| Modification Notes |
The yeast plasma membrane H(+)-ATPase (Pma1) generates a membrane electrochemical gradient which is required for the secondary uptake of nutrients (1). Pma1, located in the yeast plasma membrane and encoded by the PMA1 gene, provides energy for the active transport of nutrients and regulates intracellular pH (2). The function of the PMA1 gene is essential for cell growth and development because a null mutation is lethal in haploid cells (2,4). Pma1 is delivered to the cell surface via the secretory pathway (3). Pma1 is post-translationally regulated in response to the availability of glucose (1). PTK2 and HRK1 (YOR267c), encode protein kinases implicated in activation of Pma1 in response to glucose metabolism (5). The strong homology between the amino-acid sequence of Pma1 and those of, Na+-, K+- and Ca2+- ATPases is consistent with the notion that the family of cation pumps which form a phosphorylated intermediate evolved from a common ancestral ATPase (4). The gene which encodes Pma1 maps to chromosome VII (4). |