. 1997 Dec 1;110(6):727–740. doi: 10.1085/jgp.110.6.727

Table I.

Comparative Effects of Metal Ions on the Dynamics of TJs, as Observed in the Present Study, and on the Uvomorulin Molecule (Hyafil et al., 1981)

TJs		Uvomorulin
• Ca²⁺, Mn²⁺, and Cd²⁺ confer stability to the TJs, but not to Mg²⁺ or Ba²⁺.		• Ca²⁺, Mn²⁺, and Cd²⁺ confer trypsin resistance to Umt (an 84-kD fragment of uvomorulin) and trigger the recognition of Umt by a monoclonal antibody. Mg²⁺ and Ba²⁺ are ineffective.
• Ca²⁺ and Mn²⁺ are able to trigger the resealing of TJs previously opened by Ca²⁺ removal. Cd²⁺ is ineffective and apparently has a toxic effect upon the epithelial cells. Mg²⁺ and Ba²⁺ were ineffective.		• Ca²⁺ and Mn²⁺ (but not Cd²⁺, which is toxic to cells) prevent EC cells or morulae from decompacting in Ca²⁺-free medium. Mg²⁺ and Ba²⁺ were ineffective.
• La³⁺ did not confer stability to the TJs. In addition, La³⁺ in the presence of Ca²⁺ reverts the Ca²⁺-dependent stability of the TJs, thus behaving as an inhibitor of the Ca²⁺ action.		• La³⁺ did not protect Umt against trypsin digestion. In addition, La³⁺ in the presence of Ca²⁺ reverts the Ca²⁺-induced protection, thus behaving as an inhibitor of Ca²⁺ action.
• The inhibitory action of La³⁺ upon the Ca²⁺ effect is reversible upon La³⁺ removal.		• The inhibitory action of La³⁺ upon the Ca²⁺ effect is reversible upon La³⁺ removal.