Calcium‐dependent acetylcholine release from <i>Xenopus</i> oocytes: simultaneous ionic currents and acetylcholine release recordings

Aleu, Jordi; Blasi, Juan; Solsona, Carles; Marsal, Jordi

doi:10.1046/j.1460-9568.2002.02208.x

Cited by 15 publications

(4 citation statements)

References 38 publications

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“…The distribution of Vangl2 coincided with the staining of an antibody raised against the post-Golgi v-SNARE protein vesicle associated membrane protein 1, VAMP1 (synaptobrevin) (Aleu et al, 2002) (Fig. 3A for VAMP1), and not with markers for endoplasmic reticulum, Golgi, endosome, lysosome or retromer complex (data not shown).…”

Section: Vangl2 Interacts With the Post-golgi Vesicle Protein Vamp1 Imentioning

confidence: 74%

The roles of maternal Vangl2 and aPKC inXenopusoocyte and embryo patterning

et al. 2011

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SUMMARYThe Xenopus oocyte contains components of both the planar cell polarity and apical-basal polarity pathways, but their roles are not known. Here, we examine the distribution, interactions and functions of the maternal planar cell polarity core protein Vangl2 and the apical-basal complex component aPKC. We show that Vangl2 is distributed in animally enriched islands in the subcortical cytoplasm in full-grown oocytes, where it interacts with a post-Golgi v-SNARE protein, VAMP1, and acetylated microtubules. We find that Vangl2 is required for the stability of VAMP1 as well as for the maintenance of the stable microtubule architecture of the oocyte. We show that Vangl2 interacts with atypical PKC, and that both the acetylated microtubule cytoskeleton and the Vangl2-VAMP1 distribution are dependent on the presence of aPKC. We also demonstrate that aPKC and Vangl2 are required for the cell membrane asymmetry that is established during oocyte maturation, and for the asymmetrical distribution of maternal transcripts for the germ layer and dorsal/ventral determinants VegT and Wnt11. This study demonstrates the interaction and interdependence of Vangl2, VAMP1, aPKC and the stable microtubule cytoskeleton in the oocyte, shows that maternal Vangl2 and aPKC are required for specific oocyte asymmetries and vertebrate embryonic patterning, and points to the usefulness of the oocyte as a model to study the polarity problem.

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Section: Vangl2 Interacts With the Post-golgi Vesicle Protein Vamp1 Imentioning

confidence: 74%

The roles of maternal Vangl2 and aPKC inXenopusoocyte and embryo patterning

et al. 2011

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“…The increase in capacitance observed in DDW-injected oocytes could be mediated by the endogenous proteins. 32 However, in spite of the increase in inward current current-voltage relationship, Syt1 had no significant effect on the kinetics parameters at all voltages; data was collected from groups of 10-12 oocytes (Fig. S2B).…”

Section: Modulation Of Ca V 21 By Sx1a the Functional Consequencesmentioning

confidence: 95%

Ca_V2.1 (P/Q channel) interaction with synaptic proteins is essential for depolarization-evoked release

Cohen-Kutner

Nachmanni²,

Atlas³

2010

Channels

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It is well-established that syntaxin 1A (Sx1A), SNAP-25 and synaptotagmin (Syt1) either alone or in combination, modify the kinetic properties of voltage-gated Ca(2+) channels (VGCCs). The interaction interface resides mainly at the cytosolic II-III domain of the alpha1 subunit of the channels, while Sx1A interacts with the channel also via two highly conserved cysteine residues at the transmembrane domain. In the present study, we characterized Ca(2+)-independent coupling of the human neuronal P/Q-type calcium channel (Ca(V)2.1) with Sx1A, SNAP-25, Syt1 and synaptobrevin (VAMP) in BAPTA-injected Xenopus oocytes. The co-expression of Ca(V)2.1 with Sx1A, SNAP-25 and Syt1, produced a multiprotein complex with distinctive kinetic properties analogous to the excitosome complexes generated by Ca(V)1.2, Ca(V)2.2 and Ca(V)2.3. The distinct kinetic properties of Ca(V)2.1 acquired by close association with Syt1 and t-SNAREs, suggests that the vesicle is tethered to the neuronal channel and to the exocytotic machinery independently of intracellular Ca(2+). To explore the relevance of these interactions to secretion we exploited a BotC1-and a BotA-sensitive secretion system developed for Xenopus oocytes not buffered by BAPTA, in which depolarization-evoked secretion is monitored by a change in membrane capacitance. The reconstituted release mediated by Ca(V)2.1 is consistent with the model in which the VGCC plays a signaling role in triggering release, acting from within the exocytotic complex. The relevance of these results to secretion posits the role of possible rearrangements within the excitosome subsequent to Ca(2+) entry, setting the stage for the fusion of channel-tethered-vesicles upon the arrival of an action potential.

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“…It is well known that exocytosis is inhibited by clostridial toxins (Rosseto et al 2001; Aleu et al 2002). To analyse the possible exocytotic origin of ATP release we used tetanus neurotoxin (TeNT).…”

Section: Discussionmentioning

confidence: 99%

Release of ATP induced by hypertonic solutions in Xenopus oocytes

et al. 2003

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ATP mediates intercellular communication. Mechanical stress and changes in cell volume induce ATP release from various cell types, both secretory and non-secretory. In the present study, we stressed Xenopus oocytes with a hypertonic solution enriched in mannitol (300 mM). We measured simultaneously ATP release and ionic currents from a single oocyte. A decrease in cell volume, the activation of an inward current and ATP release were coincident. We found two components of ATP release: the first was associated with granule or vesicle exocytosis, because it was inhibited by tetanus neurotoxin, and the second was related to the inward current. A single exponential described the correlation between ATP release and the hypertonic-activated current. Gadolinium ions, which block mechanically activated ionic channels, inhibited the ATP release and the inward current but did not affect the decrease in volume. Oocytes expressing CFTR (cystic fibrosis transmembrane regulator) released ATP under hypertonic shock, but ATP release was significantly inhibited in the first component: that related to granule exocytosis. Since the ATP measured is the balance between ATP release and ATP degradation by ecto-enzymes, we measured the nucleoside triphosphate diphosphohydrolase (NTPDase) activity of the oocyte surface during osmotic stress, as the calciumdependent hydrolysis of ATP, which was inhibited by more than 50 % in hypertonic conditions. The best-characterized membrane protein showing NTPDase activity is CD39. Oocytes injected with an antisense oligonucleotide complementary to CD39 mRNA released less ATP and showed a lower amplitude in the inward current than those oocytes injected with water.

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Calcium‐dependent acetylcholine release from Xenopus oocytes: simultaneous ionic currents and acetylcholine release recordings

Cited by 15 publications

References 38 publications

The roles of maternal Vangl2 and aPKC inXenopusoocyte and embryo patterning

The roles of maternal Vangl2 and aPKC inXenopusoocyte and embryo patterning

Ca_V2.1 (P/Q channel) interaction with synaptic proteins is essential for depolarization-evoked release

Release of ATP induced by hypertonic solutions in Xenopus oocytes

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Calcium‐dependent acetylcholine release from Xenopus oocytes: simultaneous ionic currents and acetylcholine release recordings

Cited by 15 publications

References 38 publications

The roles of maternal Vangl2 and aPKC inXenopusoocyte and embryo patterning

The roles of maternal Vangl2 and aPKC inXenopusoocyte and embryo patterning

CaV2.1 (P/Q channel) interaction with synaptic proteins is essential for depolarization-evoked release

Release of ATP induced by hypertonic solutions in Xenopus oocytes

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Ca_V2.1 (P/Q channel) interaction with synaptic proteins is essential for depolarization-evoked release