Microdomains of SNARE Proteins in the Plasma Membrane

2013 ◽  
pp. 193-230 ◽  
Author(s):  
Geert van den Bogaart ◽  
Thorsten Lang ◽  
Reinhard Jahn
Keyword(s):  
Plasma Membrane ◽  
Snare Proteins

Mechanisms of CFTR regulation by syntaxin 1A and PKA

2002 ◽  
Vol 115 (4) ◽  
pp. 783-791 ◽  
Author(s):  
Steven Y. Chang ◽  
Anke Di ◽  
Anjaparavanda P. Naren ◽  
H. Clive Palfrey ◽  
Kevin L. Kirk ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Protein Interactions ◽  
Membrane Trafficking ◽  
Anion Channel ◽  
Cell Types ◽  
Snare Proteins ◽  
Snare Protein ◽  
Membrane Turnover ◽  
Open Probability ◽  
Syntaxin 1A

Activation of the chloride selective anion channel CFTR is stimulated by cAMP-dependent phosphorylation and is regulated by the target membrane t-SNARE syntaxin 1A. The mechanism by which SNARE proteins modulate CFTR in secretory epithelia is controversial. In addition, controversy exists as to whether PKA activates CFTR-mediated Cl- currents (ICFTR) by increasing the number of channels in the plasma membrane and/or by stimulating membrane-resident channels. SNARE proteins play a well known role in exocytosis and have recently been implicated in the regulation of ion channels; therefore this investigation sought to resolve two related issues:(a) is PKA activation or SNARE protein modulation of CFTR linked to changes in membrane turnover and (b) does syntaxin 1A modulate CFTR via direct effects on the gating of channels residing in the plasma membrane versus alterations in membrane traffic. Our data demonstrate that syntaxin 1A inhibits CFTR as a result of direct protein-protein interactions that decrease channel open probability (Po) and serves as a model for other SNARE protein-ion channel interactions. We also show that PKA activation can enhance membrane trafficking in some epithelial cell types, and this is independent from CFTR activation or syntaxin 1A association.

scholarly journals A Role for VAMP8/Endobrevin in Surface Deployment of the Water Channel Aquaporin 2

2009 ◽  
Vol 30 (1) ◽  
pp. 333-343 ◽  
Author(s):  
Cheng-Chun Wang ◽  
Chee Peng Ng ◽  
Hong Shi ◽  
Hwee Chien Liew ◽  
Ke Guo ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Protein ◽  
Collecting Duct ◽  
Water Channel ◽  
Snare Proteins ◽  
Snare Protein ◽  
Aquaporin 2 ◽  
Duct Cells ◽  
Collecting Duct Cells ◽  
Intracellular Vesicles

ABSTRACT Vesicle-associated-membrane protein 8 (VAMP8) is highly expressed in the kidney, but the exact physiological and molecular functions executed by this v-SNARE protein in nephrons remain elusive. Here, we show that the depletion of VAMP8 in mice resulted in hydronephrosis. Furthermore, the level of the vasopressin-responsive water channel aquaporin 2 (AQP2) was increased by three- to fivefold in VAMP8-null mice. Forskolin and [desamino-Cys1, D-Arg8]-vasopressin (DDAVP)-induced AQP2 exocytosis was impaired in VAMP8-null collecting duct cells. VAMP8 was revealed to colocalize with AQP2 on intracellular vesicles and to interact with the plasma membrane t-SNARE proteins syntaxin4 and syntaxin3, suggesting that VAMP8 mediates the regulated fusion of AQP2-positive vesicles with the plasma membrane.

scholarly journals Restriction of Secretory Granule Motion near the Plasma Membrane of Chromaffin Cells

2001 ◽  
Vol 153 (1) ◽  
pp. 177-190 ◽  
Author(s):  
Laura M. Johns ◽  
Edwin S. Levitan ◽  
Eric A. Shelden ◽  
Ronald W. Holz ◽  
Daniel Axelrod
Keyword(s):  
Plasma Membrane ◽  
Total Internal Reflection ◽  
Chromaffin Cells ◽  
Botulinum Toxin A ◽  
Secretory Granules ◽  
Internal Reflection ◽  
Snare Proteins ◽  
Bovine Chromaffin Cells ◽  
Heterogeneous Matrix ◽  
Granule Motion

We used total internal reflection fluorescence microscopy to study quantitatively the motion and distribution of secretory granules near the plasma membrane (PM) of living bovine chromaffin cells. Within the ∼300-nm region measurably illuminated by the evanescent field resulting from total internal reflection, granules are preferentially concentrated close to the PM. Granule motion normal to the substrate (the z direction) is much slower than would be expected from free Brownian motion, is strongly restricted over tens of nanometer distances, and tends to reverse directions within 0.5 s. The z-direction diffusion coefficients of granules decrease continuously by two orders of magnitude within less than a granule diameter of the PM as granules approach the PM. These analyses suggest that a system of tethers or a heterogeneous matrix severely limits granule motion in the immediate vicinity of the PM. Transient expression of the light chains of tetanus toxin and botulinum toxin A did not disrupt the restricted motion of granules near the PM, indicating that SNARE proteins SNAP-25 and VAMP are not necessary for the decreased mobility. However, the lack of functional SNAREs on the plasma or granule membranes in such cells reduces the time that some granules spend immediately adjacent to the PM.

Subcellular distribution of 3 functional platelet SNARE proteins: human cellubrevin, SNAP-23, and syntaxin 2

Blood ◽  
2002 ◽  
Vol 99 (11) ◽  
pp. 4006-4014 ◽  
Author(s):  
Dian Feng ◽  
Katharine Crane ◽  
Nataliya Rozenvayn ◽  
Ann M. Dvorak ◽  
Robert Flaumenhaft
Keyword(s):  
Plasma Membrane ◽  
Subcellular Distribution ◽  
Molecular Mechanisms ◽  
Protein Composition ◽  
Immunoblot Analysis ◽  
Snare Proteins ◽  
Ultrastructural Studies ◽  
Streptolysin O ◽  
Membrane Compartments ◽  
Granule Secretion

Morphologic studies have demonstrated a process by which α-granule contents are released from platelets. Studies aimed at defining the molecular mechanisms of this release have demonstrated that SNARE proteins are required for α-granule secretion. These observations raise the possibility that morphologic features of α-granule secretion may be influenced by the subcellular distribution of SNARE proteins in the platelet. To evaluate this possibility, we analyzed the subcellular distribution of 3 functional platelet SNARE proteins—human cellubrevin, SNAP-23, and syntaxin 2. Exposure of streptolysin O-permeabilized platelets to antihuman cellubrevin antibody inhibited Ca++-induced α-granule secretion by approximately 50%. Inhibition of α-granule secretion by antihuman cellubrevin was reversed by a blocking peptide. Syntaxin 2 and SNAP-23 have previously been demonstrated to mediate platelet granule secretion. The subcellular localization of the 3 SNARE proteins was determined by ultrastructural studies, using a pre-embedding immunonanogold method, and by immunoblot analysis of subcellular fractions. Immunonanogold localization demonstrated that approximately 80% of human cellubrevin in resting platelets was localized to platelet granule membranes. In contrast, SNAP-23 localized predominantly to plasma membrane, whereas syntaxin 2 was more evenly distributed among membranes of α-granules, the open canalicular system, and plasma membrane. Thus, each of these SNARE proteins has a distinct subcellular distribution in platelets, and each of these membrane compartments demonstrates a unique SNARE protein composition. This distribution provides a basis for several characteristics of α-granule secretion that include homotypic α-granule fusion and the fusion of α-granules with the open canalicular system and plasma membrane.

scholarly journals AP180-Mediated Trafficking of Vamp7B Limits Homotypic Fusion of Dictyostelium Contractile Vacuoles

2009 ◽  
Vol 20 (20) ◽  
pp. 4278-4288 ◽  
Author(s):  
Yujia Wen ◽  
Irene Stavrou ◽  
Kirill Bersuker ◽  
Rebecca J. Brady ◽  
Arturo De Lozanne ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Coated Vesicles ◽  
Contractile Vacuole ◽  
Snare Proteins ◽  
In Vitro Assays ◽  
Accessory Proteins ◽  
Coated Pits ◽  
Contractile Vacuoles ◽  
Null Mutants

Clathrin-coated vesicles play an established role in endocytosis from the plasma membrane, but they are also found on internal organelles. We examined the composition of clathrin-coated vesicles on an internal organelle responsible for osmoregulation, the Dictyostelium discoideum contractile vacuole. Clathrin puncta on contractile vacuoles contained multiple accessory proteins typical of plasma membrane–coated pits, including AP2, AP180, and epsin, but not Hip1r. To examine how these clathrin accessory proteins influenced the contractile vacuole, we generated cell lines that carried single and double gene knockouts in the same genetic background. Single or double mutants that lacked AP180 or AP2 exhibited abnormally large contractile vacuoles. The enlarged contractile vacuoles in AP180-null mutants formed because of excessive homotypic fusion among contractile vacuoles. The SNARE protein Vamp7B was mislocalized and enriched on the contractile vacuoles of AP180-null mutants. In vitro assays revealed that AP180 interacted with the cytoplasmic domain of Vamp7B. We propose that AP180 directs Vamp7B into clathrin-coated vesicles on contractile vacuoles, creating an efficient mechanism for regulating the internal distribution of fusion-competent SNARE proteins and limiting homotypic fusions among contractile vacuoles. Dictyostelium contractile vacuoles offer a valuable system to study clathrin-coated vesicles on internal organelles within eukaryotic cells.

scholarly journals The mesoscale organization of syntaxin 1A and SNAP25 is determined by SNARE-SNARE-interactions

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Jasmin Mertins ◽  
Jérôme Finke ◽  
Ricarda Antonia Sies ◽  
Kerstin Rink ◽  
Jan Hasenauer ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Fusion ◽  
Secretory Pathway ◽  
Snare Proteins ◽  
Strong Interactions ◽  
Dependent Manner ◽  
Syntaxin 1A ◽  
Membrane Area ◽  
Cellular Processes ◽  
Domain Interactions

SNARE proteins have been described as the effectors of fusion events in the secretory pathway more than two decades ago. The strong interactions between SNARE-domains are clearly important in membrane fusion, but it is unclear whether they are involved in any other cellular processes. Here, we analyzed two classical SNARE proteins, syntaxin 1A and SNAP25. Although they are supposed to be engaged in tight complexes, we surprisingly find them largely segregated in the plasma membrane. Syntaxin 1A only occupies a small fraction of the plasma membrane area. Yet, we find it is able to redistribute the far more abundant SNAP25 on the mesoscale by gathering crowds of SNAP25 molecules onto syntaxin-clusters in a SNARE-domain dependent manner. Our data suggests that SNARE-domain interactions are not only involved in driving membrane fusion on the nanoscale, but also play an important role in controlling the general organization of proteins on the mesoscale. Further, we propose this mechanisms preserves active syntaxin 1A-SNAP25 complexes at the plasma membrane.

scholarly journals A Second SNARE Role for Exocytic SNAP25 in Endosome Fusion

2006 ◽  
Vol 17 (5) ◽  
pp. 2113-2124 ◽  
Author(s):  
Yoshikatsu Aikawa ◽  
Kara L. Lynch ◽  
Kristin L. Boswell ◽  
Thomas F.J. Martin
Keyword(s):  
Plasma Membrane ◽  
Membrane Fusion ◽  
Secretory Vesicle ◽  
Neuroendocrine Cells ◽  
Snare Complex ◽  
Snare Proteins ◽  
Recycling Endosome ◽  
Protein Receptor ◽  
Interfering Rna

Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins play key roles in membrane fusion, but their sorting to specific membranes is poorly understood. Moreover, individual SNARE proteins can function in multiple membrane fusion events dependent upon their trafficking itinerary. Synaptosome-associated protein of 25 kDa (SNAP25) is a plasma membrane Q (containing glutamate)-SNARE essential for Ca2+-dependent secretory vesicle–plasma membrane fusion in neuroendocrine cells. However, a substantial intracellular pool of SNAP25 is maintained by endocytosis. To assess the role of endosomal SNAP25, we expressed botulinum neurotoxin E (BoNT E) light chain in PC12 cells, which specifically cleaves SNAP25. BoNT E expression altered the intracellular distribution of SNAP25, shifting it from a perinuclear recycling endosome to sorting endosomes, which indicates that SNAP25 is required for its own endocytic trafficking. The trafficking of syntaxin 13 and endocytosed cargo was similarly disrupted by BoNT E expression as was an endosomal SNARE complex comprised of SNAP25/syntaxin 13/vesicle-associated membrane protein 2. The small-interfering RNA-mediated down-regulation of SNAP25 exerted effects similar to those of BoNT E expression. Our results indicate that SNAP25 has a second function as an endosomal Q-SNARE in trafficking from the sorting endosome to the recycling endosome and that BoNT E has effects linked to disruption of the endosome recycling pathway.

scholarly journals Plasma membrane targeting of exocytic SNARE proteins

2004 ◽  
Vol 1693 (2) ◽  
pp. 81-89 ◽  
Author(s):  
Christine Salaün ◽  
Declan J James ◽  
Jennifer Greaves ◽  
Luke H Chamberlain
Keyword(s):  
Plasma Membrane ◽  
Snare Proteins ◽  
Membrane Targeting
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