Multisite phosphorylation of voltage-gated sodium channel α subunits from rat brain

Frank J. Berendt, Kang Sik Park, James Trimmer

Research output: Contribution to journalArticle

37 Scopus citations

Abstract

Reversible phosphorylation of ion channels underlies cellular plasticity in mammalian neurons. Voltage-gated sodium or Nav channels underlie action potential initiation and propagation, dendritic excitability, and many other aspects of neuronal excitability. Various protein kinases have been suggested to phosphorylate the primary or α subunit of Nav channels, affecting diverse aspects of channel function. Previous studies of Nav α subunit phosphorylation have led to the identification of a small set of phosphorylation sites important in mediating diverse aspects of Nav channel function. Here we use nanoflow liquid chromatography tandem mass spectrometry (nano-LC MS/MS) on Nav α subunits affinity-purified from rat brain with two distinct monoclonal antibodies to identify 15 phosphorylation sites on Nav1.2, 12 of which have not been previously reported. We also found 3 novel phosphorylation sites on Nav1.1. In general, commonly used phosphorylation site prediction algorithms did not accurately predict these novel in vivo phosphorylation sites. Our results demonstrate that specific Nav α subunits isolated from rat brain are highly phosphorylated, and suggest extensive modulation of Nav channel activity in mammalian brain. Identification of phosphorylation sites using monoclonal antibody-based immunopurification and mass spectrometry is an effective approach to define the phosphorylation status of Nav channels and other important membrane proteins in mammalian brain.

Original languageEnglish (US)
Pages (from-to)1976-1984
Number of pages9
JournalJournal of Proteome Research
Volume9
Issue number4
DOIs
StatePublished - Apr 5 2010

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Keywords

  • Brain
  • Immunopurification
  • Monoclonal antibody
  • Nanoflow liquid chromatography
  • Phosphorylation
  • Tandem mass spectrometry
  • Voltage-gated sodium channels

ASJC Scopus subject areas

  • Biochemistry
  • Chemistry(all)

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