The Rho target PRK2 regulates apical junction formation in human bronchial epithelial cells

Mol Cell Biol. 2011 Jan;31(1):81-91. doi: 10.1128/MCB.01001-10. Epub 2010 Oct 25.

Abstract

Rho GTPases regulate multiple signaling pathways to control a number of cellular processes during epithelial morphogenesis. To investigate the downstream pathways through which Rho regulates epithelial apical junction formation, we screened a small interfering RNA (siRNA) library targeting 28 known Rho target proteins in 16HBE human bronchial epithelial cells. This led to the identification of the serine-threonine kinase PRK2 (protein kinase C-related kinase 2, also called PKN2). Depletion of PRK2 does not block the initial formation of primordial junctions at nascent cell-cell contacts but does prevent their maturation into apical junctions. PRK2 is recruited to primordial junctions, and this localization depends on its C2-like domain. Rho binding is essential for PRK2 function and also facilitates PRK2 recruitment to junctions. Kinase-dead PRK2 acts as a dominant-negative mutant and prevents apical junction formation. We conclude that PRK2 is recruited to nascent cell-cell contacts through its C2-like and Rho-binding domains and promotes junctional maturation through a kinase-dependent pathway.

Publication types

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

MeSH terms

  • Bronchi / cytology
  • Bronchi / metabolism
  • Cell Line
  • Epithelial Cells / cytology
  • Epithelial Cells / metabolism
  • Humans
  • Intercellular Junctions / metabolism*
  • Protein Kinase C / antagonists & inhibitors
  • Protein Kinase C / chemistry
  • Protein Kinase C / genetics
  • Protein Kinase C / metabolism*
  • Protein Structure, Tertiary
  • RNA, Small Interfering / genetics
  • Signal Transduction
  • rho GTP-Binding Proteins / antagonists & inhibitors
  • rho GTP-Binding Proteins / genetics
  • rho GTP-Binding Proteins / metabolism*
  • rhoA GTP-Binding Protein / antagonists & inhibitors
  • rhoA GTP-Binding Protein / genetics
  • rhoA GTP-Binding Protein / metabolism
  • rhoC GTP-Binding Protein

Substances

  • RNA, Small Interfering
  • RHOA protein, human
  • protein kinase N
  • Protein Kinase C
  • RHOC protein, human
  • rho GTP-Binding Proteins
  • rhoA GTP-Binding Protein
  • rhoC GTP-Binding Protein