A high phosphotyrosine phosphatase activity is present in differentiating bovine lens cells.
Activity of phosphotyrosine-protein phosphatases (PTPases) has been investigated in the different cellular regions of bovine eye lens. PTPases were tested in cellular detergent extracts using phospholabelled synthetic peptides and p-nitrophenyl phosphate. We show that a high PTPase activity is only present in cells which undergo differentiation, namely the equatorial epithelium and cortex fiber cells. Since this activity is found to be severely inhibited by a specific inhibitor of receptor-type PTPases, it can be suggested that one or more members of this class of PTPases might play an important role in the lens differentiation process.
Blanquet
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PR
Unité de Recherches Gérontologiques, INSERM U118, Paris, France.
Croquet
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F
D000818:Animals; D002417:Cattle; D002454:Cell Differentiation / Q000502:physiology*; D004848:Epithelium / Q000201:enzymology; D007904:Lens Cortex, Crystalline / Q000201:enzymology; D007908:Lens, Crystalline / Q000166:cytology* / Q000201:enzymology*; D010766:Phosphorylation; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism*
D017027:Protein Tyrosine Phosphatases