Multiple Calcium Pathways Induce the Expression of SNAP‐25 Protein in Chromaffin Cells

Garcı́a-Palomero, Esther; Montiel, Carmen; Herrero, Carlos J.; Garcı́a, Antonio G.; Álvarez, Rocío; Arnalich, Francisco; Renart, Jaime; Lara, Hernán E.; Cárdenas, Ana Marı́a

doi:10.1046/j.1471-4159.2000.0741049.x

Cited by 13 publications

(23 citation statements)

References 55 publications

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“…Together with VAMP-2 and the plasma membrane-located syntaxin1, SNAP-25 can engage into a four helix bundle that is thought to force the membranes of vesicle and presynaptic plasma membrane into close apposition for membrane fusion [23][24][25]. Activity-dependent changes in SNAP-25 expression have been reported [26]. Moreover, SNAP-25 becomes phosphorylated at ser 187 by protein kinase C [27] upon depolarization [28], leading to dissociation of SNAP-25 from syntaxin in vitro [27].…”

Section: Discussionmentioning

confidence: 99%

Synaptic vesicle proteins under conditions of rest and activation: Analysis by 2-D difference gel electrophoresis

et al. 2006

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Synaptic vesicles are organelles of the nerve terminal that secrete neurotransmitters by fusion with the presynaptic plasma membrane. Vesicle fusion is tightly controlled by depolarization of the plasma membrane and a set of proteins that may undergo post-translational modifications such as phosphorylation. In order to identify proteins that undergo modifications as a result of synaptic activation, we induced massive exocytosis and analysed the synaptic vesicle compartment by benzyldimethyl-n-hexadecylammonium chloride (BAC)/SDS-PAGE and difference gel electrophoresis (DIGE) followed by MALDI-TOF-MS. We identified eight proteins that revealed significant changes in abundance following nerve terminal depolarization. Of these, six were increased and two were decreased in abundance. Three of these proteins were phosphorylated as detected by Western blot analysis. In addition, we identified an unknown synaptic vesicle protein whose abundance increased on synaptic activation. Our results demonstrate that depolarization of the presynaptic compartment induces changes in the abundance of synaptic vesicle proteins and post-translational protein modification.

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Section: Discussionmentioning

confidence: 99%

Synaptic vesicle proteins under conditions of rest and activation: Analysis by 2-D difference gel electrophoresis

et al. 2006

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“…SNAP-25 is a SNARE protein that is expressed in pancreatic islets and is involved in insulin release [Sadoul et al, 1995;Wheeler et al, 1996]. SNAP-25 mRNA expression was significantly increased when chromaffin cells [Garcia-Palomero et al, 2000;Montiel et al, 2003] and rat granulosa cells [Grosse et al, 2000] were stimulated to release neurotransmitters, and these events were closely related to the influx of calcium ions.…”

Section: Discussionmentioning

confidence: 99%

An extremely low frequency magnetic field attenuates insulin secretion from the insulinoma cell line, RIN‐m

Sakurai

Satake

Sumi

et al. 2004

Bioelectromagnetics

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In this study, we investigated the effects of exposure to an extremely low frequency magnetic field (ELFMF) on hormone secretion from an islet derived insulinoma cell line, RIN-m. We stimulated RIN-m cells to secrete insulin under exposure to an ELFMF, using our established system for the exposure of cultured cells to an ELFMF at 5 mT and 60 Hz, or under sham exposure conditions for 1 h and observed the effects. In the presence of a depolarizing concentration of potassium (45 mM KCl), exposure to ELFMF significantly attenuated insulin release from RIN-m cells, compared to sham exposed cells. Treatment with nifedipine reduced the difference in insulin secretion between cells exposed to an ELFMF and sham exposed cells. The expression of mRNA encoding synaptosomal associated protein of 25 kDa (SNAP-25) and synaptotagmin 1, which play a role in exocytosis in hormone secretion and influx of calcium ions, decreased with exposure to an ELFMF in the presence of 45 mM KCl. These results suggest that exposure to ELFMF attenuates insulin secretion from RIN-m cells by affecting calcium influx through calcium channels.

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“…2006), protein kinase activation (Mendoza et al. 2003), and gene expression (García‐Palomero et al. 2000b).…”

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confidence: 99%

Calcium channel subtypes differentially regulate fusion pore stability and expansion

Ardiles

González‐Jamett

Maripillán

et al. 2007

Journal of Neurochemistry

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Various studies have focused in the relative contribution of different voltage-activated Ca(2+) channels (VACC) to total transmitter release. However, how Ca(2+) entry through a given VACC subtype defines the pattern of individual exocytotic events remains unknown. To address this question, we have used amperometry in bovine chromaffin cells. L, N, and P/Q channels were individually or jointly blocked with furnidipine, omega-conotoxin GVIA, omega-agatoxin IVA, or omega-conotoxin MVIIC. The three channel types contributed similarly to cytosolic Ca(2+) signals induced by 70 mmol/L K(+). However, they exhibited different contributions to the frequency of exocytotic events and they were shown to differently regulate the final steps of the exocytosis. When compared with the other VACC subtypes, Ca(2+) entry through P/Q channels effectively induced exocytosis, it decreased fusion pore stability and accelerated its expansion. Conversely, Ca(2+) entry through N channels was less efficient in inducing exocytotic events, also slowing fusion pore expansion. Finally, Ca(2+) entry through L channels inefficiently induced exocytosis, and the individual blockade of this channel significantly modified fusion pore dynamics. The distance between a given VACC subtype and the release sites could account for the differential effects of the distinct VACC on the fusion pore dynamics.

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Multiple Calcium Pathways Induce the Expression of SNAP‐25 Protein in Chromaffin Cells

Cited by 13 publications

References 55 publications

Synaptic vesicle proteins under conditions of rest and activation: Analysis by 2-D difference gel electrophoresis

Synaptic vesicle proteins under conditions of rest and activation: Analysis by 2-D difference gel electrophoresis

An extremely low frequency magnetic field attenuates insulin secretion from the insulinoma cell line, RIN‐m

Calcium channel subtypes differentially regulate fusion pore stability and expansion

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