Cellular distribution of the IGF-1R in corneal epithelial cells

Exp Eye Res. 2012 Jan;94(1):179-86. doi: 10.1016/j.exer.2011.12.006. Epub 2011 Dec 13.


This study characterized the expression and subcellular localization of the IGF-1R in human corneal epithelial cells. Using a human telomerase-immortalized corneal epithelial cell line, IGF-1R expression and localization was assayed by immunofluorescence and subcellular fractionation followed by western blot. IGF-1R expression was confirmed in primary cultured human corneal epithelial cells. Nuclear localization was assessed under basal and IGF-1 stimulated culture conditions; phosphorylation status of the receptor in response to IGF-1 was demonstrated by western blot. IGF-1R:E-cadherin interactions were detected by immunofluorescence and co-immunoprecipitation of whole cell lysates. The results of this study demonstrated that IGF-1R localized predominantly to the nucleus and in a perinuclear cap pattern which co-localized with the Golgi complex in proliferating corneal epithelial cells. There was no difference in nuclear localization between primary or telomerized cell lines. Subcellular fractionation confirmed IGF-1Rα- and β-subunit localization in soluble and chromatin-bound nuclear fractions. Neither growth factor withdrawal nor IGF-1 stimulation altered nuclear IGF-1R. At points of cell-cell contact, IGF-1R co-localized with E-cadherin; co- immunoprecipitation assays confirmed the presence of an IGF-1R:E-cadherin complex. Importantly, this is the first report to identify IGF-1R in the nucleus and complexed with E-cadherin at points of cell-cell contact in corneal epithelial cells. Nuclear trafficking appeared to be independent of ligand-mediated events at the plasma membrane. The identification of IGF-1R in the nucleus and complexed with E-cadherin suggests novel regulatory functions outside the canonical ligand-induced endocytosis signaling pathway.

Publication types

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

MeSH terms

  • Blotting, Western
  • Cadherins / metabolism
  • Cell Line
  • Cell Nucleus / metabolism*
  • Electrophoresis, Polyacrylamide Gel
  • Epithelial Cells / metabolism
  • Epithelium, Corneal / metabolism*
  • Fluorescent Antibody Technique, Indirect
  • Humans
  • Phosphorylation
  • Receptor, IGF Type 1 / metabolism*


  • Cadherins
  • Receptor, IGF Type 1