Multiple Actions of Imperatoxin A on Ryanodine Receptors
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چکیده
منابع مشابه
Multiple actions of the anthracycline daunorubicin on cardiac ryanodine receptors.
Our aim was to examine the molecular basis for acute effects of the anthracycline daunorubicin on cardiac ryanodine receptor (RyR2) channels and cardiac calsequestrin (CSQ2). Cardiotoxic effects of anthracyclines preclude their chemotherapeutic use in patients with pre-existing heart conditions. To address this significant problem, the mechanisms of anthracycline toxicity must be defined but at...
متن کاملMolecular basis of the high-affinity activation of type 1 ryanodine receptors by imperatoxin A.
Both imperatoxin A (IpTx(a)), a 33-residue peptide toxin from scorpion venom, and peptide A, derived from the II-III loop of dihydropyridine receptor (DHPR), interact specifically with the skeletal ryanodine receptor (RyR1), which is a Ca(2+)-release channel in the sarcoplasmic reticulum, but with considerably different affinities. IpTx(a) activates RyR1 with nanomolar affinity, whereas peptide...
متن کاملImperatoxin A Induces Subconductance States in Ca2+ Release Channels (Ryanodine Receptors) of Cardiac and Skeletal Muscle
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...
متن کاملImperatoxin A, a Cell-Penetrating Peptide from Scorpion Venom, as a Probe of Ca2+-Release Channels/Ryanodine Receptors
Scorpion venoms are rich in ion channel-modifying peptides, which have proven to be invaluable probes of ion channel structure-function relationship. We previously isolated imperatoxin A (IpTxa), a 3.7 kDa peptide activator of Ca(2+)-release channels/ryanodine receptors (RyRs) [1,2,3] and founding member of the calcin family of scorpion peptides. IpTxa folds into a compact, mostly hydrophobic m...
متن کاملThree-Dimensional Location of the Imperatoxin a Binding Site on the Ryanodine Receptor
Cryo-electron microscopy and three-dimensional, single-particle image analysis have been used to reveal the specific binding site of imperatoxin A (IpTx(a)) on the architecture of the calcium release channel/ryanodine receptor from skeletal muscle (RyR1). IpTx(a) is a peptide toxin that binds with high affinity to RyR1 and affects its functioning. The toxin was derivatized with biotin to enhanc...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 2004
ISSN: 0021-9258
DOI: 10.1074/jbc.m310466200