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

Danielle M. Robertson, Meifang Zhu, Yu Chieh Wu

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

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.

Original languageEnglish (US)
Pages (from-to)179-186
Number of pages8
JournalExperimental Eye Research
Volume94
Issue number1
DOIs
StatePublished - Jan 2012

Fingerprint

Cadherins
Epithelial Cells
Insulin-Like Growth Factor I
Immunoprecipitation
Fluorescent Antibody Technique
Western Blotting
Ligands
Cell Line
Telomerase
Golgi Apparatus
Endocytosis
Chromatin
Intercellular Signaling Peptides and Proteins
Phosphorylation
Cell Membrane

Keywords

  • Cornea
  • E-cadherin
  • Epithelium
  • IGF-1R

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

Cite this

Cellular distribution of the IGF-1R in corneal epithelial cells. / Robertson, Danielle M.; Zhu, Meifang; Wu, Yu Chieh.

In: Experimental Eye Research, Vol. 94, No. 1, 01.2012, p. 179-186.

Research output: Contribution to journalArticle

Robertson, Danielle M. ; Zhu, Meifang ; Wu, Yu Chieh. / Cellular distribution of the IGF-1R in corneal epithelial cells. In: Experimental Eye Research. 2012 ; Vol. 94, No. 1. pp. 179-186.
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