Casein kinase-mediated phosphorylation of serine 839 is necessary for basolateral localization of the Ca<sup>2+</sup>-activated non-selective cation channel TRPM4

Oscar Cerda, Mónica Cáceres, Kang Sik Park, Elías Leiva-Salcedo, Aníbal Romero, Diego Varela, James Trimmer, Andrés Stutzin

Research output: Contribution to journalArticle

5 Scopus citations

Abstract

Transient receptor potential melastatin-like 4 (TRPM4) is a Ca<sup>2+</sup>-activated non-selective cation channel expressed in a wide range of human tissues. TRPM4 participates in a variety of physiological processes such as T cell activation, myogenic vasoconstriction, and allergic reactions. TRPM4 Ca<sup>2+</sup> sensitivity is enhanced by calmodulin (CaM) and phosphathydilinositol 4, 5-bisphosphate (PI(4,5)P<inf>2</inf>) binding, as well as, under certain conditions, PKC activation. However, information as to the mechanisms of modulation of this channel remains unknown, including direct identification of phosphorylation sites on TRPM4 and their role in channel features. Here, we use mass-spectrometric-based proteomic approaches (immunoprecipitation and tandem mass spectrometry) to unambiguously identify S839 as a phosphorylation site present on human TRPM4 expressed in a human cell line. Site-directed mutagenesis employing a serine to alanine mutation to eliminate phosphorylation, and a phospho-mimetic aspartate mutation, as well as biochemical and immunocytochemical experiments, revealed a role for S839 phosphorylation in the basolateral expression of TRPM4 channels in epithelial cells. Moreover, we demonstrated that casein kinase 1 (CK1) phosphorylates S839 and is responsible for the basolateral localization of TRPM4.

Original languageEnglish (US)
Pages (from-to)1723-1732
Number of pages10
JournalPflugers Archiv European Journal of Physiology
Volume467
Issue number8
DOIs
StatePublished - Aug 24 2015

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Keywords

  • Basolateral
  • Casein kinase
  • LC-MS/MS
  • Phosphorylation
  • TRP channels

ASJC Scopus subject areas

  • Physiology
  • Clinical Biochemistry
  • Physiology (medical)

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