Modulation of Na+channel inactivation by the β1 subunit: A deletion analysis

Chinfei Chen, Stephen C. Cannon

Research output: Contribution to journalArticle

63 Scopus citations

Abstract

Na+ currents recorded from Xenopus oocytes expressing the Na+ channel α subunit alone inactivate with two exponential components. The slow component predominates in monomeric channels, while coexpression with the β1 subunit favors the fast component. Macropatch recordings show that the relative rates of these components are much greater than previously estimated from two-electrode measurements (≈30-fold vs ≈5-fold). A re-assessment of steady-state inactivation, h(V), shows that there is no depolarized shift of the slow component, provided a sufficiently long prepulse duration and repetition interval are used to achieve steady-state entry and recovery from inactivation, respectively. Deletion mutagenesis of the β1 subunit was used to define which regions of the subunit are required to modulate inactivation kinetics. The carboxy tail, comprising the entire predicted intracellular domain, can be deleted without a loss of activity; whereas small deletions in the extracellular amino domain or the signal peptide totally disrupt function.

Original languageEnglish (US)
Pages (from-to)186-195
Number of pages10
JournalPflügers Archiv European Journal of Physiology
Volume431
Issue number2
DOIs
StatePublished - Dec 1 1995

Keywords

  • Gating
  • Sodium channel
  • Xenopus oocyte
  • β Subunit

ASJC Scopus subject areas

  • Physiology
  • Clinical Biochemistry
  • Physiology (medical)

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