Phosphorylation of the Kv2.1 K+ channel alters voltage-dependent activation

Hideyuki Murakoshi, Gongyi Shi, Robert H. Scannevin, James Trimmer

Research output: Contribution to journalArticle

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Abstract

The voltage-gated delayed-rectifier-type K+ channel Kv2.1 is expressed in high-density clusters on the soma and proximal dendrites of mammalian central neurons; thus, dynamic regulation of Kv2.1 would be predicted to have an impact on dendritic excitability. Rat brain Kv2.1 polypeptides are phosphorylated extensively, leading to a dramatically increased molecular mass on sodium dodecyl sulfate gels. Phosphoamino acid analysis of Kv2.1 expressed in transfected cells and labeled in vivo with 32p shows that phosphorylation was restricted to serine residues and that a truncation mutant. ΔC318, which lacks the last 318 amino acids in the cytoplasmic carboxyl terminus, was phosphorylated to a much lesser degree than was wild- type Kv2.1. Whole-cell patch-clamo studies showed that the voltage-dependence of activation of ΔC318 was shifted to more negative membrane potentials than Kv2.1 without differences in macroscopic kinetics; however, the differences in the voltage-dependence of activation between Kv2.1 and ΔC318 were eliminated by in vivo intracellular application of alkaline phosphatase, suggesting that these differences were due to differential phosphorylation. Similar analyses of other truncation and point mutants indicated that the phosphorylation sites responsible for the observed differences in voltage- dependent activation lie between amino acids 667 and 853 near the distal end of the Kv2.1 carboxyl terminus. Together, these parallel biochemical and electrophysiological results provide direct evidence that the voltage- dependent activation of the delayed-rectifier K+ channel Kv2.1 can be modulated by direct phosphorylation of the channel protein; such modulation of Kv2.1 could dynamically regulate dendritic excitability.

Original languageEnglish (US)
Pages (from-to)821-828
Number of pages8
JournalMolecular Pharmacology
Volume52
Issue number5
StatePublished - Nov 1997
Externally publishedYes

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Phosphorylation
Phosphoamino Acids
Amino Acids
Carisoprodol
Dendrites
Sodium Dodecyl Sulfate
Membrane Potentials
Serine
Alkaline Phosphatase
Gels
Neurons
Peptides
Brain
Proteins

ASJC Scopus subject areas

  • Pharmacology

Cite this

Murakoshi, H., Shi, G., Scannevin, R. H., & Trimmer, J. (1997). Phosphorylation of the Kv2.1 K+ channel alters voltage-dependent activation. Molecular Pharmacology, 52(5), 821-828.

Phosphorylation of the Kv2.1 K+ channel alters voltage-dependent activation. / Murakoshi, Hideyuki; Shi, Gongyi; Scannevin, Robert H.; Trimmer, James.

In: Molecular Pharmacology, Vol. 52, No. 5, 11.1997, p. 821-828.

Research output: Contribution to journalArticle

Murakoshi, H, Shi, G, Scannevin, RH & Trimmer, J 1997, 'Phosphorylation of the Kv2.1 K+ channel alters voltage-dependent activation', Molecular Pharmacology, vol. 52, no. 5, pp. 821-828.
Murakoshi H, Shi G, Scannevin RH, Trimmer J. Phosphorylation of the Kv2.1 K+ channel alters voltage-dependent activation. Molecular Pharmacology. 1997 Nov;52(5):821-828.
Murakoshi, Hideyuki ; Shi, Gongyi ; Scannevin, Robert H. ; Trimmer, James. / Phosphorylation of the Kv2.1 K+ channel alters voltage-dependent activation. In: Molecular Pharmacology. 1997 ; Vol. 52, No. 5. pp. 821-828.
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