Reviewed here is the current knowledge of proton transport mechanisms in mammals. The emphasis is on gastric acid secretion and the role of the H+, K+-ATPase, but molecular and cellular information on other P-, V- and F-type H+-ATPases, in bone, kidney, plants and yeast, as well as other cation ATPases, are included for important comparisons. The role of proton/anion antiports, symports and channels in proton transport is discussed. Further attention is given to the regulation of proton transport mechanisms and cellular mechanisms to resist damage from highly acidic environments.Proceedings of the NATO Advanced Research Workshop on Molecular and Cellular Mechanisms of H+ Transport, held in York, U.K., July 27 to August 1, 1993Reviewed here is the current knowledge of proton transport mechanisms in mammals. The emphasis is on gastric acid secretion and the role of the H+, K+-ATPase, but molecular and cellular information on other P-, V- and F-type H+-ATPases, in bone, kidney, plants and yeast, as well as other cation ATPases, are included for important comparisons. The role of proton/anion antiports, symports and channels in proton transport is discussed. Further attention is given to the regulation of proton transport mechanisms and cellular mechanisms to resist damage from highly acidic environments.Gastric H+,K+-ATPase.- Gene Structure and Regulation of Gastric Proton Pump.- The Gastric H/K ATPase ? Subunit Gene and Transcriptional Pathways in Acid-Secreting Epithelia of the Stomach and Kidney.- Functional Expression of Gastric H,K-ATPase in Sf9 Cells Using the Baeulovirus Expression System.- Structural and Functional Integrity of H,K-ATPase Depends on Its ?-Subunit.- The Topology of the ?, ? Subunits of the Gastric H/K ATPase.- Synthetic Peptide Antibody Probes of Membrane Orientation of the Gastric H,K-ATPase.- Molecular Determinants of Subunit Assembly and Processing in Na,K-ATPase and H,K-ATPase.- Assembly of Hybrid Pumps from Na,K-ATPase ? Subunits and the H,lS“