The N-Terminal Domain of Vimentin Alters Bladder Permeability

Abstract

We assessed the effect of the vimentin amino terminal polypeptide (NT1) on barrier function of rabbit bladder epithelium. The effect of NT1 on the properties of rabbit bladder epithelium were studied using Ussing chambers and electrophysiological methods. NT1 increased transepithelial conductance (Gt) in a voltage dependent manner. At a transepithelial voltage (Vt) of -70 mV (serosal solution ground) the addition of NT1 to mucosal solution did not result in a change in Gt. When Vt was clamped to 0 mV, there was a time dependent increase in Gt. The increase in Gt was reversed by clamping Vt back to -70 mV or by removing NT1 from the mucosal bath at 0 mV. The polypeptide acts primarily at the apical membrane with a conductance increase that is concentration dependent. Induced conductance is nonselective for small monovalent cations and anions. The ability of NT1 to increase membrane conductance was decreased in the presence of bath calcium. The data suggest that the amino terminus of vimentin can interact with the plasma membrane of bladder epithelium and increase ion permeability in a voltage dependent manner.