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This paper reports our contribution to the 2013 NLI Shared Task. The purpose of the task was to train a machine-learning system to identify the native-language affiliations of 1,100 texts written in English by nonnative speakers as part of a high-stakes test of general academic English proficiency. We trained our system on the new TOEFL11 corpus, which(More)
We have reported recently that syntaxin 1A mediates two effects on N-type channels transiently expressed in tsA-201 cells: a hyperpolarizing shift in the steady-state inactivation curve as well as a tonic inhibition of the channel by G-protein betagamma subunits (Jarvis et al., 2000). Here we have examined some of the molecular determinants and factors that(More)
Using transient calcium phosphate transfection into the human embryonic kidney tsa-201 cell line and subsequent whole-cell patch-clamp protocols, we examined the tonic modulation of cloned N- and P/Q-type calcium channels by five different G protein beta subunits via strong depolarizing voltage prepulses. For N- and P/Q-type channels, the magnitude of(More)
We recently described domains II and III as important determinants of fast, voltage-dependent inactivation of R-type calcium channels (Spaetgens, R. L., and Zamponi, G. W. (1999) J. Biol. Chem. 274, 22428-22438). Here we examine in greater detail the structural determinants of inactivation using a series of chimeras comprising various regions of wild type(More)
The direct modulation of N-type calcium channels by G protein betagamma subunits is considered a key factor in the regulation of neurotransmission. Some of the molecular determinants that govern the binding interaction of N-type channels and Gbetagamma have recently been identified (see, i.e., Zamponi, G. W., Bourinet, E., Nelson, D., Nargeot, J., and(More)
Ca 2+ influx through neuronal voltage-dependent Ca 2+ channels mediates a range of cytoplasmic responses, including the release of neurotransmitters, activation of Ca 2+-dependent enzymes and regulation of neuronal excitability 1,2. Several disorders have been linked to excessive Ca 2+ entry into the cytosol, and mutations and deletions in genes encoding Ca(More)
Cysteine string proteins (CSPs) are secretory vesicle proteins bearing a "J domain" and a palmitoylated cysteine-rich "string" region that are critical for neurotransmitter release. The precise role of CSP in neurotransmission is controversial. Here, we demonstrate a novel interaction between CSP, receptor-coupled trimeric GTP binding proteins (G proteins),(More)
Voltage-dependent inactivation of calcium channels is a key mechanism for regulating intracellular calcium levels and neuronal excitability. In sodium and potassium channels, the molecular determinants that govern fast inactivation involve pore block by a cytoplasmic gating particle. As we discuss here, there is an increasing body of evidence that is(More)
The modulation of N-type calcium current by protein kinases and G-proteins is a factor in the fine tuning of neurotransmitter release. We have previously shown that phosphorylation of threonine 422 in the alpha(1B) calcium channel domain I-II linker region resulted in a dramatic reduction in somatostatin receptor-mediated G-protein inhibition of the(More)
We report here that unlike what was suggested for many vertebrate neurons, synaptic transmission in Lymnaea stagnalis occurs independent of a physical interaction between presynaptic calcium channels and a functional complement of SNARE proteins. Instead, synaptic transmission in Lymnaea requires the expression of a C-terminal splice variant of the Lymnaea(More)