Stabilization of intercellular contacts in MDCK cells during Ca2+ deprivation. Selective effects of monocarboxylic acids on desmosomes.

Short-chain monocarboxylic acids (MCAs) selectively protect desmosomal junctions of MDCK cells from disruption by chelating agents and low calcium medium. This effect occurs in the millimolar concentration range and increases inversely with carbon chain length (formate > acetate = propionate > butyrate > isobutyrate > isovalerate). The relative activity of MCAs does not correlate with their overall hydrophobicity or ability to chelate ions, or their effectiveness in lowering cytosolic pH. It exhibits chemical specificity and is dependent upon postconfluency culture age. MCAs also inhibit cell rounding produced by low concentrations of aminocarboxylate-chelating agents. Their effect on cell rounding, but not on desmosomes, can be antagonized by okadaic acid. The possibility is discussed that MCAs may produce their effects by binding specifically to protein(s) associated with the desmosome of mature, fully polarized MDCK monolayers.