Lysophosphatidic acid (LPA) phosphatase and nucleotidase; principle and physiological nucleotidase working on GMP, UMP, CMP and nicotinamide mononucleotide; role in LPA hydrolysis in response to phosphate (Pi) starvation and as part of the ribose salvage pathway; phosphatase activity is soluble and Mg2+ dependent; expression is induced by low Pi levels and by Pho85p inactivation; repressed by Gcn4p under normal conditions; PHM8 has a paralog, SDT1, that arose from the whole genome duplication