Dynamin I plays dual roles in the activity-dependent shift in exocytic mode in mouse adrenal chromaffin cells

Fulop, Tiberiu; Doreian, Bryan; Smith, Corey

doi:10.1016/j.abb.2008.04.039

Cited by 46 publications

(58 citation statements)

References 55 publications

(106 reference statements)

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“…The longer t foot in presence of the fully active dynamin might indicate that the foot feature corresponds to the formation of the dynamin assembly and the initiation of GTPase activity, followed by the pore expansion. This concept, supported by several studies (Berberian et al 2009;Burgoyne et al 2001;Fulop et al 2008;Guzman et al 2007;Wang & Richards, 2011) suggests that the mechanochemical activity of dynamin is involved in exocytosis, and that this activity relies on its GTPase properties.…”

Section: Regulation Of Open and Closed Exocytosissupporting

confidence: 50%

The evidence for open and closed exocytosis as the primary release mechanism

Ren

Mellander

Keighron

et al. 2016

Quart. Rev. Biophys.

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Abstract. Exocytosis is the fundamental process by which cells communicate with each other. The events that lead up to the fusion of a vesicle loaded with chemical messenger with the cell membrane were the subject of a Nobel Prize in 2013. However, the processes occurring after the initial formation of a fusion pore are very much still in debate. The release of chemical messenger has traditionally been thought to occur through full distention of the vesicle membrane, hence assuming exocytosis to be all or none. In contrast to the all or none hypothesis, here we discuss the evidence that during exocytosis the vesicle-membrane pore opens to release only a portion of the transmitter content during exocytosis and then close again. This open and closed exocytosis is distinct from kiss-and-run exocytosis, in that it appears to be the main content released during regular exocytosis. The evidence for this partial release via open and closed exocytosis is presented considering primarily the quantitative evidence obtained with amperometry.1. An overview of exocytosis and endocytosis 2 2. Techniques to monitor exocytosis 5 2.1. Patch clamp 6 2.2. Amperometry 6 2.3. Patch amperometry 7 2.4. Cyclic voltammetry 7 2.5. Fluorescence microscopy imaging 83. Traditional models of exocytosis 94. Evidence where partial release during exocytosis appears to be dominant 11 4.1. The total content of a secretory vesicle is greater than the amount released 11 4.2. The majority of exocytotic events are followed by immediate endocytosis 12 4.3. Full distention of the vesicle may not be necessary for quantal release 13 4.4. A flickering fusion pore might regulate quantal release and vesicle recycling 15 4.5. Nanometer-sized pores can be seen as 'feet' associated with amperometric spikes 17 3. Release appears to be only a fraction of vesicle content in mammalian brains 23 7.4. Impact cytometry of adrenal cell vesicles shows a significantly larger catecholamine content then that released 23 7.5. Impact cytometry has been used to measure vesicle content in live cells and this quantity is greater than the amount released 23 7.6. Full distention of the vesicle is not necessary for the measured amperometric current during exocytotic release 23 7.7. Fast changes in cell environment alter the amount of messenger released 23 7.8. Patch amperometry measurements reveal a greater amount of release 23 7.9. Postspike 'feet' are observed with an amperometric spike 23Acknowledgements 24

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Section: Regulation Of Open and Closed Exocytosissupporting

confidence: 50%

The evidence for open and closed exocytosis as the primary release mechanism

Ren

Mellander

Keighron

et al. 2016

Quart. Rev. Biophys.

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“…However, seemingly contradictory results have been reported for the effect of disrupting of the dynamin-amphiphysin association. Graham et al (2002) and Chen et al (2005) have shown an increase in the quantal size of the exocytotic events, while Fulop et al (2008) have claimed a decrease. Elhamdani et al (2006) found no effect.…”

Section: How Does the Synaptophysin-dynamin Association Influence Thementioning

confidence: 99%

The Association of Dynamin with Synaptophysin Regulates Quantal Size and Duration of Exocytotic Events in Chromaffin Cells

González‐Jamett¹,

Báez‐Matus²,

Hevia³

et al. 2010

J. Neurosci.

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Although synaptophysin is one of the most abundant integral proteins of synaptic vesicle membranes, its contribution to neurotransmitter release remains unclear. One possibility is that through its association with dynamin it controls the fine tuning of transmitter release. To test this hypothesis, we took advantage of amperometric measurements of quantal catecholamine release from chromaffin cells. First, we showed that synaptophysin and dynamin interact in chromaffin granule-rich fractions and that this interaction relies on the C terminal of synaptophysin. Experimental maneuvers that are predicted to disrupt the association between these two proteins, such as injection of antibodies against dynamin or synaptophysin, or peptides homologous to the C terminal of synaptophysin, increased the quantal size and duration of amperometric spikes. In contrast, the amperometric current that precedes the spike remained unchanged, indicating that synaptophysin/dynamin association does not regulate the initial fusion pore, but it appears to target a later step of exocytosis to control the amount of catecholamines released during a single vesicle fusion event.

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“…One possibility is that amphiphysin, an important dynamin-binding partner at the synapse, recruits dynamin to the exocytotic sites. However, contradictory results have been reported for the effects of disrupting dynamin/amphiphysin association: Graham et al (2002) and Chen et al (2005) have shown an increase in the quantal size of the exocytotic events, while Fulop et al (2008) have observed a decrease. On the other hand, Elhamdani et al (2006b) found no effect.…”

Section: Transient Fusion Of Secretory Vesiclesmentioning

confidence: 89%

Rapid Endocytosis and Vesicle Recycling in Neuroendocrine Cells

Cárdenas

Marengo

2010

Cell Mol Neurobiol

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Endocytosis is a crucial process for neuroendocrine cells that ensures membrane homeostasis, vesicle recycling, and hormone release reliability. Different endocytic mechanisms have been described in chromaffin cells, such as clathrin-dependent slow endocytosis and clathrin-independent rapid endocytosis. Rapid endocytosis, classically measured in terms of a fast decrease in membrane capacitance, exhibits two different forms, "rapid compensatory endocytosis" and "excess retrieval." While excess retrieval seems to be associated with formation of long-lasting endosomes, rapid compensatory endocytosis is well correlated with exocytotic activity, and it is regarded as a mechanism associated to rapid vesicle recycling during normal secretory activity. It has been suggested that rapid compensatory endocytosis may be related to the prevalence of a transient fusion mode of exo-endocytosis. In the latter mode, the fusion pore, a nanometric-sized channel formed at the onset of exocytosis, remains open for a few hundred milliseconds and later abruptly closes, releasing a small amount of transmitters. By this mechanism, endocrine cell selectively releases low molecular weight transmitters, and rapidly recycles the secretory vesicles. In this article, we discuss the cellular and molecular mechanisms that define the different forms of exocytosis and endocytosis and their impact on vesicle recycling pathways.

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Dynamin I plays dual roles in the activity-dependent shift in exocytic mode in mouse adrenal chromaffin cells

Cited by 46 publications

References 55 publications

The evidence for open and closed exocytosis as the primary release mechanism

The evidence for open and closed exocytosis as the primary release mechanism

The Association of Dynamin with Synaptophysin Regulates Quantal Size and Duration of Exocytotic Events in Chromaffin Cells

Rapid Endocytosis and Vesicle Recycling in Neuroendocrine Cells

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