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Ramis R, Ballesteros ÓR, Muguruza-Montero A, M-Alicante S, Núñez E, Villarroel Á, Leonardo A, Bergara A. Molecular dynamics simulations of the calmodulin-induced α-helix in the SK2 calcium-gated potassium ion channel. J Biol Chem 2022; 299:102850. [PMID: 36587765 PMCID: PMC9874072 DOI: 10.1016/j.jbc.2022.102850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 12/21/2022] [Accepted: 12/23/2022] [Indexed: 12/30/2022] Open
Abstract
The family of small-conductance Ca2+-activated potassium ion channels (SK channels) is composed of four members (SK1, SK2, SK3, and SK4) involved in neuron-firing regulation. The gating of these channels depends on the intracellular Ca2+ concentration, and their sensitivity to this ion is provided by calmodulin (CaM). This protein binds to a specific region in SK channels known as the calmodulin-binding domain (CaMBD), an event which is essential for their gating. While CaMBDs are typically disordered in the absence of CaM, the SK2 channel subtype displays a small prefolded α-helical region in its CaMBD even if CaM is not present. This small helix is known to turn into a full α-helix upon CaM binding, although the molecular-level details for this conversion are not fully understood yet. In this work, we offer new insights on this physiologically relevant process by means of enhanced sampling, atomistic Hamiltonian replica exchange molecular dynamics simulations, providing a more detailed understanding of CaM binding to this target. Our results show that CaM is necessary for inducing a full α-helix along the SK2 CaMBD through hydrophobic interactions with V426 and L427. However, it is also necessary that W431 does not compete for these interactions; the role of the small prefolded α-helix in the SK2 CaMBD would be to stabilize W431 so that this is the case. In conclusion, our findings provide further insight into a key interaction between CaM and SK channels that is important for channel sensitivity to Ca2+.
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Affiliation(s)
- Rafael Ramis
- Donostia International Physics Center, Donostia, Spain; Departamento de Física, Universidad del País Vasco, UPV/EHU, Leioa, Spain.
| | - Óscar R. Ballesteros
- Departamento de Física, Universidad del País Vasco, UPV/EHU, Leioa, Spain,Centro de Física de Materiales CFM, CSIC-UPV/EHU, Donostia, Spain
| | | | - Sara M-Alicante
- Departamento de Física, Universidad del País Vasco, UPV/EHU, Leioa, Spain,Instituto Biofisika, CSIC-UPV/EHU, Leioa, Spain
| | - Eider Núñez
- Departamento de Física, Universidad del País Vasco, UPV/EHU, Leioa, Spain,Instituto Biofisika, CSIC-UPV/EHU, Leioa, Spain
| | | | - Aritz Leonardo
- Donostia International Physics Center, Donostia, Spain,Departamento de Física, Universidad del País Vasco, UPV/EHU, Leioa, Spain
| | - Aitor Bergara
- Donostia International Physics Center, Donostia, Spain,Departamento de Física, Universidad del País Vasco, UPV/EHU, Leioa, Spain,Centro de Física de Materiales CFM, CSIC-UPV/EHU, Donostia, Spain
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M De la Fuente I, Malaina I, Pérez-Samartín A, Boyano MD, Pérez-Yarza G, Bringas C, Villarroel Á, Fedetz M, Arellano R, Cortes JM, Martínez L. Dynamic properties of calcium-activated chloride currents in Xenopus laevis oocytes. Sci Rep 2017; 7:41791. [PMID: 28198817 PMCID: PMC5304176 DOI: 10.1038/srep41791] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 12/30/2016] [Indexed: 11/18/2022] Open
Abstract
Chloride is the most abundant permeable anion in the cell, and numerous studies in the last two decades highlight the great importance and broad physiological role of chloride currents mediated anion transport. They participate in a multiplicity of key processes, as for instance, the regulation of electrical excitability, apoptosis, cell cycle, epithelial secretion and neuronal excitability. In addition, dysfunction of Cl− channels is involved in a variety of human diseases such as epilepsy, osteoporosis and different cancer types. Historically, chloride channels have been of less interest than the cation channels. In fact, there seems to be practically no quantitative studies of the dynamics of chloride currents. Here, for the first time, we have quantitatively studied experimental calcium-activated chloride fluxes belonging to Xenopus laevis oocytes, and the main results show that the experimental Cl− currents present an informational structure characterized by highly organized data sequences, long-term memory properties and inherent “crossover” dynamics in which persistent correlations arise at short time intervals, while anti-persistent behaviors become dominant in long time intervals. Our work sheds some light on the understanding of the informational properties of ion currents, a key element to elucidate the physiological functional coupling with the integrative dynamics of metabolic processes.
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Affiliation(s)
- Ildefonso M De la Fuente
- Department of Nutrition, CEBAS-CSIC Institute, Espinardo University Campus, Murcia, Spain.,Department of Mathematics, Faculty of Science and Technology, University of the Basque Country, UPV/EHU, Leioa, Spain
| | - Iker Malaina
- Department of Mathematics, Faculty of Science and Technology, University of the Basque Country, UPV/EHU, Leioa, Spain
| | - Alberto Pérez-Samartín
- Department of Neurosciences, Faculty of Medicine and Dentistry, University of the Basque Country, UPV/EHU, Leioa, Spain
| | - María Dolores Boyano
- Department of Cell Biology and Histology, Faculty of Medicine and Dentistry, University of the Basque Country, UPV/EHU, Leioa, Spain
| | - Gorka Pérez-Yarza
- Department of Cell Biology and Histology, Faculty of Medicine and Dentistry, University of the Basque Country, UPV/EHU, Leioa, Spain
| | - Carlos Bringas
- Department of Cell Biology and Histology, Faculty of Medicine and Dentistry, University of the Basque Country, UPV/EHU, Leioa, Spain
| | - Álvaro Villarroel
- Biophysics Unit, CSIC, University of the Basque Country, UPV/EHU, Leioa, Spain
| | - María Fedetz
- Department of Biochemistry and Pharmacology, Institute of Parasitology and Biomedicine "López-Neyra", CSIC, Granada, Spain
| | - Rogelio Arellano
- Laboratory of Cellular Neurophysiology, Neurobiology Institute, UNAM, Querétaro, México
| | - Jesus M Cortes
- Department of Cell Biology and Histology, Faculty of Medicine and Dentistry, University of the Basque Country, UPV/EHU, Leioa, Spain.,BioCruces Health Research Institute, Cruces University Hospital, Barakaldo, Spain.,IKERBASQUE: The Basque Foundation for Science, Bilbao, Spain
| | - Luis Martínez
- Department of Mathematics, Faculty of Science and Technology, University of the Basque Country, UPV/EHU, Leioa, Spain
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Anta B, Martín-Rodríguez C, Gomis-Perez C, Calvo L, López-Benito S, Calderón-García AA, Vicente-García C, Villarroel Á, Arévalo JC. Ubiquitin-specific Protease 36 (USP36) Controls Neuronal Precursor Cell-expressed Developmentally Down-regulated 4-2 (Nedd4-2) Actions over the Neurotrophin Receptor TrkA and Potassium Voltage-gated Channels 7.2/3 (Kv7.2/3). J Biol Chem 2016; 291:19132-45. [PMID: 27445338 DOI: 10.1074/jbc.m116.722637] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Indexed: 11/06/2022] Open
Abstract
Ubiquitination of the TrkA neurotrophin receptor in response to NGF is critical in the regulation of TrkA activation and functions. TrkA is ubiquitinated, among other E3 ubiquitin ligases, by Nedd4-2. To understand mechanistically how TrkA ubiquitination is regulated, we performed a siRNA screening to identify deubiquitinating enzymes and found that USP36 acts as an important regulator of TrkA activation kinetics and ubiquitination. However, USP36 action on TrkA was indirect because it does not deubiquitinate TrkA. Instead, USP36 binds to Nedd4-2 and regulates the association of TrkA and Nedd4-2. In addition, depletion of USP36 increases TrkA·Nedd4-2 complex formation, whereas USP36 expression disrupts the complex, resulting in an enhancement or impairment of Nedd4-2-dependent TrkA ubiquitination, respectively. Moreover, USP36 depletion leads to enhanced total and surface TrkA expression that results in increased NGF-mediated TrkA activation and signaling that augments PC12 cell differentiation. USP36 actions extend beyond TrkA because the presence of USP36 interferes with Nedd4-2-dependent Kv7.2/3 channel regulation. Our results demonstrate that USP36 binds to and regulates the actions of Nedd4-2 over different substrates affecting their expression and functions.
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Affiliation(s)
- Begoña Anta
- From the Departmento de Biología Celular y Patología, Instituto de Neurociencias de Castilla y León, University of Salamanca, Salamanca 37007, Spain, the Institute of Biomedical Research of Salamanca, 47195 Salamanca, Spain, and
| | - Carlos Martín-Rodríguez
- From the Departmento de Biología Celular y Patología, Instituto de Neurociencias de Castilla y León, University of Salamanca, Salamanca 37007, Spain, the Institute of Biomedical Research of Salamanca, 47195 Salamanca, Spain, and
| | - Carolina Gomis-Perez
- the Unidad de Biofísica, Consejo Superior de Investigaciones Científicas, CSIC, UPV/EHU, Universidad del País Vasco, barrio Sarriena s/n, 48940 Leoia, Spain
| | - Laura Calvo
- From the Departmento de Biología Celular y Patología, Instituto de Neurociencias de Castilla y León, University of Salamanca, Salamanca 37007, Spain, the Institute of Biomedical Research of Salamanca, 47195 Salamanca, Spain, and
| | - Saray López-Benito
- From the Departmento de Biología Celular y Patología, Instituto de Neurociencias de Castilla y León, University of Salamanca, Salamanca 37007, Spain, the Institute of Biomedical Research of Salamanca, 47195 Salamanca, Spain, and
| | - Andrés A Calderón-García
- From the Departmento de Biología Celular y Patología, Instituto de Neurociencias de Castilla y León, University of Salamanca, Salamanca 37007, Spain
| | - Cristina Vicente-García
- From the Departmento de Biología Celular y Patología, Instituto de Neurociencias de Castilla y León, University of Salamanca, Salamanca 37007, Spain, the Institute of Biomedical Research of Salamanca, 47195 Salamanca, Spain, and
| | - Álvaro Villarroel
- the Unidad de Biofísica, Consejo Superior de Investigaciones Científicas, CSIC, UPV/EHU, Universidad del País Vasco, barrio Sarriena s/n, 48940 Leoia, Spain
| | - Juan C Arévalo
- From the Departmento de Biología Celular y Patología, Instituto de Neurociencias de Castilla y León, University of Salamanca, Salamanca 37007, Spain, the Institute of Biomedical Research of Salamanca, 47195 Salamanca, Spain, and
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