The nuclear location of annexin V in the human osteosarcoma cell line MG-63 depends on serum factors and tyrosine kinase signaling pathways

Serum starvation of MG-63 cells increases their doubling time from 24 h to 4 days, Cells grown in medium containing 10% fetal calf serum contain high levels of annexin V in the cell nucleus, whereas growth for 4 days in the absence of serum results in loss of nuclear annexin V from 72 +/- 4% of cells, Many of the cells which still have nuclear annexin V under these conditions seem to have recently finished dividing, Refeeding cells with medium containing serum restores annexin V to nuclei within 5 h, Charcoal treatment removes factors from serum that are required to allow annexin V to return to the nucleus, Protein synthesis is not required for annexin V to return to nuclei since inhibition of protein synthesis with cycloheximide does not prevent the serum-induced return of annexin V to nuclei, This, and other evidence, indicates that the presence of annexin V in nuclei reflects translocation rather than catabolism and resynthesis. Inhibition of tyrosine kinase activities with genistein attenuates the relocation of annexin V from the cytoplasm to the nucleus, Thus, the nuclear location of annexin V is controlled by signaling pathways involving serum factors and tyrosine kinases, The results argue for an important role for annexin V in the cell nucleus. (C) 1997 Academic Press.