This chapter reviews the molecular genetics of yeast ion transport. The H+-ATPase is the principal electrogenic ion pump in the plasma membranes of fungi. The electrochemical energy of this gradient drives the import of nutrients and other ions. Besides providing the energy for nutrient uptake, the proton pump also controls the intracellular pH. Through the electrogenic pumping of protons, the plasma membrane ATPase plays both regulatory and energetic roles in yeast cell biology. The transmembrane domains of the H+-ATPase serve two primary functions: (1) they anchor the transporters to the plasma membrane and (2) they form the polar pathway that protons take in their journey across the membrane. Several of the more highly conserved amino acids located within the putative transmembrane domains of the pump have been mutationally altered to assess their roles in proton transport. Pro 335 is completely conserved among all of the P-type ATPases and resides in the middle of the transmembrane segment that itself is the most highly conserved among these ion pumps.
ASJC Scopus subject areas
- Cell Biology