Induction of epithelial tight junctions by a light chain protein isolated from a patient with Fanconi's syndrome.
Tight junctions have not been described in the adult human glomerulus. In a 22-year-old patient with kappa light chain proteinuria, tight junctions were observed between glomerular epithelial cell foot processes (kidney biopsy). The light chain isolated from urine proved to have a relatively high isoelectric point. When the light chain was exposed in vitro to the mucosal surface of a 'leaky' epithelium, the Necturus gallbladder, transepithelial resistance and potential difference increased in a concentration-dependent, reversible manner and NaCl dilution potentials decreased, consistent with a reduction in tight-junctional ionic permeability. Gallbladders fixed in situ and freeze-fractured during peak electrophysiological responses revealed an increase in tight-junctional depth. This report indicates that certain light chains, possibly by virtue of a positive charge, may induce changes in epithelial tight junction structure and/or permeability.
D000328:Adult; D000818:Animals; D001681:Biological Assay; D004594:Electrophysiology; D004848:Epithelium / Q000473:pathology / Q000502:physiology; D005198:Fanconi Syndrome / Q000276:immunology* / Q000473:pathology; D005614:Freeze Fracturing; D005704:Gallbladder / Q000502:physiology; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000652:urine*; D007145:Immunoglobulin kappa-Chains / Q000502:physiology / Q000652:urine*; D007678:Kidney Glomerulus / Q000473:pathology*; D008297:Male; D008854:Microscopy, Electron; D009337:Necturus
D007147:Immunoglobulin Light Chains; D007145:Immunoglobulin kappa-Chains