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Titolo:
Identification of a peptide toxin from Grammostola spatulata spider venom that blocks cation-selective stretch-activated channels
Autore:
Suchyna, TM; Johnson, JH; Hamer, K; Leykam, JF; Gage, DA; Clemo, HF; Baumgarten, CM; Sachs, F;
Indirizzi:
SUNY Buffalo, Dept Physiol & Biophys, Buffalo, NY 14214 USA SUNY Buffalo Buffalo NY USA 14214 hysiol & Biophys, Buffalo, NY 14214 USA NPS Pharmaceut Inc, Salt Lake City, UT 84108 USA NPS Pharmaceut Inc Salt Lake City UT USA 84108 lt Lake City, UT 84108 USA Virginia Commonwealth Univ, Med Coll Virginia, Dept Internal Med & Physiol, Richmond, VA 23298 USA Virginia Commonwealth Univ Richmond VA USA 23298 , Richmond, VA 23298 USA Michigan State Univ, Dept Biochem, Natl Inst Hlth Mass Spectrometry Facil,E Lansing, MI 48824 USA Michigan State Univ E Lansing MI USA 48824 Facil,E Lansing, MI 48824 USA
Titolo Testata:
JOURNAL OF GENERAL PHYSIOLOGY
fascicolo: 5, volume: 115, anno: 2000,
pagine: 583 - 598
SICI:
0022-1295(200005)115:5<583:IOAPTF>2.0.ZU;2-I
Fonte:
ISI
Lingua:
ENG
Soggetto:
MECHANOTRANSDUCING ION CHANNELS; SWELLING-INDUCED CHANGES; CELL-VOLUME REGULATION; ASCITES TUMOR-CELLS; CULTURED ASTROCYTES; XENOPUS OOCYTES; TRANSPORT PATHWAYS; CALCIUM-CHANNEL; ELECTROPHYSIOLOGICAL PROPERTIES; MECHANOSENSITIVE CHANNELS;
Keywords:
mechanogated; swell; astrocyte; ventricular; myocytes;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
58
Recensione:
Indirizzi per estratti:
Indirizzo: Suchyna, TM SUNY Buffalo, Dept Physiol & Biophys, 320 Cary Hall, Buffalo, NY 14214 USA SUNY Buffalo 320 Cary Hall Buffalo NY USA 14214 , NY 14214 USA
Citazione:
T.M. Suchyna et al., "Identification of a peptide toxin from Grammostola spatulata spider venom that blocks cation-selective stretch-activated channels", J GEN PHYSL, 115(5), 2000, pp. 583-598

Abstract

We have identified a 35 amino acid peptide toxin of the inhibitor cysteineknot family that blocks cationic stretch-activated ion channels. The toxin, denoted GsMTx-4, was isolated from the venom of the spider Grammostola spatulata and has <50% homology to other neuroactive peptides. It was isolated by fractionating whole venom using reverse phase HPLC, and then assaying fractions on stretch-activated channels (SACs) in outside-out patches from adult rat astrocytes. Although the channel gating kinetics were different between cell-attached and outside-out patches, the properties associated with the channel pore, such as selectivity for alkali cations, conductance (similar to 45 pS at -100 mV) and a mild rectification were unaffected by outside-out formation. GsMT-4 produced a complete block of SACs in outside-out patches and appeared specific since it had no effect on whole-cell voltage-sensitive currents. The equilibrium dissociation constant of similar to 630nM was calculated from the ratio of association and dissociation rate constants. In hypotonically swollen astrocytes, GsMTx-4 produces similar to 40%reduction in swelling-activated whole-cell current. Similarly, in isolatedventricular cells from a rabbit dilated cardiomyopathy model, GsMTx-4 produced a near complete block of the volume-sensitive cation-selective current, but did not affect the anion current. In the myopathic heart cells, wherethe swell-induced current is tonically active, GsMTx-4 also reduced the cell size. This is the first report of a peptide toxin that specifically blocks stretch-activated currents. The toxin affect on swelling-activated whole-cell currents implicates SACs in volume regulation.

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Documento generato il 30/10/20 alle ore 23:52:38