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Regulation of protein phosphorylation of the intermediate-sized filament vimentin in the ciliary epithelium of the mammalian eye

Journal Article · · J. Biol. Chem.; (United States)
OSTI ID:6335830
The intermediate-sized filaments of vimentin-type (Mr = 57,000) have been identified biochemically and immunochemically as a major cytoskeleton component in the ciliary epithelium of the mammalian eye. When human or rabbit ciliary processes, or cultured ciliary epithelial-derived cells were incubated in serum-free medium containing (TSP)orthophosphate and any of the following agents: 1) beta-adrenergic agonists (isoproterenol or epinephrine), 2) direct activators of adenylate cyclase (cholera toxin or forskolin), 3) analogs of cyclic AMP (8-Br-cAMP), or 4) prostaglandin E1, the phosphorylation of vimentin was significantly enhanced. The maximal enhancement ranged, in vivo and in vitro, from about 3-fold in human to 5-fold in rabbit, with either 1 mM 8-Br-cAMP or 0.1 microM forskolin. Indirect immunofluorescence microscopy using a monoclonal antibody, anti-vimentin, allowed the localization of vimentin filaments in cultured ciliary epithelial cells. Treatment of these cells in culture with the catecholamine hormone, isoproterenol (1 microM), resulted in a profound reorganization of vimentin filaments. This may be correlated with the enhanced levels of phosphorylated vimentin observed upon increasing cellular cyclic AMP.
Research Organization:
Yale Univ. School of Medicine, New Haven, CT
OSTI ID:
6335830
Journal Information:
J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 18; ISSN JBCHA
Country of Publication:
United States
Language:
English