APPL1 mediates adiponectin-stimulated p38 MAPK activation by scaffolding the TAK1-MKK3-p38 MAPK pathway

Xiaoban Xin, Lijun Zhou, Caleb M. Reyes, Feng Liu, Lily Q. Dong

Research output: Contribution to journalArticle

55 Scopus citations

Abstract

The adaptor protein APPL1 mediates the stimulatory effect of adiponectin on p38 mitogen-activated protein kinase (MAPK) signaling, yet the underlying mechanism remains unclear. Here we show that, in C2C12 cells, overexpression or suppression of APPL1 enhanced or suppressed, respectively, adiponectin-stimulated p38 MAPK upstream kinase cascade, consisting of transforming growth factor-β-activated kinase 1 (TAK1) and mitogen-activated protein kinase kinase 3 (MKK3). In vitro affinity binding and coimmunoprecipitation experiments revealed that TAK1 and MKK3 bind to different regions of APPL1, suggesting that APPL1 functions as a scaffolding protein to facilitate adiponectin-stimulated p38 MAPK activation. Interestingly, suppressing APPL1 had no effect on TNFα-stimulated p38 MAPK phosphorylation in C2C12 myotubes, indicating that the stimulatory effect of APPL1 on p38 MAPK activation is selective. Taken together, our study demonstrated that the TAK1-MKK3 cascade mediates adiponectin signaling and uncovers a scaffolding role of APPL1 in regulating the TAK1-MKK3-p38 MAPK pathway, specifically in response to adiponectin stimulation.

Original languageEnglish (US)
Pages (from-to)E103-E110
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Volume300
Issue number1
DOIs
StatePublished - Jan 2011

Keywords

  • APPL1
  • Mitogen-activated protein kinase kinase 3
  • Transforming growth factor-β-activated kinase 1
  • p38 mitogen-activated protein kinase

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Physiology
  • Physiology (medical)

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