5 research outputs found
Biochemical and biophysical analyses of tight junction permeability made of claudin-16 and claudin-19 dimerization
The molecular nature of tight junction architecture and permeability is a long-standing mystery. Here, by comprehensive biochemical, biophysical, genetic, and electron microscopic analyses of claudin-16 and -19 interactions—two claudins that play key polygenic roles in fatal human renal disease, FHHNC—we found that 1) claudin-16 and -19 form a stable dimer through cis association of transmembrane domains 3 and 4; 2) mutations disrupting the claudin-16 and -19 cis interaction increase tight junction ultrastructural complexity but reduce tight junction permeability; and 3) no claudin hemichannel or heterotypic channel made of claudin-16 and -19 trans interaction can exist. These principles can be used to artificially alter tight junction permeabilities in various epithelia by manipulating selective claudin interactions. Our study also emphasizes the use of a novel recording approach based on scanning ion conductance microscopy to resolve tight junction permeabilities with submicrometer precision
Inducible Expression of Claudin-1 in Glomerular Podocytes Generates Aberrant Tight Junctions and Proteinuria through Slit Diaphragm Destabilization
Capturing Rare Conductance in Epithelia with Potentiometric-Scanning Ion Conductance Microscopy
Tight
junctions (TJs) are barrier forming structures of epithelia
and can be described as tightly sealed intercellular spaces. Transport
properties have been extensively studied for bicellular TJs (bTJs).
Knowledge of the barrier functions of tricellular junctions (tTJs)
are less well understood, due largely to a lack of proper techniques
to locally measure discrete tTJ properties within a much larger area
of epithelium. In this study, we use a nanoscale pipet to precisely
locate tTJs within epithelia and measure the apparent local conductance
of tTJs with a technique termed potentiometric scanning ion conductance
microscopy (P-SICM). P-SICM shows the ability to differentiate transport
through tTJs and bTJs, which was not possible with previous techniques
and assays. We describe P-SICM investigations of both wild type and
tricellulin overexpression Madin-Darby Canine Kidney (strain II, MDCKII)
cells