Plasma membrane proton pumps in plants and fungi

• Published in: Bioscience Vol. 35; no. 1; pp. 34 - 37
• Main Author: Slayman, C.L
• Format: Journal Article
• Language: English
• Published: American Institute of Biological Sciences 1985; University of California Press
• Subjects: Acid-base imbalance; Acid-base imbalances; Adenosine triphosphatase; Adenosine triphosphatases; adenosinetriphosphatase; Animal cells; ATPases; Cell membranes; Cells (Biology); Enzymes; Eukaryotes; Eukaryotic cells; Fungi; Ions; Membrane potential; Physiological aspects; Plant physiology; Plants; plasma membrane; Plasma membranes; proton pump; Proton pumps; Protons; Pumps
• ISSN: 0006-3568; 1525-3244
• DOI: 10.2307/1310081

In the plasma membranes of eukaryotic cells, ATP-dependent ion pumps have evolved that are at once structurally simpler than the redox pumps or ATP-synthetases of bacterial and organellar membranes and energetically more efficient than the light-activated proton pump of halobacteria. These eukaryotic pumps are specialized in two important ways: As a class, they function strictly as pumps, not as ATP-synthetases; individually, they display strong substrate specificity, pumping sodium ions or calcium ions or protons. With only a few exceptions, proton pumps alone appear to be present in plant and fungal plasma membranes. These pumps sustain an inwardly directed proton motive force, which provides both the background for regulating cytoplasmic pH and the energy supply for a wide range of secondary active transport processes.