Location of phosphoglycerate mutase in rat skeletal muscle. An immunocytochemical and biochemical study.

The subcellular distribution of phosphoglycerate mutase was studied by immunogold techniques. With the aid of highly affinity-purified anti-phosphoglycerate mutase antibodies, the enzyme was found in both cytosol and nucleus of rat skeletal muscle. No evidence of interaction with contractile proteins was observed in cytosol. Nuclear location was also confirmed biochemically using purified nuclear preparations from rat skeletal muscle. Only one immunoreactive nuclear band was observed by Western blot experiments and corresponded to that of phosphoglycerate mutase mobility. Activity measurements from nuclear extracts showed that 25% of total specific activity is found in the nuclei.