Rab11 is associated with epidermal lamellar granules

J Invest Dermatol. 2007 Sep;127(9):2166-70. doi: 10.1038/sj.jid.5700850. Epub 2007 May 3.

Abstract

Epidermal lamellar granules (LGs) are specialized organelles that transport and secrete various molecules, including lipids, proteases, protease inhibitors, and structural proteins, thereby providing a protective barrier against the environment. Abnormalities in LG-related molecules result in severe skin diseases, but their transport mechanisms are poorly understood. We studied the distribution of Rab11, a common GTPase in recycling endosomes, in normal human epidermis. Confocal laser scanning microscopy detected Rab11 immunoreactivity in differentiated epidermal keratinocytes. Staining was strong at the apical side of each cell, a pattern commonly seen in LG-associated molecules. Around the nuclei, Rab11 was colocalized with TGN46, a trans-Golgi network marker. Rab11 was also colocalized with known LG-molecules, namely lymphoepithelial Kazal-type-related inhibitor, corneodesmosine, cathepsin D, and glucosylceramides. Immunoelectron microscopy revealed that Rab11 was widely distributed along TGN and tubular-vesicular structures containing different LG molecules. The present results suggest that Rab11 plays a role in the intracellular trafficking of various types of LG-molecule from the TGN to the cell surface.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cathepsin D / metabolism
  • Cell Membrane / metabolism
  • Endosomes / metabolism
  • Epidermis / metabolism*
  • Glucosylceramides / metabolism
  • Glycoproteins / metabolism
  • Humans
  • Keratinocytes / metabolism
  • Membrane Glycoproteins / chemistry
  • Microscopy, Confocal
  • Models, Biological
  • Organelles / metabolism
  • Skin / metabolism
  • rab GTP-Binding Proteins / metabolism
  • rab GTP-Binding Proteins / physiology*
  • trans-Golgi Network / metabolism

Substances

  • Glucosylceramides
  • Glycoproteins
  • Membrane Glycoproteins
  • TGOLN2 protein, human
  • Cathepsin D
  • rab11 protein
  • rab GTP-Binding Proteins