Internalization of the Kv1.4 potassium channel is suppressed by clustering interactions with PSD-95

Denis G.M. Jugloff, Rajesh Khanna, Lyanne C. Schlichter, Owen T. Jones

Research output: Contribution to journalArticle

93 Scopus citations

Abstract

The contribution of voltage-dependent ion channels to nerve function depends upon their cell-surface distributions. Nevertheless, the mechanisms underlying channel localization are poorly understood. Two phenomena appear particularly important: the clustering of channels by membrane-associated guanylate kinases (MAGUKs), such as PSD-95, and the regional stabilization of cell-surface proteins by differential suppression of endocytosis. Could these phenomena be related? To test this possibility we examined the effect of PSD- 95 on the internalization rate of Kv1.4 K+ channels in transfected HEK293 cells using cell-surface biotinylation assays. When expressed alone Kv1.4 was internalized with a half-life of 87 min, but, in the presence of PSD-95, Kv1.4 internalization was completely suppressed. Immunochemistry and electrophysiology showed PSD-95 had little effect on total or cell-surface levels of Kv1.4 or on current amplitude, activation, or inactivation kinetics. Clustering was necessary and sufficient to suppress Kv1.4 internalization since C35S-PSD-95, a mutant reported to bind but not cluster Kv1.4, (confirmed by imaging cells co-expressing a functional, GFP-variant- tagged Kv1.4) restored and, surprisingly, enhanced the rate of Kv1.4 internalization (t 1/2 = 16 min). These data argue PSD-95-mediated clustering suppresses Kv1.4 internalization and suggest a fundamentally new role for PSD-95, and perhaps other MAGUKs, orchestrating the stabilization of channels at the cell-surface.

Original languageEnglish (US)
Pages (from-to)1357-1364
Number of pages8
JournalJournal of Biological Chemistry
Volume275
Issue number2
DOIs
StatePublished - Jan 14 2000
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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