Botulinum neurotoxin A attenuates release of  norepinephrine but not NPY from vasoconstrictor neurons

We examined effects of botulinum neurotoxin A (BoNTA) on sympathetic constrictions of the vena cava and uterine artery from guinea pigs to test the role of soluble NSF attachment protein receptor (SNARE) proteins in release of the cotransmitters norepinephrine (NE) and neuropeptide Y (NPY). Protein extracts of venae cavae and uterine arteries showed partial cleavage of synaptosomal associated protein of 25 kDa (SNAP-25) after treatment in vitro with BoNTA (50–100 nM). The rising phase of isometric contractions of isolated venae cavae to field stimulation at 20 Hz, mediated by NE acting on α-adrenoceptors, was reduced significantly by 100 nM BoNTA. However, sustained sympathetic contractions mediated by NPY were not affected by BoNTA. In uterine arteries, noradrenergic contractions to 1-Hz stimulation were almost abolished by BoNTA, and contractions at 10 Hz were reduced by 50–60%. We conclude that SNARE proteins are involved in exocytosis of NE from synaptic vesicles at low frequencies of stimulation but may not be essential for exocytosis of NPY and NE from large vesicles at high stimulation frequencies.

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Differential inhibition by botulinum neurotoxin A of cotransmitters released from autonomic vasodilator neurons

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.2001.281.5.h2124 ◽

2001 ◽

Vol 281 (5) ◽

pp. H2124-H2132 ◽

Cited By ~ 80

Author(s):

Judy L. Morris ◽

Phillip Jobling ◽

Ian L. Gibbins

Keyword(s):

Botulinum Neurotoxin ◽

Snare Complex ◽

Snare Proteins ◽

Botulinum Neurotoxin A ◽

Uterine Arteries ◽

Synaptic Vesicle Exocytosis ◽

Protein Receptor ◽

Autonomic Neurons ◽

Vesicle Exocytosis

The role of the soluble NSF attachment protein receptor (SNARE) protein complex in release of multiple cotransmitters from autonomic vasodilator neurons was examined in isolated segments of guinea pig uterine arteries treated with botulinum neurotoxin A (BoNTA; 50 nM). Western blotting of protein extracts from uterine arteries demonstrated partial cleavage of synaptosomal-associated protein of 25 kDa (SNAP-25) to a NH2-terminal fragment of ∼24 kDa by BoNTA. BoNTA reduced the amplitude (by 70–80%) of isometric contractions of arteries in response to repeated electrical stimulation of sympathetic axons at 1 or 10 Hz. The amplitude of neurogenic relaxations mediated by neuronal nitric oxide (NO) was not affected by BoNTA, whereas the duration of peptide-mediated neurogenic relaxations to stimulation at 10 Hz was reduced (67% reduction in integrated responses). In contrast, presynaptic cholinergic inhibition of neurogenic relaxations was abolished by BoNTA. These results demonstrate that the SNARE complex has differential involvement in release of cotransmitters from the same autonomic neurons: NO release is not dependant on synaptic vesicle exocytosis, acetylcholine release from small vesicles is highly dependant on the SNARE complex, and neuropeptide release from large vesicles involves SNARE proteins that may interact differently with regulatory factors such as calcium.

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Sorting of GLUT4 into its insulin-sensitive store requires the Sec1/Munc18 protein mVps45

Molecular Biology of the Cell ◽

10.1091/mbc.e13-01-0011 ◽

2013 ◽

Vol 24 (15) ◽

pp. 2389-2397 ◽

Cited By ~ 13

Author(s):

Jennifer Roccisana ◽

Jessica B. A. Sadler ◽

Nia J. Bryant ◽

Gwyn W. Gould

Keyword(s):

Glucose Transport ◽

Glucose Transporter ◽

Vitro Assay ◽

Protein Receptor ◽

Storage Vesicles ◽

Storage Vesicle ◽

Impaired Insulin ◽

Endosomal Pathway

Insulin stimulates glucose transport in fat and muscle cells by regulating delivery of the facilitative glucose transporter, glucose transporter isoform 4 (GLUT4), to the plasma membrane. In the absence of insulin, GLUT4 is sequestered away from the general recycling endosomal pathway into specialized vesicles, referred to as GLUT4-storage vesicles. Understanding the sorting of GLUT4 into this store is a major challenge. Here we examine the role of the Sec1/Munc18 protein mVps45 in GLUT4 trafficking. We show that mVps45 is up-regulated upon differentiation of 3T3-L1 fibroblasts into adipocytes and is expressed at stoichiometric levels with its cognate target–soluble N-ethylmaleimide–sensitive factor attachment protein receptor, syntaxin 16. Depletion of mVps45 in 3T3-L1 adipocytes results in decreased GLUT4 levels and impaired insulin-stimulated glucose transport. Using subcellular fractionation and an in vitro assay for GLUT4-storage vesicle formation, we show that mVps45 is required to correctly traffic GLUT4 into this compartment. Collectively our data reveal a crucial role for mVps45 in the delivery of GLUT4 into its specialized, insulin-regulated compartment.

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Multi-wavelength spatial LED illumination based detector for in vitro detection of botulinum neurotoxin A activity

Sensors and Actuators B Chemical ◽

10.1016/j.snb.2010.02.009 ◽

2010 ◽

Vol 146 (1) ◽

pp. 297-306 ◽

Cited By ~ 26

Author(s):

Steven Sun ◽

Jesse Francis ◽

Kim E. Sapsford ◽

Yordan Kostov ◽

Avraham Rasooly

Keyword(s):

Botulinum Neurotoxin ◽

Botulinum Neurotoxin A ◽

Multi Wavelength

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SV2 Is the Protein Receptor for Botulinum Neurotoxin A

Science ◽

10.1126/science.1123654 ◽

2006 ◽

Vol 312 (5773) ◽

pp. 592-596 ◽

Cited By ~ 501

Author(s):

M. Dong

Keyword(s):

Botulinum Neurotoxin ◽

Botulinum Neurotoxin A ◽

Protein Receptor

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Selective corticostriatal plasticity during acquisition of an auditory discrimination task

10.1101/010066 ◽

2014 ◽

Cited By ~ 1

Author(s):

Qiaojie Xiong ◽

Petr Znamenskiy ◽

Anthony Zador

Keyword(s):

Cortical Neurons ◽

Brain Slices ◽

Frequency Discrimination ◽

Auditory Discrimination ◽

Low Frequencies ◽

Reward Contingencies ◽

Corticostriatal Plasticity

Perceptual decisions are based on the activity of sensory cortical neurons, but how organisms learn to transform this activity into appropriate actions remains unknown. Projections from the auditory cortex to the auditory striatum carry information that drives decisions in an auditory frequency discrimination task1. To assess the role of these projections in learning, we developed a Channelrhodopsin-2-based assay to selectively probe for synaptic plasticity associated with corticostriatal neurons representing different frequencies. Here we report that learning this auditory discrimination preferentially potentiates corticostriatal synapses from neurons representing either high or low frequencies, depending on reward contingencies. We observed frequency-dependent corticostriatal potentiation in vivo over the course of training, and in vitro in striatal brain slices. Our findings suggest a model in which selective potentiation of inputs representing different components of a sensory stimulus enables the learned transformation of sensory input into actions.

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Reconciling the regulatory role of Munc18 proteins in SNARE-complex assembly

IUCrJ ◽

10.1107/s2052252514020727 ◽

2014 ◽

Vol 1 (6) ◽

pp. 505-513 ◽

Cited By ~ 12

Author(s):

Asma Rehman ◽

Julia K. Archbold ◽

Shu-Hong Hu ◽

Suzanne J. Norwood ◽

Brett M. Collins ◽

...

Keyword(s):

Membrane Fusion ◽

Transmembrane Domain ◽

Blood Glucose Control ◽

Vital Role ◽

Snare Complex ◽

Snare Proteins ◽

Regulatory Role ◽

Sm Proteins ◽

Protein Receptor

Membrane fusion is essential for human health, playing a vital role in processes as diverse as neurotransmission and blood glucose control. Two protein families are key: (1) the Sec1p/Munc18 (SM) and (2) the solubleN-ethylmaleimide-sensitive attachment protein receptor (SNARE) proteins. Whilst the essential nature of these proteins is irrefutable, their exact regulatory roles in membrane fusion remain controversial. In particular, whether SM proteins promote and/or inhibit the SNARE-complex formation required for membrane fusion is not resolved. Crystal structures of SM proteins alone and in complex with their cognate SNARE proteins have provided some insight, however, these structures lack the transmembrane spanning regions of the SNARE proteins and may not accurately reflect the native state. Here, we review the literature surrounding the regulatory role of mammalian Munc18 SM proteins required for exocytosis in eukaryotes. Our analysis suggests that the conflicting roles reported for these SM proteins may reflect differences in experimental design. SNARE proteins appear to require C-terminal immobilization or anchoring, for example through a transmembrane domain, to form a functional fusion complex in the presence of Munc18 proteins.

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