Tyrosine phosphorylation in desmosomes and hemidesmosomes of the corneal epithelium.
We examined the localization of phosphotyrosine (p-Tyr)-modified proteins in the normal corneal epithelium using affinity-purified rabbit anti-p-Tyr antibody. Normal rat cornea was fixed and semi-thin and ultra-thin frozen sections were prepared. Immunofluorescence microscopy showed that p-Tyr was distributed along the cell membrane of the corneal epithelium. Immunogold electron microscopy revealed that the labeling is exclusively localized in the desmosomes and hemidesmosomes. A fraction enriched with desmosomes was extracted from the bovine corneal epithelium and examined by Western blotting. Immunoblotting for p-Tyr showed eight prominent bands (290, 200, 190, 115, 85, 62, 50, and 47 kD) in the desmosomal fraction. The enrichment of p-Tyr in desmosomes and hemidesmosomes of the corneal epithelium suggests that these cell-to-cell and cell-to-substrate junctions are involved in signal transduction.
Department of Ophthalmology, Faculty of Medicine, Kyoto University, Japan.
K
K
Amino
M
M
Takahashi
Y
Y
Honda
T
T
Fujimoto
D000818:Animals; D002417:Cattle; D003315:Cornea / Q000737:chemistry*; D003896:Desmosomes / Q000737:chemistry* / Q000648:ultrastructure; D004848:Epithelium / Q000737:chemistry; D015151:Immunoblotting; D008856:Microscopy, Fluorescence; D016253:Microscopy, Immunoelectron; D010766:Phosphorylation; D011817:Rabbits; D051381:Rats; D017208:Rats, Wistar; D014443:Tyrosine / Q000378:metabolism*
D014443:Tyrosine