HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ireland, M. E. Articles by Mrock, L. K. Search for Related Content PubMed PubMed Citation Articles by Ireland, M. E. Articles by Mrock, L. K.

Differentiation of Chick Lens Epithelial Cells: Involvement of the Epidermal Growth Factor Receptor and Endogenous Ligand

From the Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, Michigan.

PURPOSE. To characterize the constitutively activated epidermal growth factor receptor in a lens epithelial cell population experiencing initial stages of lens fiber formation, the chick lens annular pad.

METHODS. Phosphotyrosine levels of the receptor were examined with western blot analysis and immunoprecipitation after ligand stimulation. Endogenous receptor ligands were immunologically identified in whole cell lysates of freshly isolated cells. The expression of lens fiber–specific differentiation marker proteins was examined with western blot analysis and enzyme-linked immunosorbent assay (ELISA) in short-term primary cultures of annular pad cells exposed to ligand.

RESULTS. The major phosphotyrosine-containing protein in annular pad cells comigrated with the epidermal growth factor receptor and increased its phosphotyrosine content after epidermal growth factor treatment. Both time- and dose-dependent responses were noted. The constitutive activation of the receptor was determined in the presence of phosphatase inhibitors. Endogenous transforming growth factor-, but not epidermal growth factor, was detected in freshly isolated cells. Transforming growth factor- (TGF-) treatment produced greater increases in receptor phosphotyrosine levels than equimolar levels of epidermal growth factor. Finally, TGF- treatment induced increased expression of the beaded filament protein filensin when compared with control cells. Filensin expression was increased further when cells were costimulated with TGF- and cAMP analogs.

CONCLUSIONS. At least in the postnatal lens, endogenous TGF- may affect overall growth patterns by modulating differentiation-specific protein expression. Furthermore, signaling pathways elicited by TGF- and cAMP analogs converge to cooperatively enhance lens fiber differentiation.

This article has been cited by other articles:

				G. Chandrasekher and D. Sailaja Differential Activation of Phosphatidylinositol 3-Kinase Signaling during Proliferation and Differentiation of Lens Epithelial Cells Invest. Ophthalmol. Vis. Sci., October 1, 2003; 44(10): 4400 - 4411. [Abstract] [Full Text] [PDF]

				D. J. Collison and G. Duncan Regional Differences in Functional Receptor Distribution and Calcium Mobilization in the Intact Human Lens Invest. Ophthalmol. Vis. Sci., September 1, 2001; 42(10): 2355 - 2363. [Abstract] [Full Text] [PDF]