scholarly journals Single-molecule analysis reveals the rapid effect of estradiol on the surface movement of AMPAR in live neurons

2019 ◽  
Author(s):  
Soma Godó ◽  
Klaudia Barabás ◽  
Ferenc Lengyel ◽  
Dávid Ernszt ◽  
Tamás Kovács ◽  
...  
Keyword(s):  
Single Molecule ◽  
Glutamatergic Neurotransmission ◽  
Gonadal Steroid ◽  
Actin Network ◽  
Cortical Actin ◽  
Surface Movement ◽  
Surface Mobility ◽  
Rapid Effect ◽  
17Β Estradiol ◽  
Single Molecule Analysis

AbstractThe gonadal steroid 17β-estradiol (E2) rapidly alters glutamatergic neurotransmission, but its direct effect on the AMPA receptor (AMPAR) remains unknown. Live-cell single-molecule imaging experiments revealed that E2 rapidly and dose-dependently alters the surface movement of AMPAR via membrane estrogen receptors with distinct effects on somas and neurites. The effect of E2 on the surface mobility of AMPAR depends on the integrity of the cortical actin network.

scholarly journals Single-Molecule Imaging Reveals Rapid Estradiol Action on the Surface Movement of AMPA Receptors in Live Neurons

2021 ◽  
Vol 9 ◽  
Author(s):  
Soma Godó ◽  
Klaudia Barabás ◽  
Ferenc Lengyel ◽  
Dávid Ernszt ◽  
Tamás Kovács ◽  
...  
Keyword(s):  
Single Molecule ◽  
Ampa Receptors ◽  
Imaging Techniques ◽  
Super Resolution ◽  
Dependent Manner ◽  
Glutamatergic Neurotransmission ◽  
Cortical Actin ◽  
Surface Movement ◽  
Surface Mobility ◽  
Genomic Effects

Gonadal steroid 17β-estradiol (E2) exerts rapid, non-genomic effects on neurons and strictly regulates learning and memory through altering glutamatergic neurotransmission and synaptic plasticity. However, its non-genomic effects on AMPARs are not well understood. Here, we analyzed the rapid effect of E2 on AMPARs using single-molecule tracking and super-resolution imaging techniques. We found that E2 rapidly decreased the surface movement of AMPAR via membrane G protein-coupled estrogen receptor 1 (GPER1) in neurites in a dose-dependent manner. The cortical actin network played a pivotal role in the GPER1 mediated effects of E2 on the surface mobility of AMPAR. E2 also decreased the surface movement of AMPAR both in synaptic and extrasynaptic regions on neurites and increased the synaptic dwell time of AMPARs. Our results provide evidence for understanding E2 action on neuronal plasticity and glutamatergic neurotransmission at the molecular level.

scholarly journals Coupled myosin VI motors facilitate unidirectional movement on an F-actin network

2009 ◽  
Vol 187 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Sivaraj Sivaramakrishnan ◽  
James A. Spudich
Keyword(s):  
Single Molecule ◽  
Membrane Trafficking ◽  
Cell Periphery ◽  
Myosin Vi ◽  
Actin Network ◽  
Cortical Actin ◽  
Actin Cortex ◽  
Unidirectional Movement ◽  
Transport Vesicle ◽  
Pointed End

Unconventional myosins interact with the dense cortical actin network during processes such as membrane trafficking, cell migration, and mechanotransduction. Our understanding of unconventional myosin function is derived largely from assays that examine the interaction of a single myosin with a single actin filament. In this study, we have developed a model system to study the interaction between multiple tethered unconventional myosins and a model F-actin cortex, namely the lamellipodium of a migrating fish epidermal keratocyte. Using myosin VI, which moves toward the pointed end of actin filaments, we directly determine the polarity of the extracted keratocyte lamellipodium from the cell periphery to the cell nucleus. We use a combination of experimentation and simulation to demonstrate that multiple myosin VI molecules can coordinate to efficiently transport vesicle-size cargo over 10 µm of the dense interlaced actin network. Furthermore, several molecules of monomeric myosin VI, which are nonprocessive in single molecule assays, can coordinate to transport cargo with similar speeds as dimers.

scholarly journals Dynamic multimerization of Dab2-Myosin VI complexes regulates cargo processivity while minimizing cortical actin reorganization

2020 ◽  
pp. jbc.RA120.012703
Author(s):  
Ashim Rai ◽  
Duha Vang ◽  
Michael Ritt ◽  
Sivaraj Sivaramakrishnan
Keyword(s):  
Lipid Bilayers ◽  
Single Molecule ◽  
High Rate ◽  
Myosin Vi ◽  
Actin Network ◽  
Cortical Actin ◽  
Myosin V ◽  
Kinetic Measurements ◽  
Actin Cortex ◽  
Run Lengths

Myosin VI ensembles on endocytic cargo facilitate directed transport through a dense cortical actin network. Myosin VI is recruited to clathrin-coated endosomes via the cargo adaptor Dab2. Canonically, it has been assumed that the interactions between a motor and its cargo adaptor are stable. However, it has been demonstrated that the force generated by multiple stably attached motors disrupts local cytoskeletal architecture, potentially compromising transport. In this study, we demonstrate that dynamic multimerization of myosin VI-Dab2 complexes facilitates cargo processivity without significant reorganization of cortical actin networks. Specifically, we find that Dab2 myosin interacting region (MIR) binds myosin VI with a moderate affinity (184 nM) and single molecule kinetic measurements demonstrate a high rate of turnover (1 s-1) of the Dab2 MIR-myosin VI interaction. Single molecule motility shows thatsaturating Dab2-MIR concentration (2 μM) promotes myosin VI homodimerization and processivity with run lengths comparable to constitutive myosin VI dimers. Cargo-mimetic DNA origami scaffolds patterned with Dab2 MIR-myosin VI complexes are weakly processive, displaying sparse motility on single actin filaments and “stop-and-go” motion on a cellular actin network. On a minimal actin cortex assembled on lipid bilayers, unregulated processive movement by either constitutive myosin V or VI dimers result in actin remodeling and foci formation. In contrast, Dab2 MIRmyosinVI interactions preserve the integrity of a minimal cortical actin network. Taken together, our study demonstrates the importance of dynamic motor-cargo association in enabling cargo transportation without disrupting cytoskeletal organization.

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