ABSTRACT
Lens fiber cells are coupled by communicating junctions, which are thought to be comprised of four identical subunits of molecular weight 26 kDa. These junctions are presumably involved in nutrient and waste flux and help to maintain normal levels of ions in this specialized avascular organ. However, in 1985 S. J. Girsch and C. Peracchia reported the development of a method for reconstitution and assay of the lens junctional protein in artificial membranes. This method is based on detection of liposome swelling in the presence of low molecular weight compounds such as sucrose describe for the reconstitution of bacterial outer membrane proteins. The assay for permeability of membranes containing reconstituted major intrinsic polypeptide (MIP26K) depended upon the ability of ascorbate but not larger reductants to pass through the channel and reduce cytochrome C which had trapped inside the liposome.
