A5067692998- Ion channel regulation and function
- Cardiac electrophysiology and arrhythmias
- Neuroscience and Neuropharmacology Research
- Mitochondrial Function and Pathology
- ATP Synthase and ATPases Research
- Nicotinic Acetylcholine Receptors Study
- Neuroscience and Neural Engineering
- Advanced Fluorescence Microscopy Techniques
- Cardiac Ischemia and Reperfusion
- Fuel Cells and Related Materials
- bioluminescence and chemiluminescence research
- Receptor Mechanisms and Signaling
- Reproductive Biology and Fertility
- Venomous Animal Envenomation and Studies
- Genetics, Aging, and Longevity in Model Organisms
- Phosphodiesterase function and regulation
- Cardiomyopathy and Myosin Studies
- Electrochemical Analysis and Applications
- Protein Kinase Regulation and GTPase Signaling
- Protein Structure and Dynamics
- Calcium signaling and nucleotide metabolism
- Attention Deficit Hyperactivity Disorder
- Sphingolipid Metabolism and Signaling
- Microbial Inactivation Methods
- Caveolin-1 and cellular processes
National Institute on Aging
2009-2022
National Institutes of Health
2006-2021
National Institute on Drug Abuse
2018
Johns Hopkins University
2018
Johns Hopkins Medicine
2018
University of Baltimore
2012
Institute on Aging
2012
Icahn School of Medicine at Mount Sinai
1994-2001
New York University
2001
Institute of Molecular Biology and Biophysics
2000
Abstract We demonstrated that ATP synthase serves the functions of a primary mitochondrial K+ “uniporter,” i.e., way for to enter mitochondria. This entry is proportional synthesis, regulating matrix volume and energy supply-vs-demand matching. show can be upregulated by endogenous survival-related proteins via IF1. identified conserved BH3-like domain IF1 which overlaps its “minimal inhibitory domain” binds β-subunit F1. Bcl-xL Mcl-1 possess BH3-binding-groove engage exert effects,...
Abstract ATP synthase (F1Fo) synthesizes daily our body's weight in ATP, whose production-rate can be transiently increased several-fold to meet changes energy utilization. Using purified mammalian F1Fo-reconstituted proteoliposomes and isolated mitochondria, we show F1Fo utilize both ΔΨm-driven H+- K+-transport synthesize under physiological pH = 7.2 K+ 140 mEq/L conditions. Purely K+-driven synthesis from single molecules measured by bioluminescence photon detection could directly...
Ceramide, a product of sphingomyelin turnover, is lipid second messenger that mediates diverse signaling pathways, including those leading to cell cycle arrest and differentiation. The mechanism(s) by which ceramide signals downstream events have not been fully elucidated. Here we show that, in Xenopus laevis oocytes, ceramide-induced maturation associated with the release intracellular calcium stores. Ceramide caused dose-dependent elevation inositol 1,4,5-trisphosphate (IP(3)) via...
Voltage-gated Cav1.2 channels are composed of the pore-forming α1C and auxiliary β α2δ subunits. Voltage-dependent conformational rearrangements subunit C-tail have been implicated in Ca2+ signal transduction. In contrast, N-tail demonstrates limited voltage-gated mobility. We asked whether these properties critical for channel function. Here we report that transient anchoring plasma membrane inhibits Ca2+-dependent slow voltage-dependent inactivation. Both subunits remain essential...
Transient increase in intracellular free Ca2+ concentration generated by the voltage-gated Cav1.2 channels acts as an important signal. By using fluorescence resonance energy transfer combined with patch clamp living cells, we present evidence for mobility of cytoplasmic tails channel and its regulatory role signaling. Anchoring C-terminal tail to plasma membrane caused inhibition state-dependent mobility, inactivation, CREB-dependent transcription. Release restored these functions...
1. Toxins from invertebrates have proved useful tools for investigation of the properties ion channels. In this study we describe actions arginine polyamine which is believed to be a close analogue FTX, isolated American funnel web spider, Agelenopsis aperta. 2. Voltage-activated Ca2+ currents and Ca(2+)-dependent Cl- recorded rat cultured dorsal root ganglion neurones were reversibly inhibited by (AP; 0.001 100 microM). Low voltage-activated T-type significantly more sensitive AP than high...
It is generally accepted that to generate calcium currents in response depolarization, Ca v 1.2 channels require association of the pore-forming α 1C subunit with accessory β and 2 δ subunits. A single calmodulin (CaM) molecule tethered C-terminal -LA/IQ region mediates 2+ -dependent inactivation channel. subunits are stably associated -interaction domain site cytoplasmic linker between internal repeats I II also interact dynamically, a manner, -IQ region. Here, we describe surprising...
Ca(v)beta subunits support voltage gating of Ca(v)1.2 calcium channels and play important role in excitation-contraction coupling. The common central membrane-associated guanylate kinase (MAGUK) region binds to the alpha-interaction domain (AID) IQ motif pore-forming alpha(1C) subunit, but these two interactions do not explain why cardiac Ca(v)beta(2) subunit splice variants differentially modulate inactivation Ca(2+) currents (I(Ca)). Previously we described beta(2Deltag), a functionally...
The voltage-gated K<sub>v</sub>2.1 channel is composed of four identical subunits folded around the central pore and does not inactivate appreciably during short depolarizing pulses. To study voltage-induced relative molecular rearrangements channel, were genetically fused with enhanced cyan fluorescent protein and/or yellow protein, expressed in COS1 cells, investigated using fluorescence resonance energy transfer (FRET) microscopy combined patch clamp. Fusion fluorophores to either or both...
Two new short splice variants of the Ca2+ channel beta2 subunit were cloned from human heart poly(A)(+) mRNA. The 410-amino acid beta2f is encoded by exons 1A, 2A, 3, 4, 12, 13, and 14 Cavbeta2 gene lacks protein kinase A phosphorylation site, beta-interaction domain (De Waard, M., Pragnell, Campbell, K. P. (1994) Neuron 495-503), 40% beta-SH3 domain, 73% guanylate putative membrane-associated kinases module (McGee, A. W., Nunziato, D. A., Maltez, J. Prehoda, E., Pitt, G. S., Bredt, S....
Calcium entry, via a dihydropyridine-sensitive pathway, is required for differentiation in murine erythroleukemia cells (MELC). channel currents have been identified physiologically some non-excitable cells, but little known regarding the structure of these channels. We show that truncated form α1 subunit cardiac voltage-gated calcium (dihydropyridine receptor, DHPR) expressed MELC. This MELC lacks first four transmembrane segments DHPR (IS1 to IS4). A channel/cardiac chimera, co-expressed...
Spontaneous firing of sinoatrial (SA) node cells (SANCs) is regulated by cyclic adenosine monophosphate (cAMP)-mediated, protein kinase A (PKA)-dependent (cAMP/PKA) local subsarcolemmal Ca2+ releases (LCRs) from ryanodine receptors (RyR). The LCRs occur during diastolic depolarization (DD) and activate an inward Na+/Ca2+ exchange current that accelerates the DD rate prompting next action potential (AP). Basal phosphodiesterases (PDEs) activation degrades cAMP, reduces basal...
Voltage-gated calcium channels conduct Ca(2+) ions in response to membrane depolarization. The resulting transient increase cytoplasmic free concentration is a critical trigger for the initiation of such vital responses as muscle contraction and transcription. L-type Ca(v)1.2 are complexes pore-forming α(1C) subunit associated with cytosolic Ca(v)β subunits. All major Ca(v)βs share highly homologous guanylate kinase-like (MAGUK) domain that binds at α-interaction (AID), short motif linker...
Voltage-gated Cav1.2 calcium channels couple membrane depolarization to cAMP response-element-binding protein (CREB)-dependent transcriptional activation. To investigate the spatial and temporal organization of CREB-dependent nuclear microdomains, we combined perforated patch-clamp technique FRET microscopy for monitoring CREB CREB-binding interaction in nuclei live cells. The experimental approach quantitative assessment signaling evoked by cAMP- Cav1.2-dependent mechanisms was devised COS1...
Voltage-gated Ca(v)1.2 calcium channels play a crucial role in Ca(2+) signaling. The pore-forming alpha(1C) subunit is regulated by accessory Ca(v)beta subunits, cytoplasmic proteins of various size encoded four different genes (Ca(v)beta(1)-beta(4)) and expressed tissue-specific manner.Here we investigated the effect three major types, beta(1b), beta(2d) beta(3), on structure plasma membrane live cells. Total internal reflection fluorescence microscopy showed that tendency to form clusters...