Regulation of lens cell-to-cell communication by activation of PKCgamma and disassembly of Cx50 channels.

摘要: PURPOSE. Lens fiber gap junctions comprise approximately equal molar amounts of connexin46 (Cx46) and connexin50 (Cx50), both which contribute significantly to coupling in the lens cortex nucleus. The current study was conducted test hypothesis that regulation by activation protein kinase C (PKC) affects number channels composed Cx46, Cx50, or connexins. METHODS. Whole rat lenses were treated with phorbol-12-myristate-13-acetate (TPA) activate PKC inactive analogue 4-phorbol,12,13-didecaneote (PDD) as a control. superficial cortical fibers studied morphologically quantitative freeze-fracture immunolabeling (FRIL); functionally Lucifer yellow dye transfer assay; chemically measuring activity, connexin phosphorylation coimmunoprecipitation. RESULTS. Treatment TPA activated uncoupled 60%. PDD had no effect. Activation decreased density Cx50 assembled junctions, increased hemichannels plasma membrane induced circular voids 22 300 nm diameter within remaining plaques. Coimmunoprecipitation studies indicated soluble translocated into fractions contained lipid raft marker caveolin (Cav)-1. In environment, phosphorylated at serines threonines Cx46 only threonines. CONCLUSIONS. provide experimental support for comprising mixtures malleable communicating pathways between nucleus metabolically active surface. findings also suggest channel disassembly occurs distinct microdomains. (Invest Ophthalmol Vis Sci. 2005;46:3247‐3255) DOI:10.1167/ iovs.04-1504