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Single-channel and [3H]ryanodine binding experiments were carried out to examine the effects of imperatoxin activator (IpTxa), a 33 amino acid peptide isolated from the venom of the African scorpion Pandinus imperator, on rabbit skeletal and canine cardiac muscle Ca2+ release channels (CRCs). Single channel currents from purified CRCs incorporated into(More)
The effects of the two local anesthetics tetracaine and procaine and a quaternary amine derivative of lidocaine, QX314, on sarcoplasmic reticulum (SR) Ca2+ release have been examined by incorporating the purified rabbit skeletal muscle Ca2+ release channel complex into planar lipid bilayers. Recordings of potassium ion currents through single channels(More)
Current voltage (I-V) relations were measured from the calcium release channel (CRC) of the sarcoplasmic reticulum of cardiac muscle in 12 KCl solutions, symmetrical and asymmetrical, from 25 mM to 2 M. I-V curves are nearly linear, in the voltage range +/- 150 mV approximately 12kT/e, even in asymmetrical solutions, e.g., 2 M // 100 mM. It is awkward to(More)
Ion channels have been studied extensively in ambient O2 tension (pO2), whereas tissue PO2 is much lower. The skeletal muscle calcium release channel/ryanodine receptor (RyR1) is one prominent example. Here we report that PO2 dynamically controls the redox state of 6-8 out of 50 thiols in each RyR1 subunit and thereby tunes the response to NO. At(More)
Ryanodine receptor type 1 (RyR1) releases Ca(2+) from intracellular stores upon nerve impulse to trigger skeletal muscle contraction. Effector binding at the cytoplasmic domain tightly controls gating of the pore domain of RyR1 to release Ca(2+). However, the molecular mechanism that links effector binding to channel gating is unknown due to lack of(More)
Sequence comparison suggests that the ryanodine receptors (RyRs) have pore architecture similar to that of the bacterial K+ channel KcsA. The lumenal loop linking the two most C-terminal transmembrane spanning segments in the RyRs has a predicted pore helix and an amino acid motif (GGGIG) similar to the selectivity filter (TVGYG) of KcsA identified by x-ray(More)
We tested the hypothesis that part of the lumenal amino acid segment between the two most C-terminal membrane segments of the skeletal muscle ryanodine receptor (RyR1) is important for channel activity and conductance. Eleven mutants were generated and expressed in HEK293 cells focusing on amino acid residue I4897 homologous to the selectivity filter of(More)
Viral pathogens are a major threat to rice production worldwide. Although RNA interference (RNAi) is known to mediate antiviral immunity in plant and animal models, the mechanism of antiviral RNAi in rice and other economically important crops is poorly understood. Here, we report that rice resistance to evolutionarily diverse viruses requires Argonaute18(More)
— In mobile cloud computing, mobile devices can rely on cloud computing and information storage resource to perform computationally intensive operations such as searching, data mining, and multimedia processing. In addition to providing traditional computation services, mobile cloud also enhances the operation of traditional ad hoc network by treating(More)
We have characterized at the molecular level, three families with core myopathies carrying apparent recessive mutations in their RYR1 gene and studied the pharmacological properties of myotubes carrying endogenous mutations as well as the properties of mutant channels expressed in HEK293 cells. The proband of family 1 carried p.Ala1577Thr+p.Gly2060Cys in(More)