A dystroglycan/plectin scaffold mediates mechanical pathway bifurcation in lung epithelial cells

J Biol Chem. 2011 Feb 25;286(8):6301-10. doi: 10.1074/jbc.M110.178988. Epub 2010 Dec 13.

Abstract

In alveolar epithelial cells (AECs), the membrane-anchored proteoglycan dystroglycan (DG) is a mechanoreceptor that transmits mechanical stretch forces to activate independently the ERK1/2 and the adenosine 5'-monophosphate-activated protein kinase (AMPK) signaling cascades in a process called pathway bifurcation. We tested the hypothesis that the cytoskeleton cross-linker plectin, known to bind both DG and AMPK in muscle cells, acts as a scaffold to regulate DG-mediated mechanical stimulation and pathway bifurcation. We demonstrate that plectin and DG form a complex in AECs and that this complex interacts with ERK1/2 and AMPK. Plectin knockdown reduces DG interaction with AMPK but not with ERK1/2. Despite this, mechanoactivation of both signaling pathways is significantly attenuated in AECs deficient in plectin. Thus, DG has the dual role of mechanical receptor and scaffold for ERK1/2, whereas plectin acts as a scaffold for AMPK signaling but is also required for DG-mediated ERK1/2 activation. We conclude that the DG-plectin complex plays a central role in transmitting mechanical stress from the extracellular matrix to the cytoplasm.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • AMP-Activated Protein Kinases / genetics
  • AMP-Activated Protein Kinases / metabolism
  • Animals
  • Cell Line
  • Cytoplasm / genetics
  • Cytoplasm / metabolism
  • Dystroglycans / genetics
  • Dystroglycans / metabolism*
  • Enzyme Activation / physiology
  • Epithelial Cells / cytology
  • Epithelial Cells / metabolism*
  • Extracellular Matrix / genetics
  • Extracellular Matrix / metabolism
  • Gene Knockdown Techniques
  • MAP Kinase Signaling System / physiology*
  • Male
  • Mechanotransduction, Cellular / physiology*
  • Mitogen-Activated Protein Kinase 3 / genetics
  • Mitogen-Activated Protein Kinase 3 / metabolism
  • Plectin / genetics
  • Plectin / metabolism*
  • Pulmonary Alveoli / cytology
  • Pulmonary Alveoli / metabolism*
  • Rats
  • Rats, Sprague-Dawley

Substances

  • Plectin
  • Dystroglycans
  • Mitogen-Activated Protein Kinase 3
  • AMP-Activated Protein Kinases