Neutral sphingomyelinase 2 (nSMase2) is a phosphoprotein regulated by calcineurin (PP2B)

Simone Filosto, William Fry, Anne A Knowlton, Tzipora Goldkorn

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

We previously reported that exposure of human airway epithelial cells to oxidative stress increased ceramide generation via specific activation of neutral sphingomyelinase2 (nSMase2). Here we show that nSMase2 is a phosphoprotein exclusively phosphorylated at serine residues. The level of nSMase2 phosphorylation can be modulated by treatment with anisomycin or phorbol 12-myristate 13-acetate (PMA/12-O-tetradecanoylphorbol-13-acetate), suggesting that p38 mitogen-activated protein kinase (MAPK) and protein kinases Cs are upstream of nSMase2 phosphorylation. Oxidative stress enhances both the activity and phosphorylation of nSMase2. Strikingly, we show here that nSMase2 is bound directly by the phosphatase calcineurin (CaN), which acts as an on/off switch for nSMase2 phosphorylation in the presence or absence of oxidative stress. Specifically, CaN is being inhibited/degraded and therefore does not bind nSMase2 under oxidative stress, and a mutant nSMase2 that lacks the CaN binding site exhibits constitutively elevated phosphorylation and increased activity relative to wild type nSMase2. Importantly, the phosphorylation and activity of the mutant no longer responds to oxidative stress, confirming that CaN is the critical link that allows oxidative stress to modulate nSMase2 phosphorylation and function.

Original languageEnglish (US)
Pages (from-to)10213-10222
Number of pages10
JournalJournal of Biological Chemistry
Volume285
Issue number14
DOIs
StatePublished - Apr 2 2010

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Sphingomyelin Phosphodiesterase
Calcineurin
Phosphoproteins
Phosphorylation
Oxidative stress
Oxidative Stress
p38 Mitogen-Activated Protein Kinases
Acetates
Anisomycin
Ceramides
Mitogen-Activated Protein Kinase Kinases
Tetradecanoylphorbol Acetate
Protein Kinases
Serine
Epithelial Cells
Chemical activation
Binding Sites
Switches

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Molecular Biology

Cite this

Neutral sphingomyelinase 2 (nSMase2) is a phosphoprotein regulated by calcineurin (PP2B). / Filosto, Simone; Fry, William; Knowlton, Anne A; Goldkorn, Tzipora.

In: Journal of Biological Chemistry, Vol. 285, No. 14, 02.04.2010, p. 10213-10222.

Research output: Contribution to journalArticle

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