Voltage‐dependent conformational changes of Kv1.3 channels activate cell proliferation

2020 ◽  
Author(s):  
Pilar Cidad ◽  
Esperanza Alonso ◽  
Marycarmen Arévalo‐Martínez ◽  
Enrique Calvo ◽  
Miguel A. Fuente ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Conformational Changes ◽  
Voltage Dependent ◽  
Kv1.3 Channels ◽  
Activate Cell

scholarly journals Voltage-Dependent Accessibility of Phosphorylation Sites at the Carboxy-Terminal Domain of Kv1.3 Channels Determines Kv1.3-Induced Cell Proliferation

2016 ◽  
Vol 110 (3) ◽  
pp. 526a-527a
Author(s):  
Teresa Pérez-García ◽  
Pilar Cidad ◽  
Laura Jiménez-Perez ◽  
Ines Alvarez-Miguel ◽  
Alba Santos-Hipolito ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Phosphorylation Sites ◽  
Terminal Domain ◽  
Carboxy Terminal Domain ◽  
Voltage Dependent ◽  
Kv1.3 Channels ◽  
Carboxy Terminal

scholarly journals Voltage-Dependent Conformational Changes of KV1.3 Potassium Channels are an Essential Element for KV1.3-induced cell proliferation

2018 ◽  
Vol 114 (3) ◽  
pp. 378a
Author(s):  
M. Teresa Pérez-García ◽  
Pilar Cidad ◽  
Esperanza Alonso ◽  
Pablo Fernández-Velasco ◽  
Miguel A. de la Fuente ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Potassium Channels ◽  
Conformational Changes ◽  
Essential Element ◽  
Voltage Dependent

scholarly journals Structure–Function Relations of the First and Fourth Predicted Extracellular Linkers of the Type IIa Na+/Pi Cotransporter

2004 ◽  
Vol 124 (5) ◽  
pp. 475-488 ◽  
Author(s):  
Colin Ehnes ◽  
Ian C. Forster ◽  
Katja Kohler ◽  
Andrea Bacconi ◽  
Gerti Stange ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Reaction Rates ◽  
Transport Pathway ◽  
Extracellular Medium ◽  
Voltage Range ◽  
Substituted Cysteine Accessibility ◽  
Voltage Dependent ◽  
Opposite Behavior ◽  
Rate Limiting ◽  
Kinetics Of

The putative first intracellular and third extracellular linkers are known to play important roles in defining the transport properties of the type IIa Na+-coupled phosphate cotransporter (Kohler, K., I.C. Forster, G. Stange, J. Biber, and H. Murer. 2002b. J. Gen. Physiol. 120:693–705). To investigate whether other stretches that link predicted transmembrane domains are also involved, the substituted cysteine accessibility method (SCAM) was applied to sites in the predicted first and fourth extracellular linkers (ECL-1 and ECL-4). Mutants based on the wild-type (WT) backbone, with substituted novel cysteines, were expressed in Xenopus oocytes, and their function was assayed by isotope uptake and electrophysiology. Functionally important sites were identified in both linkers by exposing cells to membrane permeant and impermeant methanethiosulfonate (MTS) reagents. The cysteine modification reaction rates for sites in ECL-1 were faster than those in ECL-4, which suggested that the latter were less accessible from the extracellular medium. Generally, a finite cotransport activity remained at the end of the modification reaction. The change in activity was due to altered voltage-dependent kinetics of the Pi-dependent current. For example, cys substitution at Gly-134 in ECL-1 resulted in rate-limiting, voltage-independent cotransport activity for V ≤ −80 mV, whereas the WT exhibited a linear voltage dependency. After cys modification, this mutant displayed a supralinear voltage dependency in the same voltage range. The opposite behavior was documented for cys substitution at Met-533 in ECL-4. Modification of cysteines at two other sites in ECL-1 (Ile-136 and Phe-137) also resulted in supralinear voltage dependencies for hyperpolarizing potentials. Taken together, these findings suggest that ECL-1 and ECL-4 may not directly form part of the transport pathway, but specific sites in these linkers can interact directly or indirectly with parts of NaPi-IIa that undergo voltage-dependent conformational changes and thereby influence the voltage dependency of cotransport.

scholarly journals Interfacial gating triad is crucial for electromechanical transduction in voltage-activated potassium channels

2014 ◽  
Vol 144 (5) ◽  
pp. 457-467 ◽  
Author(s):  
Sandipan Chowdhury ◽  
Benjamin M. Haehnel ◽  
Baron Chanda
Keyword(s):  
Potassium Channels ◽  
Conformational Changes ◽  
Electromechanical Coupling ◽  
Structural Integrity ◽  
Voltage Sensor ◽  
Amino Acid Residues ◽  
Kv Channel ◽  
Electromechanical Transduction ◽  
Voltage Dependent ◽  
Graph Theoretical Approach

Voltage-dependent potassium channels play a crucial role in electrical excitability and cellular signaling by regulating potassium ion flux across membranes. Movement of charged residues in the voltage-sensing domain leads to a series of conformational changes that culminate in channel opening in response to changes in membrane potential. However, the molecular machinery that relays these conformational changes from voltage sensor to the pore is not well understood. Here we use generalized interaction-energy analysis (GIA) to estimate the strength of site-specific interactions between amino acid residues putatively involved in the electromechanical coupling of the voltage sensor and pore in the outwardly rectifying KV channel. We identified candidate interactors at the interface between the S4–S5 linker and the pore domain using a structure-guided graph theoretical approach that revealed clusters of conserved and closely packed residues. One such cluster, located at the intracellular intersubunit interface, comprises three residues (arginine 394, glutamate 395, and tyrosine 485) that interact with each other. The calculated interaction energies were 3–5 kcal, which is especially notable given that the net free-energy change during activation of the Shaker KV channel is ∼14 kcal. We find that this triad is delicately maintained by balance of interactions that are responsible for structural integrity of the intersubunit interface while maintaining sufficient flexibility at a critical gating hinge for optimal transmission of force to the pore gate.

scholarly journals Classification of a frameshift/extended and a stop mutation in WT1 as gain-of-function mutations that activate cell cycle genes and promote Wilms tumour cell proliferation

2014 ◽  
Vol 23 (15) ◽  
pp. 3958-3974 ◽  
Author(s):  
Maike Busch ◽  
Heinrich Schwindt ◽  
Artur Brandt ◽  
Manfred Beier ◽  
Nicole Görldt ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Tumour Cell ◽  
Wilms Tumour ◽  
Gain Of Function ◽  
Cell Cycle Genes ◽  
Stop Mutation ◽  
Tumour Cell Proliferation ◽  
Activate Cell

scholarly journals Voltage Dependent Conformational Changes of the Na+/K+-ATPase Revealed by Site Directed Fluorometry

2015 ◽  
Vol 108 (2) ◽  
pp. 144a
Author(s):  
Jorge E. Sánchez-Rodríguez ◽  
Pablo Miranda-Fernández ◽  
Miguel Holmgren ◽  
Francisco Bezanilla
Keyword(s):  
Conformational Changes ◽  
Voltage Dependent

scholarly journals Structure of the human TRPM4 ion channel in a lipid nanodisc

Science ◽  
2017 ◽  
Vol 359 (6372) ◽  
pp. 228-232 ◽  
Author(s):  
Henriette E. Autzen ◽  
Alexander G. Myasnikov ◽  
Melody G. Campbell ◽  
Daniel Asarnow ◽  
David Julius ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Calcium Binding ◽  
Transient Receptor Potential ◽  
Trp Channels ◽  
Receptor Potential ◽  
Dependent Manner ◽  
Calcium Binding Site ◽  
Voltage Dependent ◽  
Transient Receptor ◽  
Lipid Nanodiscs

Transient receptor potential (TRP) melastatin 4 (TRPM4) is a widely expressed cation channel associated with a variety of cardiovascular disorders. TRPM4 is activated by increased intracellular calcium in a voltage-dependent manner but, unlike many other TRP channels, is permeable to monovalent cations only. Here we present two structures of full-length human TRPM4 embedded in lipid nanodiscs at ~3-angstrom resolution, as determined by single-particle cryo–electron microscopy. These structures, with and without calcium bound, reveal a general architecture for this major subfamily of TRP channels and a well-defined calcium-binding site within the intracellular side of the S1-S4 domain. The structures correspond to two distinct closed states. Calcium binding induces conformational changes that likely prime the channel for voltage-dependent opening.

scholarly journals Characterizing Voltage-Dependent Conformational Changes in the ShakerK+ Channel with Fluorescence

Neuron ◽  
1997 ◽  
Vol 19 (5) ◽  
pp. 1127-1140 ◽  
Author(s):  
Albert Cha ◽  
Francisco Bezanilla
Keyword(s):  
Conformational Changes ◽  
Voltage Dependent

scholarly journals A new mechanism of voltage-dependent gating exposed by KV10.1 channels interrupted between voltage sensor and pore

2017 ◽  
Vol 149 (5) ◽  
pp. 577-593 ◽  
Author(s):  
Adam P. Tomczak ◽  
Jorge Fernández-Trillo ◽  
Shashank Bharill ◽  
Ferenc Papp ◽  
Gyorgy Panyi ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Voltage Sensor ◽  
Ion Flow ◽  
Gating Model ◽  
Cryo Electron Microscopy ◽  
Channel Gate ◽  
Voltage Dependent ◽  
Voltage Gated Ion Channels ◽  
Voltage Sensing Domain ◽  
Pore Domain

Voltage-gated ion channels couple transmembrane potential changes to ion flow. Conformational changes in the voltage-sensing domain (VSD) of the channel are thought to be transmitted to the pore domain (PD) through an α-helical linker between them (S4–S5 linker). However, our recent work on channels disrupted in the S4–S5 linker has challenged this interpretation for the KCNH family. Furthermore, a recent single-particle cryo-electron microscopy structure of KV10.1 revealed that the S4–S5 linker is a short loop in this KCNH family member, confirming the need for an alternative gating model. Here we use “split” channels made by expression of VSD and PD as separate fragments to investigate the mechanism of gating in KV10.1. We find that disruption of the covalent connection within the S4 helix compromises the ability of channels to close at negative voltage, whereas disconnecting the S4–S5 linker from S5 slows down activation and deactivation kinetics. Surprisingly, voltage-clamp fluorometry and MTS accessibility assays show that the motion of the S4 voltage sensor is virtually unaffected when VSD and PD are not covalently bound. Finally, experiments using constitutively open PD mutants suggest that the presence of the VSD is structurally important for the conducting conformation of the pore. Collectively, our observations offer partial support to the gating model that assumes that an inward motion of the C-terminal S4 helix, rather than the S4–S5 linker, closes the channel gate, while also suggesting that control of the pore by the voltage sensor involves more than one mechanism.

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