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Voltage gated potassium channels (KV) are membrane proteins that allow selective flow of K ions in a voltage-dependent manner. These channels play an important role in several excitable cells as neurons, cardiomyocytes, and vascular smooth muscle. Over the last 20 years, it has been shown that omega-3 polyunsaturated fatty acids (PUFAs) enhance or decrease the activity of several cardiac KV channels. PUFAs-dependent modulation of potassium ion channels has been reported to be cardioprotective. However, the precise cellular mechanism underlying the cardiovascular benefits remained unclear in part because new PUFAs targets and signaling pathways continue being discovered. In this review, we will focus on recent data available concerning the following aspects of the K channel modulation by PUFAs: (i) the exact residues involved in PUFAs-K channels interaction; (ii) the structural PUFAs determinants important for their effects on K channels; (iii) the mechanism of the gating modulation of KV channels and, finally, (iv) the PUFAs modulation of a few new targets present in smooth muscle cells (SMC), K1.1, KP, and KATP channels, involved in vascular relaxation.

Our understanding of the role of bottom currents and associated oceanographic processes (e.g, overflows, barotropic tidal currents) including intermittent processes (e.g, vertical eddies, deep sea storms, horizontal vortices, internal waves and tsunamis) is rapidly evolving. Many deep-water processes remain poorly understood due to limited direct observations, but may generate significant depositional and erosional features on both short-and long-term time scales. This paper describes these oceanographic processes and examines their potential role in the sedimentary features around the Iberian margin. The paper explores the implications of the processes studied, given their secondary role relative to other factors such as mass-transport and turbiditic processes. An integrated interpretation of these oceanographic processes requires an understanding of contourites, sea-floor features, their spatial and temporal evolution, and the near-bottom flows that form them. Given their complex, three-dimensional and temporally-variable nature, integration of these processes into sedimentary, oceanographic and climatological frameworks will require a multidisciplinary approach that includes Geology, Physical Oceanography, Paleoceanography and Benthic Biology. This approach will synthesize oceanographic data, seafloor morphology, sediments and seismic images to improve our knowledge of permanent and intermittent processes around Iberia, and evaluate their conceptual and regional role in the sedimentary evolution of the margin. © 2015, Instituto Geologico y Minero de Espana. All rights reserved, El conocimiento del papel de las corrientes de fondo y los procesos oceanográficos asociados (overflows, corrientes de marea barotrópicas, etc), incluyendo procesos intermitentes (eddies, tormentas profundas, ondas internas, tsunamis, etc), está evolucionando rápidamente. Muchos de estos procesos son poco conocidos, en parte debido a que las observaciones directas son limitadas, si bien pueden generar importantes rasgos deposicionales y/o erosivos a escalas temporales de corto o largo periodo. Este artículo describe dichos procesos oceanográficos y examina su influencia en la presencia de rasgos sedimentarios alrededor del margen Ibérico. El trabajo discute las implicaciones de dichos procesos y el papel secundario que juegan en relación a otros factores tales como los procesos de transporte gravitacionales en masa y los turbidíticos. Para un mejor conocimiento de la sedimentación marina profunda, y en concreto de los sistemas contorníticos, se requiere de una interpretación de estos procesos oceanográficos, cuál es su evolución espacial y temporal, cómo afectan a las corrientes de fondo y cómo se ven afectados por la topografía submarina. Sin embargo, dada su complejidad y su variable naturaleza tridimensional y temporal, es necesario que estos procesos se integren en un marco sedimentológico, oceanográfico y climatológico con un enfoque multidisciplinar que incluyan la Geología, la Oceanografía Física, la Paleoceanografía y la Biología bentónica. Esta integración requiere de una mayor compilación de datos oceanográficos, de un mejor conocimiento de la morfología del fondo marino, y de una mejor caracterización de los sedimentos en ambientes profundos. Todo ello permitirá mejorar nuestro conocimiento de los procesos permanentes e intermitentes alrededor de Iberia y evaluar su verdadero efecto en la evolución sedimentaria delos márgenes continentales que le rodean

Altered neuronal calcium homeostasis and early compensatory changes in transcriptional programs are common features of many neurodegenerative pathologies including Alzheimer¿s disease, Down syndrome and Huntington¿s disease. DREAM (Downstream Regulatory Element Antagonist Modulator), also known as calsenilin or KChIP-3 (potassium channel interacting protein-3), is a multifunctional calcium binding protein that controls the expression level and/or the activity of several proteins related to calcium homeostasis, neuronal excitability and neuronal survival. This protein is widely expressed in the brain and, depending on the cell type and physiological conditions, shows multiple subcellular localizations, in the nucleus, cytosol or cell membrane. The interest in DREAM is based on its key role in the regulation of intracellular calcium levels. As a calcium-dependent transcriptional repressor, DREAM is a master regulator of activity-dependent gene expression and controls genes important for calcium homeostasis such as the sodium/calcium exchanger-3 (NCX3), IP3R and L-type calcium channels. As an auxiliary protein in the plasma membrane, DREAM interacts with and regulates the gating of Kv4 potassium channels, L- and T-type voltage-dependent calcium channels and NMDA receptors. These findings suggest that DREAM could be a novel and versatile target for therapeutic intervention in neurodegeneration and that molecules able to bind to DREAM and block its physiological functions could be candidates for drugs to treat neurodegenerative diseases. Moreover, up to now, only two DREAM-binding molecules have been identified. In this communication we report the rational design and the synthesis of novel DREAM-binding molecules and their effects on the modulation of DREAM/protein interactions.

En el presente Trabajo de Fin de Máster, hemos estudiado los efectos electrofisiológicos de los compuestos PC332 y PC342 sobre canales KV4.3 y KV4.3+KChIP3. Para ello hemos transfectado células CHO con el cDNA codificante de KV4.3 y KChIP3 y hemos registrado las corrientes generadas por dichos canales KV4.3 y Kv4.3+KChIP3 utilizando la configuración de célula entera de la técnica de patch-clamp. En este estudio hemos demostrado que: i) PC332 se une de forma selectiva a KChIP3, mientras que PC342 no presenta selectividad por esta subunidad reguladora, inhibiendo de forma similar los canales KV4.3 y KV4.3+KChIP3 y ii) los efectos de PC332 resultaron ser tiempo- y voltaje- dependientes, de forma consistente con la unión del fármaco preferentemente a un estado cerrado-activo.

[Aims]: KCNQ1 and KCNE1 encode Kv7.1 and KCNE1, respectively, the pore-forming and the accessory subunits of the slow delayed rectifier potassium current, IKs. KCNQ1 mutations are associated with long and short QT syndrome. The aim of this study was to characterize the biophysical and cellular phenotype of a KCNQ1 missense mutation, F279I, found in a 23-year-old man with a corrected QT interval (QTc) of 356 ms and a family history of sudden cardiac death. [Methods and Results]: Experiments were performed using perforated patch-clamp, western blot, co-immunoprecipitation, biotinylation, and immunocytochemistry techniques in HEK293, COS7 cells and in cardiomyocytes transfected with WT Kv7.1/KCNE1 or F279I Kv7.1/KCNE1 channels. In the absence of KCNE1, F279I Kv7.1 current exhibited a lesser degree of inactivation than WT Kv7.1. Also, functional analysis of F279I Kv7.1 in the presence of KCNE1 revealed a negative shift in the activation curve and an acceleration of the activation kinetics leading to a gain of function in IKs. The co-assembly between F279I Kv7.1 channels and KCNE1 was markedly decreased compared with WT Kv7.1 channels, as revealed by co-immunoprecipitation and Föster Resonance Energy Transfer experiments. All these effects contribute to the increase of IKs when channels incorporate F279I Kv7.1 subunits, as shown by a computer model simulation of these data that predicts a shortening of the action potential (AP) consistent with the patient phenotype. [Conclusion]: The F279I mutation induces a gain of function of IKs due to an impaired gating modulation of Kv7.1 induced by KCNE1, leading to a shortening of the cardiac AP.

The Kvß1.3 subunit modifies the gating and pharmacology of Kv1.5 channels in a PKC-dependent manner, decreasing channel sensitivity to bupivacaine- and quinidine-mediated blockade. Cardiac Kv1.5 channels associate with receptor for activated C kinase 1 (RACK1), the Kvß1.3 subunit and different PKC isoforms, resulting in the formation of a functional channelosome. The aim of the present study was to investigate the effects of PKC inhibition on bupivacaine and quinidine block of Kv1.5 + Kvß1.3 channels. HEK293 cells were transfected with Kv1.5 + Kvß1.3 channels, and currents were recorded using the whole-cell configuration of the patch-clamp technique. PKC inhibition was achieved by incubating the cells with either calphostin C or bisindolylmaleimide II and the effects of bupivacaine and quinidine were analysed. The voltage-dependent inactivation of Kv1.5 + Kvß1.3 channels and their pharmacological behavior after PKC inhibition with calphostin C were similar to those displayed by Kv1.5 channels alone. Indeed, the IC50 values for bupivacaine were similar in cells whose PKC was inhibited with calphostin C or bisindolylmaleimide II. Similar results were also observed in the presence of quinidine. The finding that the voltage-dependence of inactivation and the pharmacology of Kv1.5 + Kvß1.3 channels after PKC inhibition resembled that observed in Kv1.5 channels suggests that both processes are dependent on PKC-mediated phosphorylation. These results may have clinical relevance in diseases that are characterized by alterations in kinase activity.

Altered neuronal calcium homeostasis and early compensatory changes in transcriptional programs are common features of many neurodegenerative pathologies including Alzheimer's disease, Down syndrome and Huntington's disease. DREAM (Downstream Regulatory Element Antagonist Modulator, also known as calsenilin or KChIP-3 (potassium channel interacting protein-3), is a multifunctional calcium binding protein that controls the expression level and/or the activity of several proteins related to calcium homeostasis, neuronal excitability and neuronal survival. This protein is widely expressed in the brain and, depending on the cell type and physiological conditions, shows multiple subcellular localizations, in the nucleus, cytosol or cell membrane. The interest in DREAM is based on its key role in the regulation of intracellular calcium levels. As a calcium-dependent transcriptional repressor, DREAM is a master regulator of activity-dependent gene expression and controls genes important for calcium homeostasis. As an auxiliary protein in the plasma membrane, DREAM interacts with and regulates the gating of Kv4 potassium channels, L- and T-type voltage-dependent calcium channels and NMDA receptors. These findings suggest that DREAM could be a novel and versatile target for therapeutic intervention in neurodegeneration and that molecules able to bind to DREAM and modulate its physiological functions could be candidates for drugs to treat neurodegenerative diseases. Moreover, up to now, only two DREAMbinding molecules have been identified. In this communication we report the rational design and the synthesis of novel DREAM-binding molecules and their effects on the modulation of DREAM/protein interactions.

DREAM, también denominada calsenilina o KChIP3, es una proteína sensora de calcio que regula diferentes genes tras su unión a los sitios DRE del DNA. Fuera del núcleo, DREAM regula diversas funciones celulares mediante su unión a múltiples proteínas, una de las cuales es el canal Kv4.3. Los canales Kv4.3 generan, tras su unión a diferentes subunidades moduladoras, una corriente rápida y transitoria de salida de potasio. En el corazón, los canales Kv4.3 se unen a las subunidades KChIP2 generando la Ito1, que es una de las principales corrientes repolarizantes cardiacas. En neuronas, se asocian a KChIP1 o KChIP3 y generan la IA, que está implicada en funciones muy especializadas como el aprendizaje, la memoria y el comportamiento. En este trabajo, describimos los efectos electrofisiológicos sobre canales Kv4.3 y Kv4.3+KChIP3 expresados en células CHO, de nuevos compuestos diseñados para unirse a KChIP3 con alta afinidad. PC342 inhibió en mayor grado Kv4.3 que Kv4.3+KChIP3, mientras que PC332 y PC358 produjeron una mayor inhibición de la corriente Kv4.3+KChIP3. El bloqueo de los canales inducido por PC332 y PC358 fue tiempo- y voltaje-dependiente, consistente con una unión preferencial a un estado pre-abierto. Así pues, PC332 y PC358 podrían representar un buen punto de partida para el desarrollo de nuevos fármacos que modulen selectivamente la actividad eléctrica neuronal en diferentes poblaciones de neuronas.

Plasma membrane integrity is essential for cell life. Any major break on it immediately induces the death of the affected cell. Different molecules were described as disrupting this cell structure and thus showing antitumor activity. We have previously defined that elisidepsin (Irvalec®, PM02734) inserts and self-organizes in the plasma membrane of tumor cells, inducing a rapid loss of membrane integrity, cell permeabilization and necrotic death. Here we show that, in sensitive HCT-116 colorectal cells, all these effects are consequence of the interaction of elisidepsin with glycosylceramides in the cell membrane. Of note, an elisidepsin-resistant subline (HCT-116-Irv) presented reduced levels of glycosylceramides and no accumulation of elisidepsin in the plasma membrane. Consequently, drug treatment did not induce the characteristic necrotic cell death. Furthermore, GM95, a mutant derivative from B16 mouse melanoma cells lacking ceramide glucosyltransferase (UGCG) activity and thus the synthesis of glycosylceramides, was also resistant to elisidepsin. Over-expression of UGCG gene in these deficient cells restored glycosylceramides synthesis, rendering them sensitive to elisidepsin, at a similar level than parental B16 cells. These results indicate that glycosylceramides act as membrane targets of elisidepsin, facilitating its insertion in the plasma membrane and the subsequent membrane permeabilization that leads to drug-induced cell death. They also indicate that cell membrane lipids are a plausible target for antineoplastic therapy.

A multiple Contourite Depositional System has been defined in the Plio-Quaternary sedimentary register in the Alboran Sea. This multiple system formed by the Atlantic and the low density and high density Mediterranean Waters, which shaped the margins and basins since the opening of the Gibraltar Strait. Three different (paleo)circulation scenarios are proposed since then: the Atlantic water Flooding;the Pliocene circulation, characterized by immature low and high density Mediterranean waters and a strong countercurrent in the Western Basin; and the Quaternary circulation, characterized by tabular Mediterranean water masses with multiple current dynamics,an increasing influence of density contrasts, and climate shifts causing major vertical and horizontal displacements of their interfaces.

The Quaternary stratigraphic architecture of seamounts and surrounding deposits in the eastern Alboran Sea reveals at least 53 stacked MTDs in the Pollux Bank, Sabinar Bank (Sabinar Platform and Western Sabinar), Maimonides Ridge, and Adra Ridge. These MTDs are grouped into two types based on their size: small-scale MTDs (length <5 km and thickness <18 ms) and large-scale MTDs (length >5 km and thickness >18 ms). The study of these deposits has allowed us to define a close relationship between size (thickness-length) and source area gradients. The frequency of MTD events has varied between 40 and 373 kyr throughout the Quaternary (1.8 Ma to present). Correlation between individual MTDs is difficult but could be done for at least one local MTD event between Sabinar Platform and Western Sabinar (Sabinar Bank); in addition, one regional MTD event has been recognized around all of the studied seamounts. These failure events could have been triggered by tectonically controlled seismicity at both regional and local scale.

Macrophages may tune the immune response toward inflammation or tolerance. The proliferation, activation, and resolution or tolerance of immune cells is mainly modulated by membrane transduction of extracellular signals. Some of these interactions involve changes in transmembrane ion fluxes that, in turn, modulate the network of intracellular signaling. Potassium channels modulate macrophage physiology. Blockade of voltage dependent potassium channels (Kv) by specific antagonists decreases macrophage cytokine production and inhibits proliferation. Therefore, Kv channels have been proposed as anti-inflammatory targets. We studied the effects of 15-epi-lipoxin (e-LXA4), an endogenous eicosanoid released in the presence of aspirin on early signaling and on voltage-dependent potassium (Kv: Kv1.3, Kv1.5) and inward rectifier potassium channels (Kir) in mice bone marrow-derived macrophages (BMDM) and in cultured HEK293 cells. Electrophysiological experiments recordings were performed by the wholecell patch-clamp technique. Treatment of BMDM with e-LXA4 inhibited LPS-dependent activation of NF-kB and IKKb activity and protected against LPS activation-dependent apoptosis. Acute treatment of LPS-stimulated BMDM with e-LXA4 resulted in a decrease of Kv currents, compatible with attenuation of the inflammatory response. More importantly, long-term treatment of LPS-stimulated BMDM with e-LXA4 significantly reverted LPS effects on Kv and Kir currents. These effects were partially mediated via the lipoxin receptor (ALX), since were partially reverted in the presence of a selective ALX receptor antagonist. In the present work, we provide evidence for a new mechanism by which e-LXA4 contributes to inflammation resolution consisting in the reversion of LPS effects on Kv and Kir currents in macrophages. In fact, the lack of effects on Kv and Kir currents recorded in HEK293 cells demonstrated that an intracellular signaling network is required to produce the effect observed in BMDM on

[Objective]: Voltage-dependent K (Kv) channels from the Kv7 family are expressed in blood vessels and contribute to cardiovascular physiology. Although Kv7 channel blockers trigger muscle contractions, Kv7 activators act as vasorelaxants. Kv7.1 and Kv7.5 are expressed in many vessels. Kv7.1 is under intense investigation because Kv7.1 blockers fail to modulate smooth muscle reactivity. In this study, we analyzed whether Kv7.1 and Kv7.5 may form functional heterotetrameric channels increasing the channel diversity in vascular smooth muscles. [Approach and Results]: Kv7.1 and Kv7.5 currents elicited in arterial myocytes, oocyte, and mammalian expression systems suggest the formation of heterotetrameric complexes. Kv7.1/Kv7.5 heteromers, exhibiting different pharmacological characteristics, participate in the arterial tone. Kv7.1/Kv7.5 associations were confirmed by coimmunoprecipitation, fluorescence resonance energy transfer, and fluorescence recovery after photobleaching experiments. Kv7.1/Kv7.5 heterotetramers were highly retained at the endoplasmic reticulum. Studies in HEK-293 cells, heart, brain, and smooth and skeletal muscles demonstrated that the predominant presence of Kv7.5 stimulates release of Kv7.1/Kv7.5 oligomers out of lipid raft microdomains. Electrophysiological studies supported that KCNE1 and KCNE3 regulatory subunits further increased the channel diversity. Finally, the analysis of rat isolated myocytes and human blood vessels demonstrated that Kv7.1 and Kv7.5 exhibited a differential expression, which may lead to channel diversity. [Conclusions]: Kv7.1 and Kv7.5 form heterotetrameric channels increasing the diversity of structures which fine-tune blood vessel reactivity. Because the lipid raft localization of ion channels is crucial for cardiovascular physiology, Kv7.1/Kv7.5 heteromers provide efficient spatial and temporal regulation of smooth muscle function. Our results shed light on the debate about the contribution of Kv7 channels to vasocon

[Backgroun adn Purpose]: The Kv ß1.3 subunit modifies the gating and pharmacology of Kv 1.5 channels in a PKC-dependent manner, decreasing channel sensitivity to bupivacaine- and quinidine-mediated blockade. Cardiac Kv 1.5 channels associate with receptor for activated C kinase 1 (RACK1), the Kv ß1.3 subunit and different PKC isoforms, resulting in the formation of a functional channelosome. The aim of the present study was to investigate the effects of PKC inhibition on bupivacaine and quinidine block of Kv 1.5 + Kv ß1.3 channels. [Experimental Approach]: HEK293 cells were transfected with Kv 1.5 + Kv ß1.3 channels, and currents were recorded using the whole-cell configuration of the patch-clamp technique. PKC inhibition was achieved by incubating the cells with either calphostin C or bisindolylmaleimide II and the effects of bupivacaine and quinidine were analysed. [Key Results]: The voltage-dependent inactivation of Kv 1.5 + Kv ß1.3 channels and their pharmacological behaviour after PKC inhibition with calphostin C were similar to those displayed by Kv 1.5 channels alone. Indeed, the IC50 values for bupivacaine were similar in cells whose PKC was inhibited with calphostin C or bisindolylmaleimide II. Similar results were also observed in the presence of quinidine. [Conclusions and Implications]: The finding that the voltage-dependence of inactivation and the pharmacology of Kv 1.5 + Kv ß1.3 channels after PKC inhibition resembled that observed in Kv 1.5 channels suggests that both processes are dependent on PKC-mediated phosphorylation. These results may have clinical relevance in diseases that are characterized by alterations in kinase activity.