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.
Mohiti
J
J
Department of Biochemistry and Molecular Biology, University of Leeds, United Kingdom.
Caswell
A M
AM
Walker
J H
JH
D017304:Annexin A5 / Q000032:analysis* / Q000096:biosynthesis / Q000502:physiology; D001798:Blood Proteins / Q000494:pharmacology*; D016723:Bone Remodeling / Q000502:physiology; D002455:Cell Division / Q000502:physiology; D002467:Cell Nucleus / Q000737:chemistry / Q000378:metabolism; D002606:Charcoal / Q000494:pharmacology; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D005312:Fetal Blood; D006801:Humans; D012516:Osteosarcoma; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D014407:Tumor Cells, Cultured / Q000166:cytology / Q000187:drug effects / Q000201:enzymology
D017304:Annexin A5; D001798:Blood Proteins; D016895:Culture Media, Serum-Free; D002606:Charcoal; D011505:Protein-Tyrosine Kinases