ArticleThe Journal of general physiology1998
Imperatoxin A induces subconductance states in Ca2+ release channels (ryanodine receptors) of cardiac and skeletal muscle.
Article in The Journal of general physiology, 1998. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 48 papers.
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Who cites it
48 citing papers in PubMed, 93 citations in OpenAlex.
- Old dog, new trick: Charybdotoxin as a novel ryanodine receptor blocker.The Journal of physiology · 2026Article
- The Venom Revolution in Biomedicine: Unlocking Nature's Toxin Toolkit for Therapeutic Innovation.Toxicology reports · 2026Review
- Cryo-EM Brings the Mechanisms of Activation, Inactivation, and Inhibition of Ryanodine Receptors into Focus.Advances in experimental medicine and biology · 2026Review
- Cryo-EM analysis of scorpion toxin binding to Ryanodine Receptors reveals subconductance that is abolished by PKA phosphorylation.Science advances · 2023Article
- A bivalent remipede toxin promotes calcium release via ryanodine receptor activation.Nature communications · 2023Article
- Excitation-contraction coupling in mammalian skeletal muscle: Blending old and last-decade research.Frontiers in physiology · 2022Review
- Australian ScorpionBiomolecules · 2020Article
- Toxins from scratch? Diverse, multimodal gene origins in the predatory robber fly Dasypogon diadema indicate a dynamic venom evolution in dipteran insects.GigaScience · 2019Article
- Recombinant expression of Intrepicalcin from the scorpion Vaejovis intrepidus and its effect on skeletal ryanodine receptors.Biochimica et biophysica acta. General subjects · 2017Article
- A guide to the 3D structure of the ryanodine receptor type 1 by cryoEM.Protein science : a publication of the Protein Society · 2017Review
- Transport of Calcium Ions into Mitochondria.Current genomics · 2016Article
- Structure-function relationships of peptides forming the calcin family of ryanodine receptor ligands.The Journal of general physiology · 2016Article
- Approaching ryanodine receptor therapeutics from the calcin angle.The Journal of general physiology · 2016Article
- Caffeine-Induced Suppression of GABAergic Inhibition and Calcium-Independent Metaplasticity.Neural plasticity · 2016Article
- Insights into the gating mechanism of the ryanodine-modified human cardiac Ca2+-release channel (ryanodine receptor 2).Molecular pharmacology · 2014Article
- Scorpion venom components that affect ion-channels function.Toxicon : official journal of the International Society on Toxinology · 2013Review
- Article
- Multiple actions of phi-LITX-Lw1a on ryanodine receptors reveal a functional link between scorpion DDH and ICK toxins.Proceedings of the National Academy of Sciences of the United States of America · 2013Article
- Both basic and acidic amino acid residues of IpTx(a) are involved in triggering substate of RyR1.Journal of biomedicine & biotechnology · 2011Article
- Ryanodol action on calcium sparks in ventricular myocytes.Pflugers Archiv : European journal of physiology · 2010Article
Corrections and comments
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Authors and funding
5 authors at 1 institution in 1 country.
Funding
Abstract
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 planar lipid bilayers were recorded in 250 mM KCl media. Addition of IpTxa in nanomolar concentration to the cytosolic (cis) side, but not to the lumenal (trans) side, induced substates in both ryanodine receptor isoforms. The substates displayed a slightly rectifying current-voltage relationship. The chord conductance at -40 mV was approximately 43% of the full conductance, whereas it was approximately 28% at a holding potential of +40 mV. The substate formation by IpTxa was voltage and concentration dependent. Analysis of voltage and concentration dependence and kinetics of substate formation suggested that IpTxa reversibly binds to the CRC at a single site in the voltage drop across the channel. The rate constant for IpTxa binding to the skeletal muscle CRC increased e-fold per +53 mV and the rate constant of dissociation decreased e-fold per +25 mV applied holding potential. The effective valence of the reaction leading to the substate was approximately 1.5. The IpTxa binding site was calculated to be located at approximately 23% of the voltage drop from the cytosolic side. IpTxa induced substates in the ryanodine-modified skeletal CRC and increased or reduced [3H]ryanodine binding to sarcoplasmic reticulum vesicles depending on the level of channel activation. These results suggest that IpTxa induces subconductance states in skeletal and cardiac muscle Ca2+ release channels by binding to a single, cytosolically accessible site different from the ryanodine binding site.
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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.