Binds to membranes enriched in phosphatidylserine or phosphatidylglycerol in a calcium-dependent manner. Half-maximal membrane binding requires about 60 uM calcium. Does not bind to membranes that lack phospholipids with an acidic headgroup. Monomer and homodimer. Myristoylation anchors the protein to the membrane, but the protein also displays calcium-dependent, reversible binding to lipid membranes. Detected on the tips of microvilli in small intestine (at protein level). A pair of annexin repeats may form one binding site for calcium and phospholipid. Belongs to the annexin family.