Annexins VII and XI are present in a human macrophage-like cell line. Differential translocation on FcR-mediated phagocytosis

We have studied the divalent cation-dependent association of proteins to su bcellular fractions of human macrophage-like cells before and after FcR-med iated phagocytosis, Among these proteins we have identified annexins VII an d XI for the first time in these cells, along with annexins I, III, and VI, Although all of these annexins are present in the cytosolic fraction, the extent of their association to membrane and phagosome fractions from restin g and stimulated cells is variable, Annexin VII translocates from cytosolic to membrane fractions after phagocytic stimulation, along with annexin I, III, and VI, Annexins VII and XI are found associated with purified phagoso mes along with I, III, and VI, and this association is greater after a 24-h chase period. Our results show differences in the intracellular distributi on of different annexins in macrophage-like cells on phagocytosis. Annexins VII, VI, III, and I respond to particle ingestion by translocating to phag osomes and other cell membrane structures, whereas annexin XI translocates predominantly to phagosomes, suggesting dissimilarities in their function.