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Calcium channel subunit

Benoîte Bourdin, Emilie Segura, Marie-Philippe Tétreault, Sylvie Lesage, Lucie Parent
Inherited or de novo mutations in cation-selective channels may lead to sudden cardiac death. Alteration in the plasma membrane trafficking of these multi-spanning transmembrane proteins, with or without change in channel gating, is often postulated to contribute significantly in this process. It has thus become critical to develop a method to quantify the change of the relative cell surface expression of cardiac ion channels on a large scale. Herein, a detailed protocol is provided to determine the relative total and cell surface expression of cardiac L-type calcium channels CaV1...
September 28, 2016: Journal of Visualized Experiments: JoVE
Jessica M Meves, Binhai Zheng
In this issue of Neuron, Tedeschi et al. (2016) describe the voltage-gated calcium channel subunit alpha2delta2 as a developmental switch from axon elongation to synapse formation and transmission that doubles as a suppressor of axon regeneration, providing a molecular clue for the synaptic stabilization hypothesis of CNS regeneration failure.
October 19, 2016: Neuron
Rajeev B Tajhya, Xueyou Hu, Mark R Tanner, Redwan Huq, Natee Kongchan, Joel R Neilson, George G Rodney, Frank T Horrigan, Lubov T Timchenko, Christine Beeton
Myoblasts are mononucleated precursors of myofibers; they persist in mature skeletal muscles for growth and regeneration post injury. During myotonic dystrophy type 1 (DM1), a complex autosomal-dominant neuromuscular disease, the differentiation of skeletal myoblasts into functional myotubes is impaired, resulting in muscle wasting and weakness. The mechanisms leading to this altered differentiation are not fully understood. Here, we demonstrate that the calcium- and voltage-dependent potassium channel, KCa1...
October 20, 2016: Cell Death & Disease
A Andrade, J Hope, A Allen, V Yorgan, D Lipscombe, J Q Pan
CACNA1I is a candidate schizophrenia risk gene. It encodes the pore-forming human CaV3.3 α1 subunit, a subtype of voltage-gated calcium channel that contributes to T-type currents. Recently, two de novo missense variations, T797M and R1346H, of hCaV3.3 were identified in individuals with schizophrenia. Here we show that R1346H, but not T797M, is associated with lower hCaV3.3 protein levels, reduced glycosylation, and lower membrane surface levels of hCaV3.3 when expressed in human cell lines compared to wild-type...
October 19, 2016: Scientific Reports
Emmanuel Bourinet, Gerald W Zamponi
Venoms from various predatory species, such as fish hunting mollusks scorpions, snakes and arachnids contain a large spectrum of toxins that include blockers of voltage-gated calcium channels. These peptide blockers act by two principal manners - physical occlusion of the pore and prevention of activation gating. Many of the calcium channel-blocking peptides have evolved to tightly occupy their binding pocket on the principal pore forming subunit of the channel, often rendering block poorly reversible. Moreover, several of the best characterized blocking peptides have developed a high degree of channel subtype selectivity...
October 15, 2016: Neuropharmacology
Zhenzhen Yan, Bin Hu, Zhigang Huang, Ling Zhong, Xiying Guo, Anxi Weng, Feng Xiao, Wenping Zeng, Yan Zhang, Jiuping Ding, Panpan Hou
Large-conductance Ca2+- and voltage-activated potassium (BK) channels are widely expressed in tissues. As a voltage and calcium sensor, BK channels play significant roles in regulating the action potential frequency, neurotransmitter release, and smooth muscle contraction. After associating with the auxiliary β2 subunit, mammalian BK(β2) channels (mouse or human Slo1/β2) exhibit enhanced activation and complete inactivation. However, how the β2 subunit modulates the Drosophila Slo1 channel remains elusive...
2016: PloS One
Michal Behuliak, Michal Bencze, Anna Vavrinova, Ivana Vaneckova, Josef Zicha
OBJECTIVE: Voltage-dependent calcium channels (VDCCs) play an important role in two major abnormalities observed in spontaneously hypertensive rats (SHR) - hyperactivity of sympathetic nervous system (SNS) and enhanced Ca influx to vascular smooth muscle cells (VSMC). α2δ subunit of VDCC, which promotes surface trafficking and modulates the biophysical properties of VDCC, was identified as a critical component of increased L-type VDCC calcium currents in arterial myocytes of SHR. On the other hand, N-type VDCCs control a neurotransmitter release in the peripheral sympathetic nervous system and play an important role in sympathetic hyperactivity in SHR...
September 2016: Journal of Hypertension
Zhenyu Hu, Jiong-Wei Wang, Dejie Yu, Jia Lin Soon, Dominique P V de Kleijn, Roger Foo, Ping Liao, Henry M Colecraft, Tuck Wah Soong
Decreased expression and activity of CaV1.2 calcium channels has been reported in pressure overload-induced cardiac hypertrophy and heart failure. However, the underlying mechanisms remain unknown. Here we identified in rodents a splice variant of CaV1.2 channel, named CaV1.2e21+22, that contained the pair of mutually exclusive exons 21 and 22. This variant was highly expressed in neonatal hearts. The abundance of this variant was gradually increased by 12.5-folds within 14 days of transverse aortic banding that induced cardiac hypertrophy in adult mouse hearts and was also elevated in left ventricles from patients with dilated cardiomyopathy...
October 12, 2016: Scientific Reports
Anna Kicinska, Bartlomiej Augustynek, Bogusz Kulawiak, Wieslawa Jarmuszkiewicz, Adam Szewczyk, Piotr Bednarczyk
Potassium channels have been found in the inner mitochondrial membrane of various cells. These channels regulate the mitochondrial membrane potential, respiration and the production of reactive oxygen species. In this study, we identified the activity of a large-conductance Ca(2+)-regulated potassium channel (mitoBKCa channel) in mitoplasts isolated from a primary human dermal fibroblast cell line. A potassium selective current was recorded with a mean conductance of 280 ± 2 pS in a symmetrical 150 mM KCl solution...
October 11, 2016: Biochemical Journal
Birol Cabukusta, Jan A Köhlen, Christian P Richter, Changjiang You, Joost C M Holthuis
Single-molecule photobleaching has emerged as a powerful non-invasive approach to extract the stoichiometry of multimeric membrane proteins in their native cellular environment. However, this method has mainly been used to determine the subunit composition of ion channels and receptors at the plasma membrane. In here we applied single-molecule photobleaching to analyse the oligomeric state of an ER-resident candidate ceramide sensor protein, SMSr/SAMD8. Co-immunoprecipitation and chemical crosslinking studies previously revealed that the N-terminal sterile alpha motif or SAM domain of SMSr drives self-assembly of the protein into oligomers and that SMSr oligomerization is promoted by curcumin, a drug known to perturb ER ceramide and calcium homeostasis...
October 10, 2016: Journal of Biological Chemistry
Sean D Boothe, Jackson D Myers, Seokwon Pok, Junping Sun, Yutao Xi, Raymond M Nieto, Jie Cheng, Jeffrey G Jacot
The stiffness of myocardial tissue changes significantly at birth and during neonatal development, concurrent with significant changes in contractile and electrical maturation of cardiomyocytes. Previous studies by our group have shown that cardiomyocytes generate maximum contractile force when cultured on a substrate with a stiffness approximating native cardiac tissue. However, effects of substrate stiffness on the electrophysiology and ion currents in cardiomyocytes have not been fully characterized. In this study, neonatal rat ventricular myocytes were cultured on the surface of flat polyacrylamide hydrogels with elastic moduli ranging from 1 to 25 kPa...
October 8, 2016: Cell Biochemistry and Biophysics
Andrea Tedeschi, Sebastian Dupraz, Claudia J Laskowski, Jia Xue, Thomas Ulas, Marc Beyer, Joachim L Schultze, Frank Bradke
Injuries to the adult CNS often result in permanent disabilities because neurons lose the ability to regenerate their axon during development. Here, whole transcriptome sequencing and bioinformatics analysis followed by gain- and loss-of-function experiments identified Cacna2d2, the gene encoding the Alpha2delta2 subunit of voltage-gated calcium channels (VGCCs), as a developmental switch that limits axon growth and regeneration. Cacna2d2 gene deletion or silencing promoted axon growth in vitro. In vivo, Alpha2delta2 pharmacological blockade through Pregabalin (PGB) administration enhanced axon regeneration in adult mice after spinal cord injury (SCI)...
September 27, 2016: Neuron
Sabine Nafzger, Jean-Sebastien Rougier
AIM: The L-type voltage-gated calcium channel Cav1.2 mediates the calcium influx into cells upon membrane depolarization. The list of cardiopathies associated to Cav1.2 dysfunctions highlights the importance of this channel in cardiac physiology. Calcium/calmodulin-dependent serine protein kinase (CASK), expressed in cardiac cells, has been identified as a regulator of Cav2.2 channels in neurons, but no experiments have been performed to investigate its role in Cav1.2 regulation. METHODS AND RESULTS: Full length or the distal C-terminal truncated of the pore-forming Cav1...
October 5, 2016: Cell Calcium
Sukanya Lodh, Junji Yano, Megan S Valentine, Judith L Van Houten
Paramecium cells swim by beating their cilia, and make turns by transiently reversing their power stroke. Reversal is caused by Ca(2+) entering the cilium through voltage-gated Ca(2+) (CaV) channels that are found exclusively in the cilia. As ciliary Ca(2+) levels return to normal, the cell pivots and swims forward in a new direction. Thus, the activation of the CaV channels causes cells to make a turn in their swimming paths. For 45 years, the physiological characteristics of the Paramecium ciliary CaV channels have been known, but the proteins were not identified until recently, when the P...
October 1, 2016: Journal of Experimental Biology
A F Dulhunty, L Wei-LaPierre, M G Casarotto, N A Beard
The core skeletal muscle ryanodine receptor (RyR1) calcium release complex extends through three compartments of the muscle fibre, linking the extracellular environment through the cytoplasmic junctional gap to the lumen of the internal sarcoplasmic reticulum (SR) calcium store. The protein complex is essential for skeletal excitation-contraction (EC-) coupling and skeletal muscle function. Its importance is highlighted by perinatal death if any one of the EC-coupling components are missing and by myopathies associated with mutation of any of the proteins...
October 1, 2016: Clinical and Experimental Pharmacology & Physiology
Chen Zhang
The present diagnostic classification of mental illnesses is primarily based on symptomatology. A recent cross-disorder genome-wide association study revealed that there were genetic similarities between multiple clinically defined diagnoses (including schizophrenia, bipolar disorder, depression, attention deficit hyperactivity disorder, and autism spectrum disorder) on regions of chromosomes 3p21 and 10q24 and single-nucleotide polymorphisms (SNPs) within two L-type voltage-gated calcium channel subunits of CACNA1C and CACNB2...
February 25, 2016: Shanghai Archives of Psychiatry
Jennifer J DuPont, Amy McCurley, Ana P Davel, Joseph McCarthy, Shawn B Bender, Kwangseok Hong, Yan Yang, Jeung-Ki Yoo, Mark Aronovitz, Wendy E Baur, Demetra D Christou, Michael A Hill, Iris Z Jaffe
Hypertension is nearly universal yet poorly controlled in the elderly despite proven benefits of intensive treatment. Mice lacking mineralocorticoid receptors in smooth muscle cells (SMC-MR-KO) are protected from rising blood pressure (BP) with aging, despite normal renal function. Vasoconstriction is attenuated in aged SMC-MR-KO mice, thus they were used to explore vascular mechanisms that may contribute to hypertension with aging. MicroRNA (miR) profiling identified miR-155 as the most down-regulated miR with vascular aging in MR-intact but not SMC-MR-KO mice...
September 8, 2016: JCI Insight
Hye-Jin Boo, Hye-Young Min, Hyun-Ji Jang, Hye Jeong Yun, John Kendal Smith, Quanri Jin, Hyo-Jong Lee, Diane Liu, Hee-Seok Kweon, Carmen Behrens, J Jack Lee, Ignacio I Wistuba, Euni Lee, Waun Ki Hong, Ho-Young Lee
Nicotinic acetylcholine receptors (nAChRs) binding to the tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) induces Ca(2+) signalling, a mechanism that is implicated in various human cancers. In this study, we investigated the role of NNK-mediated Ca(2+) signalling in lung cancer formation. We show significant overexpression of insulin-like growth factors (IGFs) in association with IGF-1R activation in human preneoplastic lung lesions in smokers. NNK induces voltage-dependent calcium channel (VDCC)-intervened calcium influx in airway epithelial cells, resulting in a rapid IGF2 secretion via the regulated pathway and thus IGF-1R activation...
2016: Nature Communications
Chunmei Zhang, Ninghui Zhao, Yao Chen, Donghua Zhang, Jinyuan Yan, Wei Zou, Keqin Zhang, Xiaowei Huang
The nematode Caenorhabditis elegans exhibits behavioral responses to a wide range of odorants associated with food and pathogens. A previous study described a Trojan Horse like strategy of pathogenesis whereby the bacterium Bacillus subtilis emits the volatile organic compound 2-heptanone to trap C. elegans for successful infection. Here, we further explored the receptor for 2-heptanone as well as the pathway involved in signal transduction in C. elegans. Our experiments showed that 2-heptanone sensing depended on the function of AWC neurons and a GPCR encoded by str-2...
September 22, 2016: Journal of Biological Chemistry
James B Fields, Karin L Németh-Cahalan, J Alfredo Freites, Irene Vorontsova, James E Hall, Douglas J Tobias
Aquaporin 0 (AQP0), the major intrinsic protein of the eye lens, plays a vital role in maintaining lens clarity by facilitating the transport of water across lens fiber cell membranes. AQP0 reduces its osmotic water permeability constant (Pf) in response to increases in the external calcium concentration, an effect that is mediated by an interaction with the calcium-binding messenger protein, calmodulin (CaM), and phosphorylation of the CaM binding site abolishes calcium sensitivity. Despite recent structural characterization of the AQP0-CaM complex, the mechanism by which CaM modulates AQP0 remains poorly understood...
September 22, 2016: Journal of Biological Chemistry
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