP1C may participate in clathrin-mediated membrane dynamics. DRP1C-GFP and CLC-GFP foci dynamics are dependent on cytoskeleton organization, cytoplasmic streaming, and functional clathrin-mediated endocytic traffic. Our studies provide insight into DRP1 and clathrin dynamics in the plant cell cortex and indicate that the clathrin endocytic machinery in plants has both similarities and striking differences to that in mammalian cells and yeast.

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Section: Drp1c and Clc Colocalize Into Foci At Regions Of Active Membmentioning

confidence: 99%

Dynamics of Arabidopsis Dynamin-Related Protein 1C and a Clathrin Light Chain at the Plasma Membrane

2008

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“…We studied this possibility as this network can be analysed readily by transmitted light imaging (Giner et al, 2005;Giner et al, 2007); when using this technology, the F-actin cytoskeleton appears as an intricate network formed by polygonal cages that present a dynamic behaviour (Giner et al, 2005). We studied the maximal levels of the Fluo-3 signal in relation to this network during cell stimulation ( Fig.…”

Section: Camentioning

confidence: 99%

“…It has been suggested that the possible cause of such heterogeneity is through the Ca 2+ hotspots that are generated in the membrane (Monck et al, 1994) or even through Ca 2+ release from intracellular reservoirs, such as mitochondria (Pozzan and Rizzuto, 2000;Montero et al, 2002) or the endoplasmic reticulum (ER) . One simple explanation for this heterogeneity is the organization of the cytosolic space itself, which is structured as a dense intricate network of dynamic cytoskeletal polygonal cages that can be readily studied in live cells by transmitted-light microscopy (Giner et al, 2005;Giner et al, 2007). Our relatively simple experimental approach enabled us to demonstrate that the F-actin cytoskeleton must be taken into consideration in order to understand the heterogeneity in Fluo-3 signals.…”

Section: Cytoskeletal Organization and The Distribution Of Fluorescenmentioning

confidence: 99%

“…Since these early studies, our comprehension of the cortical cytoskeleton has evolved as techniques have been introduced that allow the dynamic changes in F-actin during exocytosis to be studied. On the basis of the difference in the interference pattern of transmitted light from an F-actin gel and G-actin in the sol (liquid) state, it has been shown that the cortical cytoskeleton is a dense network of polygonal structures that undergoes dynamic transformations during the secretory process (Giner et al, 2005;Giner et al, 2007). Indeed, these structures extend into the interior of the cell, forming a less dense multipolygonal network.…”

Section: Introductionmentioning

confidence: 99%

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The F-actin cortical network is a major factor influencing the organization of the secretory machinery in chromaffin cells

Torregrosa‐Hetland¹,

Villanueva²,

Giner³

et al. 2011

Journal of Cell Science

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SummaryWe have studied how the F-actin cytoskeleton is involved in establishing the heterogeneous intracellular Ca 2+ levels ([Ca 2+ ] i ) and in the organization of the exocytotic machinery in cultured bovine chromaffin cells. Simultaneous confocal visualization of [Ca 2+ ] i and transmitted light studies of the cytoskeleton showed that, following cell stimulation, the maximal signal from the Ca 2+ -sensitive fluorescent dye Fluo-3 was in the empty cytosolic spaces left by cytoskeletal cages. This was mostly due to the accumulation of the dye in spaces devoid of cytoskeletal components, as shown by the use of alternative Ca 2+ -insensitive fluorescent cytosolic markers. In addition to affecting the distribution of such compounds in the cytosol, the cytoskeleton influenced the location of L-and P-Q-type Ca 2+ channel clusters, which were associated with the borders of cytoskeletal cages in resting and stimulated cells. Indeed, syntaxin-1 and synaptotagmin-1, which are components of the secretory machinery, were present in the same location. Furthermore, granule exocytosis took place at these sites, indicating that the organization of the F-actin cytoskeletal cortex shapes the preferential sites for secretion by associating the secretory machinery with preferential sites for Ca 2+ entry. The influence of this cortical organization on the propagation of [Ca 2+ ] i can be modelled, illustrating how it serves to define rapid exocytosis.

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“…Previous studies have shown that the distinct actin cortex normally observed in chromaffin cells is disrupted by cell stimulation (Vitale et al, 1995;Trifaró et al, 2000;Giner et al, 2007). We set out to test whether pharmacological perturbation of the actin cortex could mimic the difference in stimulation intensity by regulating the kinetics of catecholamine secretion.…”

Section: Disrupting the Actin Cortex Increases Amperometric Spike Ampmentioning

confidence: 99%

Myosin II Activation and Actin Reorganization Regulate the Mode of Quantal Exocytosis in Mouse Adrenal Chromaffin Cells

Doreian¹,

Fulop²,

Smith³

2008

J. Neurosci.

108

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Chromaffin cells of the adrenal medulla are innervated by the sympathetic nervous system. Stimulation causes chromaffin cells to fire action potentials, leading to the exocytosis of various classes of transmitters into the circulation. Low-frequency electrical stimulation (action potentials delivered at 0.5 Hz) causes adrenal chromaffin cells to selectively release catecholamines through a kiss-and-run fusion event. Elevated electrical stimulation (action potentials at 15 Hz) evokes fusion pore dilation, full granule collapse, and additional release of the neuropeptide-containing proteinaceous granule core. Here we apply single-cell electrophysiological, electrochemical, and fluorescence measurements to investigate the cellular mechanism for this shift in exocytic behavior. We show that at low-frequency stimulation, a filamentous-actin cell cortex plays a key role in stabilizing the kiss-and-run fusion event. Increased stimulation disrupts the actin cortex, driving full granule collapse. We show that pharmacological perturbation of the actin cortex supersedes stimulus frequency in controlling exocytic mode. Finally, we show that nonmuscle myosin II activation contributes to the cytoskeleton-dependent control of the fusion event. Inhibition of myosin II or myosin light chain kinase under elevated stimulation frequencies inhibits fusion pore dilation and maintains the granule in a kiss-and-run mode of exocytosis. These results demonstrate an essential role for activity-evoked cytoskeletal rearrangement and the action of myosin II in the regulation of catecholamine and neuropeptide exocytosis and represent an essential element of the sympathetic stress response.

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Vesicle movements are governed by the size and dynamics of F-actin cytoskeletal structures in bovine chromaffin cells

Cited by 46 publications

References 24 publications

Dynamics of Arabidopsis Dynamin-Related Protein 1C and a Clathrin Light Chain at the Plasma Membrane

Dynamics of Arabidopsis Dynamin-Related Protein 1C and a Clathrin Light Chain at the Plasma Membrane

The F-actin cortical network is a major factor influencing the organization of the secretory machinery in chromaffin cells

Myosin II Activation and Actin Reorganization Regulate the Mode of Quantal Exocytosis in Mouse Adrenal Chromaffin Cells

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