Large-conductance Ca 2+ –voltage-activated K + channels (BK channels) control many key physiological processes, such as neurotransmitter release and muscle contraction. A signature feature of BK is that they have the largest single channel conductance all channels. Here we examine mechanism this large conductance. Comparison sequence to lower-conductance a crystallized bacterial (MthK) revealed ring eight negatively charged glutamate residues at entrance intracellular vestibule. This charge,...

Similar to CNG and HCN channels, EAG ERG channels contain a cyclic nucleotide binding domain (CNBD) in their C terminus. While nucleotides have been shown facilitate opening of effect on is less clear. Here we explored modulation mEAG1 hERG1 with fluorescence electrophysiology. Binding the isolated CNBD was examined two independent fluorescence-based methods: changes tryptophan an analog cAMP, 8-NBD-cAMP. As positive control for used mHCN2 channels. Our results indicated that do not bind low...

The human ether-à-go-go–related gene (hERG) encodes a K + channel crucial for repolarization of the cardiac action potential. EAG-related (ERG) channels contain C-terminal cyclic nucleotide-binding homology domain coupled to pore by C-linker. Here, we report structure C-linker/cyclic mosquito ERG at 2.5-Å resolution. reveals that region expected form pocket is negatively charged and occupied short β-strand, referred as intrinsic ligand, explaining lack direct regulation nucleotides. In hERG...

Severe acute respiratory syndrome coronavirus 2 has been causing the pandemic of disease 2019 (COVID-19) that so far resulted in over 450 million infections and six deaths. This virus uses angiotensin-converting enzyme as a receptor to enter host cells affects various tissues addition lungs. The present study reports placental arteries women who gave birth live full-term newborns while developing COVID-19 during pregnancy exhibit severe vascular wall thickening occlusion lumen. A...

Ether-a-go-go (EAG) channels are key regulators of neuronal excitability and tumorigenesis. EAG contain an N-terminal Per-Arnt-Sim (PAS) domain that can regulate currents from by binding small molecules. The molecular mechanism this regulation is not clear. Using surface plasmon resonance electrophysiology we show a molecule ligand imipramine bind to the PAS EAG1 inhibit via binding. We further used combination dynamics (MD) simulations, electrophysiology, mutagenesis investigate current...

Ether-a-go-go (EAG) potassium selective channels are major regulators of neuronal excitability and cancer progression. EAG contain a Per–Arnt–Sim (PAS) domain in their intracellular N-terminal region. The PAS is structurally similar to the domains non-ion channel proteins, where these frequently function as ligand-binding domains. Despite structural similarity, it not known whether can regulate via ligand binding. Here, using surface plasmon resonance, tryptophan fluorescence, analysis...

Since its discovery in 1951, chlorpromazine (CPZ) has been one of the most widely used antipsychotic medications for treating schizophrenia and other psychiatric disorders. In addition to effect, many studies last several decades have found that CPZ a potent antitumorigenic effect. These shown affects number molecular oncogenic targets through multiple pathways, including regulation cell cycle, cancer growth metastasis, chemo-resistance stemness cells. Here we review on mechanisms CPZ's...

The voltage-gated, K+-selective ether á go-go 1 (EAG1) channel is expressed throughout the brain where it thought to regulate neuronal excitability. Besides its normal physiological role in brain, EAG1 abnormally several cancer cell types and promotes tumor progression. Like all other channels KCNH family, have a large intracellular carboxy-terminal region that shares structural similarity with cyclic nucleotide–binding homology domains (CNBHDs). channels, however, are not regulated by...

The geometry of the inner vestibule BK channels was probed by examining effects different sugars in intracellular solution on single-channel current amplitude (unitary current). Glycerol, glucose, and sucrose decreased unitary through a concentration- size-dependent manner, order > glucose glycerol, with outward currents being reduced more than inward currents. fractional decrease directly related to hydrodynamic volume occupied changes osmolality. For concentrations ≤1 M, i/V plots...

Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are major regulators of synaptic plasticity and rhythmic activity in the heart brain. Opening HCN requires membrane hyperpolarization is further facilitated by intracellular nucleotides (cNMPs). In channels, sensed membrane-spanning voltage sensor domain (VSD), cNMP-dependent gating mediated nucleotide-binding (CNBD) connected to pore-forming S6 transmembrane segment via C-linker. Previous functional analysis has suggested a...

Intracellular Mg2+ and natural polyamines block outward currents in BK channels a highly voltage-dependent manner. Here we investigate the contribution of ring eight negatively charged residues (4 x E321/E324) at entrance to inner vestibule this block. Channels with or without (E321N/E324N) negative charge were expressed oocytes unitary recorded from inside-out patches over range intracellular polyamine concentrations. Removing greatly decreased block, increasing KBap (0 mV) for 48.3 ± 3.0...

Proton block of unitary currents through BK channels was investigated with single-channel recording. Increasing intracellular proton concentration decreased current amplitudes an apparent pKa 5.1 without discrete blocking events, indicating fast block. Unitary recorded at pHi 8.0 and 9.0 had the same amplitudes, that 10−8 M H+ little effect. by recording 7.0, 6.0, 5.0 then reduced 13%, 25%, 53%, respectively, +200 mV. K+i relieved in a manner consistent competitive inhibition action H+i....

Hyperpolarization-activated cyclic nucleotide-modulated (HCN) channels control cardiac and neuronal rhythmicity. HCN contain nucleotide-binding domain (CNBD) in their C-terminal region linked to the pore-forming transmembrane segment with a C-linker. The C-linker couples conformational changes caused by direct binding of nucleotides pore opening. Recently, dinucleotides were shown antagonize effect HCN4 but not HCN2 channels. Based on structural analysis mutational studies it has been...

Cardiovascular complications are seen among human immunodeficiency virus (HIV)-positive individuals, who now survive longer due to successful antiretroviral therapies. Pulmonary arterial hypertension (PAH) is a fatal disease characterized by increased blood pressure in the lung circulation. The prevalence of PAH HIV-positive population dramatically higher than that general population. While HIV-1 Group M Subtype B most prevalent subtype western countries, majority infections eastern Africa...

Background Ether-à-go-go (EAG) channels are expressed throughout the central nervous system and also crucial regulators of cell cycle tumor progression. The large intracellular amino- carboxy- terminal domains EAG1 each share similarity with known ligand binding motifs in other proteins, yet have no regulatory ligands. Methodology/Principal Findings Here we screened a library small biologically relevant molecules against novel two-pronged screen to identify channel regulators. In one arm...

Protein cysteine thiol status is a major determinant of oxidative stress and oxidant signaling. The -SulfoBiotics- Redox State Monitoring Kit provides unique opportunity to investigate protein states. This system adds 15-kDa Protein-SHifter reduced residues, this molecular mass shift can be detected by gel electrophoresis. Even in biological samples, Plus allows the states specific proteins studied using Western blotting. Peroxiredoxin 6 (Prx6) one-cysteine peroxiredoxin that scavenges...

KCNH family of potassium channels is responsible for diverse physiological functions ranging from the regulation neuronal excitability and cardiac contraction to cancer progression. contain a Per-Arn-Sim (PAS) domain in their N-terminal cyclic nucleotide-binding homology (CNBH) C-terminal regions. These intracellular domains shape function are important targets drug development. Here we describe surface plasmon resonance (SPR)-based screening method aimed identifying small molecule binders...