• Klíčová slova
• Pain, T-type channel, calcium channel, glycosylation, phosphorylation, post-translational modifications, sumoylation, ubiquitinylation,
• MeSH
• biologické modely MeSH
• lidé MeSH
• neuralgie metabolismus   MeSH
• spinální ganglia metabolismus   MeSH
• vápníkové kanály - typ T metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• vápníkové kanály - typ T MeSH

Low-voltage-activated T-type calcium channels are important contributors to nervous system function. Post-translational modification of these channels has emerged as an important mechanism to control channel activity. Previous studies have documented the importance of asparagine (N)-linked glycosylation and identified several asparagine residues within the canonical consensus sequence N-X-S/T that is essential for the expression and function of Cav3.2 channels. Here, we explored the functional role of non-canonical N-glycosylation motifs in the conformation N-X-C based on site directed mutagenesis. Using a combination of electrophysiological recordings and surface biotinylation assays, we show that asparagines N345 and N1780 located in the motifs NVC and NPC, respectively, are essential for the expression of the human Cav3.2 channel in the plasma membrane. Therefore, these newly identified asparagine residues within non-canonical motifs add to those previously reported in canonical sites and suggest that N-glycosylation of Cav3.2 may also occur at non-canonical motifs to control expression of the channel in the plasma membrane. It is also the first study to report the functional importance of non-canonical N-glycosylation motifs in an ion channel.

• Klíčová slova
• Asparagine-linked glycosylation, Calcium channel, N-glycosylation, Non-canonical glycosylation, T-type channel, Trafficking, cav3.2 Channel,
• MeSH
• aminokyselinové motivy MeSH
• asparagin metabolismus   MeSH
• glykosylace MeSH
• lidé MeSH
• vápníkové kanály - typ T chemie   metabolismus   MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• asparagin MeSH
• CACNA1H protein, human MeSH Prohlížeč
• vápníkové kanály - typ T MeSH

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by the progressive loss of cortical, brain stem and spinal motor neurons that leads to muscle weakness and death. A previous study implicated CACNA1H encoding for Cav3.2 calcium channels as a susceptibility gene in ALS. In the present study, two heterozygous CACNA1H variants were identified by whole genome sequencing in a small cohort of ALS patients. These variants were functionally characterized using patch clamp electrophysiology, biochemistry assays, and molecular modeling. A previously unreported c.454GTAC > G variant produced an inframe deletion of a highly conserved isoleucine residue in Cav3.2 (p.ΔI153) and caused a complete loss-of-function of the channel, with an additional dominant-negative effect on the wild-type channel when expressed in trans. In contrast, the c.3629C > T variant caused a missense substitution of a proline with a leucine (p.P1210L) and produced a comparatively mild alteration of Cav3.2 channel activity. The newly identified ΔI153 variant is the first to be reported to cause a complete loss of Cav3.2 channel function. These findings add to the notion that loss-of-function of Cav3.2 channels associated with rare CACNA1H variants may be risk factors in the complex etiology of ALS.

• Klíčová slova
• ALS, Amyotrophic lateral sclerosis, Biophysics, CACNA1H, Calcium channel, Cav3.2 channel, Motor neuron disease, Mutation, T-type channel,
• MeSH
• amyotrofická laterální skleróza * genetika   MeSH
• dominantní geny MeSH
• genetická predispozice k nemoci * MeSH
• genetické asociační studie * MeSH
• heterozygot MeSH
• krysa rodu Rattus MeSH
• lidé MeSH
• mutace * genetika   MeSH
• sekvence aminokyselin MeSH
• sekvenování celého genomu MeSH
• strukturní homologie proteinů MeSH
• vápníkové kanály - typ T * chemie   genetika   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• lidé MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• CACNA1H protein, human MeSH Prohlížeč
• vápníkové kanály - typ T * MeSH

T-type channels are low-voltage-activated calcium channels that contribute to a variety of cellular and physiological functions, including neuronal excitability, hormone and neurotransmitter release as well as developmental aspects. Several human conditions including epilepsy, autism spectrum disorders, schizophrenia, motor neuron disorders and aldosteronism have been traced to variations in genes encoding T-type channels. In this short review, we present the genetics of T-type channels with an emphasis on structure-function relationships and associated channelopathies.

• Klíčová slova
• aldosteronism, amyotrophic lateral sclerosis, autism spectrum disorders, calcium channels, cav3 channels, channelopathies, epilepsy, mutation, schizophrenia, t-type channels,
• MeSH
• kanálopatie genetika   metabolismus   MeSH
• lidé MeSH
• mutace MeSH
• vápníkové kanály genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• vápníkové kanály MeSH

Low-voltage-activated T-type calcium channels are essential contributors to the functioning of thalamocortical neurons by supporting burst-firing mode of action potentials. Enhanced T-type calcium conductance has been reported in the Genetic Absence Epilepsy Rat from Strasbourg (GAERS) and proposed to be causally related to the overall development of absence seizure activity. Here, we show that calnexin, an endoplasmic reticulum integral membrane protein, interacts with the III-IV linker region of the Cav3.2 channel to modulate the sorting of the channel to the cell surface. We demonstrate that the GAERS missense mutation located in the Cav3.2 III-IV linker alters the Cav3.2/calnexin interaction, resulting in an increased surface expression of the channel and a concomitant elevation in calcium influx. Our study reveals a novel mechanism that controls the expression of T-type channels, and provides a molecular explanation for the enhancement of T-type calcium conductance in GAERS.

• MeSH
• absentní epilepsie genetika   MeSH
• kalnexin metabolismus   MeSH
• krysa rodu Rattus MeSH
• missense mutace * MeSH
• modely nemocí na zvířatech MeSH
• mutantní proteiny genetika   metabolismus   MeSH
• transport proteinů MeSH
• vápníkové kanály - typ T genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• Cacna1h protein, rat MeSH Prohlížeč
• kalnexin MeSH
• mutantní proteiny MeSH
• vápníkové kanály - typ T MeSH

Neuronal voltage-gated calcium channels (VGCCs) serve complex yet essential physiological functions via their pivotal role in translating electrical signals into intracellular calcium elevations and associated downstream signalling pathways. There are a number of regulatory mechanisms to ensure a dynamic control of the number of channels embedded in the plasma membrane, whereas alteration of the surface expression of VGCCs has been linked to various disease conditions. Here, we provide an overview of the mechanisms that control the trafficking of VGCCs to and from the plasma membrane, and discuss their implication in pathophysiological conditions and their potential as therapeutic targets.

• Klíčová slova
• Stac adaptor proteins, ancillary subunit, calcium channels, glycosylation, trafficking, ubiquitination, voltage-gated calcium channels,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

T-type calcium channels are key contributors to neuronal physiology where they shape electrical activity of nerve cells and contribute to the release of neurotransmitters. Enhanced T-type channel expression has been causally linked to a number of pathological conditions including peripheral painful diabetic neuropathy. Recently, it was demonstrated that asparagine-linked glycosylation not only plays an essential role in regulating cell surface expression of Cav3.2 channels, but may also support glucose-dependent potentiation of T-type currents. However, the underlying mechanisms by which N-glycosylation and glucose levels modulate the expression of T-type channels remain elusive. In the present study, we show that site-specific N-glycosylation of Cav3.2 is essential to stabilize expression of the channel at the plasma membrane. In contrast, elevated external glucose concentration appears to potentiate intracellular forward trafficking of the channel to the cell surface, resulting in an increased steady-state expression of the channel protein at the plasma membrane. Collectively, our study indicates that glucose and N-glycosylation act in concert to control the expression of Cav3.2 channels, and that alteration of these mechanisms may contribute to the altered expression of T-type channels in pathological conditions.

• Klíčová slova
• Calcium channel, Cav3.2, Glucose, N-glycosylation, T-type channel, Trafficking,
• MeSH
• asparagin metabolismus   MeSH
• buněčná membrána metabolismus   MeSH
• glukosa farmakologie   MeSH
• glykosylace MeSH
• HEK293 buňky MeSH
• lidé MeSH
• posttranslační úpravy proteinů * MeSH
• transport proteinů účinky léků   MeSH
• vápníkové kanály - typ T genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• asparagin MeSH
• glukosa MeSH
• vápníkové kanály - typ T MeSH

Low-voltage-activated T-type calcium channels are essential contributors to neuronal physiology where they play complex yet fundamentally important roles in shaping intrinsic excitability of nerve cells and neurotransmission. Aberrant neuronal excitability caused by alteration of T-type channel expression has been linked to a number of neuronal disorders including epilepsy, sleep disturbance, autism, and painful chronic neuropathy. Hence, there is increased interest in identifying the cellular mechanisms and actors that underlie the trafficking of T-type channels in normal and pathological conditions. In the present study, we assessed the ability of Stac adaptor proteins to associate with and modulate surface expression of T-type channels. We report the existence of a Cav3.2/Stac1 molecular complex that relies on the binding of Stac1 to the amino-terminal region of the channel. This interaction potently modulates expression of the channel protein at the cell surface resulting in an increased T-type conductance. Altogether, our data establish Stac1 as an important modulator of T-type channel expression and provide new insights into the molecular mechanisms underlying the trafficking of T-type channels to the plasma membrane.

• Klíčová slova
• Cav3.2 channel, Stac adaptor protein, T-type calcium channel, trafficking,
• MeSH
• buněčná membrána metabolismus   MeSH
• HEK293 buňky MeSH
• lidé MeSH
• proteiny nervové tkáně metabolismus   fyziologie   MeSH
• vápníkové kanály - typ T metabolismus   fyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• CACNA1H protein, human MeSH Prohlížeč
• proteiny nervové tkáně MeSH
• vápníkové kanály - typ T MeSH