scholarly journals Intersectin associates with synapsin and regulates its nanoscale localization and function

2017 ◽  
Vol 114 (45) ◽  
pp. 12057-12062 ◽  
Author(s):  
Fabian Gerth ◽  
Maria Jäpel ◽  
Arndt Pechstein ◽  
Gaga Kochlamazashvili ◽  
Martin Lehmann ◽  
...  
Keyword(s):  
Synaptic Vesicles ◽  
Synapsin I ◽  
Wild Type ◽  
Src Homology 3 ◽  
Reserve Pool ◽  
Hippocampal Synapses ◽  
Important Regulator ◽  
Src Homology ◽  
Elevated Activity ◽  
And Function

Neurotransmission is mediated by the exocytic release of neurotransmitters from readily releasable synaptic vesicles (SVs) at the active zone. To sustain neurotransmission during periods of elevated activity, release-ready vesicles need to be replenished from the reserve pool of SVs. The SV-associated synapsins are crucial for maintaining this reserve pool and regulate the mobilization of reserve pool SVs. How replenishment of release-ready SVs from the reserve pool is regulated and which other factors cooperate with synapsins in this process is unknown. Here we identify the endocytic multidomain scaffold protein intersectin as an important regulator of SV replenishment at hippocampal synapses. We found that intersectin directly associates with synapsin I through its Src-homology 3 A domain, and this association is regulated by an intramolecular switch within intersectin 1. Deletion of intersectin 1/2 in mice alters the presynaptic nanoscale distribution of synapsin I and causes defects in sustained neurotransmission due to defective SV replenishment. These phenotypes were rescued by wild-type intersectin 1 but not by a locked mutant of intersectin 1. Our data reveal intersectin as an autoinhibited scaffold that serves as a molecular linker between the synapsin-dependent reserve pool and the presynaptic endocytosis machinery.

scholarly journals MYH10 governs adipocyte function and adipogenesis through its interaction with GLUT4

2021 ◽  
Author(s):  
N Kislev ◽  
L Mor-Yossef Moldovan ◽  
R Barak ◽  
M Egozi ◽  
D Benayahu
Keyword(s):  
Glucose Transporter ◽  
Cytoskeletal Proteins ◽  
Wild Type ◽  
Cytoskeletal Remodeling ◽  
Kinase C ◽  
Important Regulator ◽  
Insulin Dependent ◽  
And Function ◽  
Cellular Components ◽  
Muscle Myosin

AbstractAdipocyte differentiation is dependent on cytoskeletal remodeling processes that determine and maintain cellular shape and function. In turn, cytoskeletal proteins contribute to the filament-based network responsible for controlling adipocyte’s shape and promoting the intracellular trafficking of key cellular components. Currently, our understanding of these mechanisms remains incomplete. In this study, we identified the non-muscle myosin 10 (MYH10) as an important regulator of adipogenesis and adipocyte function through its interaction with the insulin dependent, Glucose transporter 4 (GLUT4). MYH10 depletion in preadipocytes resulted in impaired adipogenesis, with knockdown cells exhibiting disrupted morphology and reduced molecular adipogenic signals. MYH10 was shown to be in complex with GLUT4 in adipocytes, an interaction regulated by insulin induction. The missing adipogenic capacity of MYH10-KD cells was restored when they uptook GLUT4 vesicles up from neighbor wild-type cells in a co-culture system. Our results provide the first demonstration that MYH10 interacts with GLUT4 in cells and adipose tissue through the insulin pathway. The signaling cascade is regulated by the protein kinase C ζ (PKCζ), which interacts with MYH10 to modify the localization and interaction of both GLUT4 and MYH10 in adipocytes as PKCζ inhibition resulted in reduced GLUT4 and MYH10 translocation and interactions. Overall, our study establishes MYH10 as an essential regulator of GLUT4 translocation, affecting both adipogenesis and adipocyte function, highlighting its importance in future cytoskeleton-based studies in adipocytes.

scholarly journals Normal Biogenesis and Cycling of Empty Synaptic Vesicles in Dopamine Neurons of Vesicular Monoamine Transporter 2 Knockout Mice

2005 ◽  
Vol 16 (1) ◽  
pp. 306-315 ◽  
Author(s):  
Benjamin G. Croft ◽  
Gabriel D. Fortin ◽  
Amadou T. Corera ◽  
Robert H. Edwards ◽  
Alain Beaudet ◽  
...  
Keyword(s):  
Synaptic Vesicle ◽  
Knockout Mice ◽  
Synaptic Vesicles ◽  
Dopamine Neurons ◽  
Vesicular Monoamine Transporter ◽  
Wild Type ◽  
Monoamine Transporter ◽  
Vesicle Biogenesis ◽  
And Function ◽  
Activity Dependent

The neuronal isoform of vesicular monoamine transporter, VMAT2, is responsible for packaging dopamine and other monoamines into synaptic vesicles and thereby plays an essential role in dopamine neurotransmission. Dopamine neurons in mice lacking VMAT2 are unable to store or release dopamine from their synaptic vesicles. To determine how VMAT2-mediated filling influences synaptic vesicle morphology and function, we examined dopamine terminals from VMAT2 knockout mice. In contrast to the abnormalities reported in glutamatergic terminals of mice lacking VGLUT1, the corresponding vesicular transporter for glutamate, we found that the ultrastructure of dopamine terminals and synaptic vesicles in VMAT2 knockout mice were indistinguishable from wild type. Using the activity-dependent dyes FM1-43 and FM2-10, we also found that synaptic vesicles in dopamine neurons lacking VMAT2 undergo endocytosis and exocytosis with kinetics identical to those seen in wild-type neurons. Together, these results demonstrate that dopamine synaptic vesicle biogenesis and cycling are independent of vesicle filling with transmitter. By demonstrating that such empty synaptic vesicles can cycle at the nerve terminal, our study suggests that physiological changes in VMAT2 levels or trafficking at the synapse may regulate dopamine release by altering the ratio of fillable-to-empty synaptic vesicles, as both continue to cycle in response to neural activity.

scholarly journals Interaction of Grb2 via its Src homology 3 domains with synaptic proteins including synapsin I.

1994 ◽  
Vol 91 (14) ◽  
pp. 6486-6490 ◽  
Author(s):  
P. S. McPherson ◽  
A. J. Czernik ◽  
T. J. Chilcote ◽  
F. Onofri ◽  
F. Benfenati ◽  
...  
Keyword(s):  
Synaptic Proteins ◽  
Synapsin I ◽  
Src Homology 3 ◽  
Src Homology

scholarly journals O-Linked β-N-Acetylglucosamine (O-GlcNAc) Site Thr-87 Regulates Synapsin I Localization to Synapses and Size of the Reserve Pool of Synaptic Vesicles

2013 ◽  
Vol 289 (6) ◽  
pp. 3602-3612 ◽  
Author(s):  
Yuliya Skorobogatko ◽  
Ashly Landicho ◽  
Robert J. Chalkley ◽  
Andrew V. Kossenkov ◽  
Gianluca Gallo ◽  
...  
Keyword(s):  
Synaptic Vesicles ◽  
Synapsin I ◽  
Reserve Pool

scholarly journals Specificity of the Binding of Synapsin I to Src Homology 3 Domains

2000 ◽  
Vol 275 (38) ◽  
pp. 29857-29867 ◽  
Author(s):  
Franco Onofri ◽  
Silvia Giovedı̀ ◽  
Hung-Teh Kao ◽  
Flavia Valtorta ◽  
Lucilla Bongiorno Borbone ◽  
...  
Keyword(s):  
Synapsin I ◽  
Src Homology 3 ◽  
Src Homology

scholarly journals Munc13 controls the location and efficiency of dense-core vesicle release in neurons

2012 ◽  
Vol 199 (6) ◽  
pp. 883-891 ◽  
Author(s):  
Rhea van de Bospoort ◽  
Margherita Farina ◽  
Sabine K. Schmitz ◽  
Arthur de Jong ◽  
Heidi de Wit ◽  
...  
Keyword(s):  
Synaptic Vesicles ◽  
Hippocampal Neurons ◽  
Dense Core ◽  
Dense Core Vesicle ◽  
Wild Type ◽  
Vesicle Release ◽  
Prolonged Stimulation ◽  
And Function ◽  
Activity Dependent ◽  
Single Vesicle

Neuronal dense-core vesicles (DCVs) contain diverse cargo crucial for brain development and function, but the mechanisms that control their release are largely unknown. We quantified activity-dependent DCV release in hippocampal neurons at single vesicle resolution. DCVs fused preferentially at synaptic terminals. DCVs also fused at extrasynaptic sites but only after prolonged stimulation. In munc13-1/2–null mutant neurons, synaptic DCV release was reduced but not abolished, and synaptic preference was lost. The remaining fusion required prolonged stimulation, similar to extrasynaptic fusion in wild-type neurons. Conversely, Munc13-1 overexpression (M13OE) promoted extrasynaptic DCV release, also without prolonged stimulation. Thus, Munc13-1/2 facilitate DCV fusion but, unlike for synaptic vesicles, are not essential for DCV release, and M13OE is sufficient to produce efficient DCV release extrasynaptically.

scholarly journals A high affinity RIM-binding protein/Aplip1 interaction prevents the formation of ectopic axonal active zones

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Matthias Siebert ◽  
Mathias A Böhme ◽  
Jan H Driller ◽  
Husam Babikir ◽  
Malou M Mampell ◽  
...  
Keyword(s):  
Synaptic Vesicles ◽  
Protein Transport ◽  
Binding Protein ◽  
Sh3 Domains ◽  
Src Homology 3 ◽  
High Affinity ◽  
Pxxp Motif ◽  
Transport Mutants ◽  
Src Homology ◽  
Active Zones

Synaptic vesicles (SVs) fuse at active zones (AZs) covered by a protein scaffold, at Drosophila synapses comprised of ELKS family member Bruchpilot (BRP) and RIM-binding protein (RBP). We here demonstrate axonal co-transport of BRP and RBP using intravital live imaging, with both proteins co-accumulating in axonal aggregates of several transport mutants. RBP, via its C-terminal Src-homology 3 (SH3) domains, binds Aplip1/JIP1, a transport adaptor involved in kinesin-dependent SV transport. We show in atomic detail that RBP C-terminal SH3 domains bind a proline-rich (PxxP) motif of Aplip1/JIP1 with submicromolar affinity. Pointmutating this PxxP motif provoked formation of ectopic AZ-like structures at axonal membranes. Direct interactions between AZ proteins and transport adaptors seem to provide complex avidity and shield synaptic interaction surfaces of pre-assembled scaffold protein transport complexes, thus, favouring physiological synaptic AZ assembly over premature assembly at axonal membranes.

scholarly journals Reengineering biocatalysts: Computational redesign of chondroitinase ABC improves efficacy and stability

2020 ◽  
Vol 6 (34) ◽  
pp. eabc6378
Author(s):  
Marian H. Hettiaratchi ◽  
Matthew J. O’Meara ◽  
Teresa R. O’Meara ◽  
Andrew J. Pickering ◽  
Nitzan Letko-Khait ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Amino Acid ◽  
Wild Type ◽  
Chondroitinase Abc ◽  
Cns Regeneration ◽  
Src Homology 3 ◽  
Src Homology ◽  
Binding Peptides ◽  
Critical Challenge

Maintaining biocatalyst stability and activity is a critical challenge. Chondroitinase ABC (ChABC) has shown promise in central nervous system (CNS) regeneration, yet its therapeutic utility is severely limited by instability. We computationally reengineered ChABC by introducing 37, 55, and 92 amino acid changes using consensus design and forcefield-based optimization. All mutants were more stable than wild-type ChABC with increased aggregation temperatures between 4° and 8°C. Only ChABC with 37 mutations (ChABC-37) was more active and had a 6.5 times greater half-life than wild-type ChABC, increasing to 106 hours (4.4 days) from only 16.8 hours. ChABC-37, expressed as a fusion protein with Src homology 3 (ChABC-37-SH3), was active for 7 days when released from a hydrogel modified with SH3-binding peptides. This study demonstrates the broad opportunity to improve biocatalysts through computational engineering and sets the stage for future testing of this substantially improved protein in the treatment of debilitating CNS injuries.

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