Imperatoxin A (IpTxa ) from Pandinus imperator stimulates [3 H]ryanodine binding to RyR3 channels

Autor: Jesús García, Vincenzo Sorrentino, Xinsheng Zhu, Daniela Rossi, Héctor H. Valdivia, Ilenia Simeoni
Rok vydání: 2001
Předmět:
genetics/metabolism
Stimulation
medicine.disease_cause
Biochemistry
Ryanodine receptor 2
Structural Biology
Protein Isoforms
Cells
Cultured
Cultured
Ryanodine
Ryanodine receptor
Skeletal
musculoskeletal system
Immunohistochemistry
Electrophysiology
chemistry/metabolism
Muscle
Calcium release channel
tissues
Excitation contraction coupling
chemistry/drug effects
medicine.medical_specialty
animal structures
Cells
Sarcoplasmic reticulum
Biophysics
Scorpion Venoms
chemistry.chemical_element
Calcium
chemistry
Tritium
Scorpions
Microsomes
Internal medicine
Genetics
medicine
Animals
Muscle
Skeletal
Molecular Biology
RYR1
Toxin
Endoplasmic reticulum
T-type calcium channel
Ryanodine Receptor Calcium Release Channel
Cell Biology
Animals
Calcium
metabolism
Cattle
Cells
Cultured
Electrophysiology
Immunohistochemistry
Microsomes
chemistry/drug effects
Muscle
metabolism
Protein Isoforms
metabolism
Ryanodine Receptor Calcium Release Channel
genetics/metabolism
Ryanodine
chemistry/metabolism
Scorpion Venoms
pharmacology
Scorpions
chemistry
Tritium
Endocrinology
Cattle
pharmacology
metabolism
Zdroj: FEBS Letters. 508:5-10
ISSN: 0014-5793
DOI: 10.1016/s0014-5793(01)03013-7
Popis: The effect of imperatoxin A (IpTx(a)) on the ryanodine receptor type 3 (RyR3) was studied. IpTx(a) stimulates [(3)H]ryanodine binding to RyR3-containing microsomes, but this effect requires toxin concentrations higher than those required to stimulate RyR1 channels. The effect of IpTx(a) on RyR3 channels was observed at calcium concentrations in the range 0.1 microM to 10 mM. By contrast, RyR2 channels were not significantly affected by IpTx(a) in the same calcium ranges. Single channel current measurements indicated that IpTx(a) induced subconductance state in RyR3 channels that was similar to those observed with RyR1 and RyR2 channels. These results indicate that IpTx(a) is capable of inducing similar subconductance states in all three RyR isoforms, while stimulation of [(3)H]ryanodine binding by this toxin results in isoform-specific responses, with RyR1 being the most sensitive channel, RyR3 displaying an intermediate response and RyR2 the least responsive ones.
Databáze: OpenAIRE
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