Episodic ataxia type-1 mutations in the hKv1.1 cytoplasmic pore region alter the gating properties of the channel

Maria Cristina D'Adamo, Zhaoping Liu, John Adelman, James Maylie, Mauro Pessia

Research output: Contribution to journalArticle

60 Citations (Scopus)

Abstract

Episodic ataxia type-1 is a rare human neurological syndrome which occurs during childhood and persists through the whole life of affected patients. Several heterozygous point mutations have been found in the coding sequence of the voltage-gated potassium channel gene hKv1.1 of different affected families. V408A and E325D mutations are located in the cytoplasmic putative pore region of hKv1.1 channels and profoundly alter their gating properties. V408A channels showed increased kinetic rates of activation, deactivation and C-type inactivation. Expression of E325D channels in Xenopus oocytes led to an ~13-fold current amplitude reduction and to a 52.4 mV positive shift in the voltage dependence of activation. Moreover, the E325D mutation altered the kinetics of activation, deactivation, C-type inactivation and channel open probability. Heteromeric channels composed of two wild-type and two mutated subunits, linked as dimers, showed gating properties intermediate between channels formed from four normal or four mutated subunits. The results demonstrate that the highly conserved residues Val408 and Glu325 play a pivotal role in several gating processes of a human potassium channel, and suggest a pathogenetic mechanism by which the impairment of the delayed-rectifier function of affected neurons is related to the type and number of mutated subunits which make up the hKv1.1 channels.

Original languageEnglish (US)
Pages (from-to)1200-1207
Number of pages8
JournalEMBO Journal
Volume17
Issue number5
DOIs
StatePublished - Mar 2 1998

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Chemical activation
Voltage-Gated Potassium Channels
Mutation
Potassium Channels
Xenopus
Point Mutation
Oocytes
Kinetics
Neurons
Dimers
Genes
Electric potential
Type 1 Episodic Ataxia

Keywords

  • Channels
  • Episodic ataxia type-1
  • Gating
  • hKv1.1
  • Mutation
  • Potassium channel

ASJC Scopus subject areas

  • Genetics
  • Cell Biology

Cite this

Episodic ataxia type-1 mutations in the hKv1.1 cytoplasmic pore region alter the gating properties of the channel. / D'Adamo, Maria Cristina; Liu, Zhaoping; Adelman, John; Maylie, James; Pessia, Mauro.

In: EMBO Journal, Vol. 17, No. 5, 02.03.1998, p. 1200-1207.

Research output: Contribution to journalArticle

D'Adamo, Maria Cristina ; Liu, Zhaoping ; Adelman, John ; Maylie, James ; Pessia, Mauro. / Episodic ataxia type-1 mutations in the hKv1.1 cytoplasmic pore region alter the gating properties of the channel. In: EMBO Journal. 1998 ; Vol. 17, No. 5. pp. 1200-1207.
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