Subcellular localization of annexin V in human foreskin fibroblasts: nuclear localization depends on growth state.

Annexin V is a major intracellular calcium-binding protein in human foreskin fibroblasts. Immunocytochemistry revealed that annexin V was localized in the nucleus and throughout the cytoplasm in human foreskin fibroblasts. The presence of annexin V in the nucleus was variable depending on the growth state. Nuclear staining was strongest in proliferating cells immediately after sub-culture, and decreased on prolonged culture without changing the culture medium. The cytoplasmic location of annexin V was not greatly affected by the same conditions. Refeeding cells with fresh serum restored annexin V to the nuclei of all cells within 24 h indicating that nuclear localization of annexin V is dependent on serum factors.