ASSOCIATION OF TRANSGLUTAMINASE WITH THE RECONSTITUTED KERATIN FILAMENTS ISOLATED FROM RAT VAGINAL EPITHELIAL-CELLS

We report a novel association of the calcium dependent cross-linking e nzyme, transglutaminase (TGase) with the urea soluble reconstituted ke ratin filaments (RKF) isolated from the rat vaginal epithelial cells ( VEC). This was ascertained by measuring the activity using C-14-spermi dine incorporation and also by an increase in keratin filament aggrega tion by the addition of only TGase cofactor-calcium. These events were specifically inhibited by the treatment of calcium chelator, EDTA at a concentration >2 mM as well as by pretreating the RKF with histamine , a TGase substrate inhibitor. The association was also exemplified by immunoblotting analysis where a specific and preferential polypeptide of molecular weight 58 kDa cross-reacted with TGase antibody amongst the other keratins. This phenomenon was not seen in the keratins isola ted from skin, a non-targeting tissue for estradiol action.