Primer recognition proteins (PRP) are accessory proteins for DNA polymerase alpha in lagging strand DNA replication. We have previously reported that the PRP consist of a complex of two proteins identified as 3-phosphoglycerate kinase (PGK) and the protein-tyrosine kinase substrate, annexin 2 monomer. The physiological role of annexin 2 is not known. Two pools of annexin 2 exist in cells. A majority of annexin 2 is localized with the plasma membrane as a heterotetramer in association with a light chain. Monomer annexin 2 is cytosolic. The identification of annexin 2 monomer as a part of the PRP complex represents one of the physiological roles of this protein in cells. To function as PRP, annexin 2 and PGK would have to be present in the cell nucleus. To investigate whether monomer annexin 2 is indeed associated with nuclear DNA synthesis, we investigated the presence of annexin 2 and PGK in the cell nucleus. In this paper, we demonstrate the presence of annexin 2 and PGK in nuclear extracts. The nuclear fraction of these proteins represents a small subset of the total cellular pools. Immunoelectron-microscopic analyses using anti-PRP antisera demonstrate the distribution of these proteins in HeLa cell nuclei and cytoplasm. Under identical conditions, an anti-cytokeratin monoclonal antibody preferentially labels the plasma membrane without detectable intracellular staining. The distribution of annexin 2 and PGK in both nuclei and cytoplasm is similarly observed in cells from normal tissues such as freshly isolated rat hepatocytes and hamster pancreatic tissue.(ABSTRACT TRUNCATED AT 250 WORDS)