scholarly journals Optical Switching Between Long‐lived States of Opsin Transmembrane Voltage Sensors

2021 ◽  
Author(s):  
Gaoxiang Mei ◽  
Cesar M. Cavini ◽  
Natalia Mamaeva ◽  
Peng Wang ◽  
Willem J. DeGrip ◽  
...  
Keyword(s):  
Optical Switching ◽  
Voltage Sensors ◽  
Transmembrane Voltage

scholarly journals Analog Retinal Redshifts Visible Absorption of QuasAr Transmembrane Voltage Sensors into Near‐infrared

2019 ◽  
Vol 96 (1) ◽  
pp. 55-66
Author(s):  
Gaoxiang Mei ◽  
Natalia Mamaeva ◽  
Srividya Ganapathy ◽  
Peng Wang ◽  
Willem J. DeGrip ◽  
...  
Keyword(s):  
Near Infrared ◽  
Visible Absorption ◽  
Voltage Sensors ◽  
Transmembrane Voltage

scholarly journals Regulation of Eag1 gating by its intracellular domains

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Jonathan R Whicher ◽  
Roderick MacKinnon
Keyword(s):  
Potassium Channels ◽  
Membrane Voltage ◽  
Specific Interactions ◽  
Voltage Sensors ◽  
Voltage Gated ◽  
Open Conformation ◽  
Channel Opening ◽  
Transmembrane Voltage ◽  
Voltage Dependent ◽  
Intracellular Domains

Voltage-gated potassium channels (Kvs) are gated by transmembrane voltage sensors (VS) that move in response to changes in membrane voltage. Kv10.1 or Eag1 also has three intracellular domains: PAS, C-linker, and CNBHD. We demonstrate that the Eag1 intracellular domains are not required for voltage-dependent gating but likely interact with the VS to modulate gating. We identified specific interactions between the PAS, CNBHD, and VS that modulate voltage-dependent gating and provide evidence that VS movement destabilizes these interactions to promote channel opening. Additionally, mutation of these interactions renders Eag1 insensitive to calmodulin inhibition. The structure of the calmodulin insensitive mutant in a pre-open conformation suggests that channel opening may occur through a rotation of the intracellular domains and calmodulin may prevent this rotation by stabilizing interactions between the VS and intracellular domains. Intracellular domains likely play a similar modulatory role in voltage-dependent gating of the related Kv11-12 channels.

scholarly journals Deletion of cytosolic gating ring decreases gate and voltage sensor coupling in BK channels

2017 ◽  
Vol 149 (3) ◽  
pp. 373-387 ◽  
Author(s):  
Guohui Zhang ◽  
Yanyan Geng ◽  
Yakang Jin ◽  
Jingyi Shi ◽  
Kelli McFarland ◽  
...  
Keyword(s):  
Bk Channels ◽  
Bk Channel ◽  
Voltage Sensor ◽  
Voltage Sensitivity ◽  
Gating Currents ◽  
Voltage Sensors ◽  
Transmembrane Voltage ◽  
Wide Range ◽  
Activation Gate ◽  
Sensor Activation

Large conductance Ca2+-activated K+ channels (BK channels) gate open in response to both membrane voltage and intracellular Ca2+. The channel is formed by a central pore-gate domain (PGD), which spans the membrane, plus transmembrane voltage sensors and a cytoplasmic gating ring that acts as a Ca2+ sensor. How these voltage and Ca2+ sensors influence the common activation gate, and interact with each other, is unclear. A previous study showed that a BK channel core lacking the entire cytoplasmic gating ring (Core-MT) was devoid of Ca2+ activation but retained voltage sensitivity (Budelli et al. 2013. Proc. Natl. Acad. Sci. USA. http://dx.doi.org/10.1073/pnas.1313433110). In this study, we measure voltage sensor activation and pore opening in this Core-MT channel over a wide range of voltages. We record gating currents and find that voltage sensor activation in this truncated channel is similar to WT but that the coupling between voltage sensor activation and gating of the pore is reduced. These results suggest that the gating ring, in addition to being the Ca2+ sensor, enhances the effective coupling between voltage sensors and the PGD. We also find that removal of the gating ring alters modulation of the channels by the BK channel’s β1 and β2 subunits.

Nanostructure of semiconductor quantum dots in a borosilicate glass matrix by complementary use of HREM and AEM

1990 ◽  
Vol 48 (4) ◽  
pp. 728-729
Author(s):  
M.J. Kim ◽  
L.C. Liu ◽  
S.H. Risbud ◽  
R.W. Carpenter
Keyword(s):  
Quantum Dots ◽  
Borosilicate Glass ◽  
Glass Matrix ◽  
Optical Switching ◽  
Response Times ◽  
Fast Response ◽  
Processing Technique ◽  
Internal Stresses ◽  
Electron Hole ◽  
Spatial Dimensions

When the size of a semiconductor is reduced by an appropriate materials processing technique to a dimension less than about twice the radius of an exciton in the bulk crystal, the band like structure of the semiconductor gives way to discrete molecular orbital electronic states. Clusters of semiconductors in a size regime lower than 2R {where R is the exciton Bohr radius; e.g. 3 nm for CdS and 7.3 nm for CdTe) are called Quantum Dots (QD) because they confine optically excited electron- hole pairs (excitons) in all three spatial dimensions. Structures based on QD are of great interest because of fast response times and non-linearity in optical switching applications.In this paper we report the first HREM analysis of the size and structure of CdTe and CdS QD formed by precipitation from a modified borosilicate glass matrix. The glass melts were quenched by pouring on brass plates, and then annealed to relieve internal stresses. QD precipitate particles were formed during subsequent "striking" heat treatments above the glass crystallization temperature, which was determined by differential thermal analysis.

Optical Switching Networks

2008 ◽  
Author(s):  
Martin Maier
Keyword(s):  
Optical Switching ◽  
Switching Networks ◽  
Optical Switching Networks

On Number of Planes of Rearrangeably Nonblocking Optical Banyan Networks with Link Failures

2008 ◽  
Vol 1 (1) ◽  
pp. 43-54
Author(s):  
Basra Sultana ◽  
Mamun-ur-Rashid Khandker
Keyword(s):  
Optical Switching ◽  
Blocking Probability ◽  
Link Failure ◽  
Link Failures ◽  
Small Depth ◽  
Internal Link ◽  
Banyan Network ◽  
Minimum Number ◽  
Switch Design ◽  
Banyan Networks

Vertically stacked optical banyan (VSOB) networks are attractive for serving as optical switching systems due to the desirable properties (such as the small depth and self-routing capability) of banyan network structures. Although banyan-type networks result in severe blocking and crosstalk, both these problems can be minimized by using sufficient number of banyan planes in the VSOB network structure. The number of banyan planes is minimum for rearrangeably nonblocking and maximum for strictly nonblocking structure. Both results are available for VSOB networks when there exist no internal link-failures. Since the issue of link-failure is unavoidable, we intend to find the minimum number of planes required to make a VSOB network nonblocking when some links are broken or failed in the structure. This paper presents the approximate number of planes required to make a VSOB networks rearrangeably nonblocking allowing link-failures. We also show an interesting behavior of the  blocking  probability of a faulty VSOB networks that the blocking probability may not  always  increase monotonously with  the  increase  of  link-failures; blocking probability  decreases  for  certain range of  link-failures, and then increases again. We believe that such fluctuating behavior of blocking probability with the increase of link failure probability deserves special attention in switch design.  Keywords: Banyan networks; Blocking probability; Switching networks; Vertical stacking; Link-failures. © 2009 JSR Publications. ISSN: 2070-0237(Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v1i1.1070

Pyrethroids and voltage sensors in sodium channels

2016 ◽  
Author(s):  
Eugenio Eduardo Oliveira
Keyword(s):  
Sodium Channels ◽  
Voltage Sensors
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