NUCLEAR LOCATION OF PHOSPHOGLYCERATE MUTASE BB ISOZYME IN RAT-TISSUES

We have previously reported (Urena et al. Eur. J. Cell Biol. 1990) tha t in skeletal muscle, type MM phosphoglycerate mutase isozyme is prese nt in the nucleus as well as in the cytosol. To determine whether type BB phosphoglycerate muttase isozyme is also present in nucleus, the s ubcellular location of this isozyme was studied in different rat tissu es by cell fractionation and immunogold techniques. With the aid of hi gh affinity-purified anti-phosphoglycerate mutase BB isozyme antibodie s, the isozyme was located in the nucleus of neuronal, astroglial and liver cells but not in the nucleus of oligodendroglial and endothelial cells. Biochemical studies on purified nuclear fractions also demonst rated the presence of phosphoglycerate mutase activity in the nucleus. Both immunocytochemical and biochemical techniques showed that nuclea r phosphoglycerate mutase-specific activity depended on the type of ce ll.