Catalyzes the reversible ATP-dependent phosphorylation of mevalonate 5-phosphate to produce mevalonate diphosphate and ADP, a key step in the mevalonic acid mediated biosynthesis of isopentenyl diphosphate and other polyisoprenoid metabolites. (R)-5-phosphomevalonate + ATP = (R)-5-diphosphomevalonate + ADP Isoprenoid biosynthesis; isopentenyl diphosphate biosynthesis via mevalonate pathway; isopentenyl diphosphate from (R)-mevalonate: step 2/3. Monomer. Was originally thought to be located in the peroxisome. However, was later shown to be cytosolic.