Plays important roles in the innate immune response as effector of glucocorticoid-mediated responses and regulator of the inflammatory process. Has anti-inflammatory activity. Plays a role in glucocorticoid-mediated down-regulation of the early phase of the inflammatory response. Contributes to the adaptive immune response by enhancing signaling cascades that are triggered by T-cell activation, regulates differentiation and proliferation of activated T-cells. Promotes the differentiation of T-cells into Th1 cells and negatively regulates differentiation into Th2 cells (By similarity). Has no effect on unstimulated T-cells. Negatively regulates hormone exocytosis via activation ofthe formyl peptide receptors and reorganization of the actin cytoskeleton (By similarity). Has high affinity for Ca(2+) and can bind up to eight Ca(2+) ions (By similarity). Displays Ca(2+)-dependent binding to phospholipid membranes (By similarity). Plays a role in the formation of phagocytic cups and phagosomes. Plays a role in phagocytosis by mediating the Ca(2+)-dependent interaction between phagosomes and the actin cytoskeleton (By similarity). Functions at least in part by activating the formyl peptide receptors and downstream signaling cascades. Promotes chemotaxis of granulocytes and monocytes via activation of the formyl peptide receptors. Promotes rearrangement of the actin cytoskeleton, cell polarization and cell migration. Promotes resolution of inflammation and wound healing. Acts via neutrophil N-formyl peptide receptors to enhance the release of CXCL2. Homodimer; non-covalently linked (By similarity). Homodimer; linked by transglutamylation. Homodimers linked by transglutamylation are observed in placenta, but not in other tissues. Interacts with S100A11. Heterotetramer, formed by two molecules each of S100A11 and ANXA1 (By similarity). Interacts with DYSF (By similarity). Interacts with EGFR (By similarity). Colocalizes with actin fibers at phagocytic cups. Secreted, at least in part via exosomes and other secretory vesicles. Detected in exosomes and other extracellular vesicles. Secretion is increased in response to wounding and inflammation (By similarity). Alternatively, the secretion is dependent on protein unfolding and facilitated by the cargo receptor TMED10; it results in the protein translocation from the cytoplasm into ERGIC (endoplasmic reticulum-Golgi intermediate compartment) followed by vesicle entry and secretion (By similarity). Detected in gelatinase granules in resting neutrophils. Neutrophil adhesion to endothelial cells stimulates secretion via gelatinase granules, but foreign particle phagocytosis has no effect. Displays calcium-dependent binding to phospholipid membranes (By similarity). In the lung, expressed in the ciliated cells of the tracheal endothelium, but not in the goblet cells. Expressed in type II pneumocytes and alveolar macrophages. The full-length protein can bind eight Ca(2+) ions via the annexin repeats. Calcium binding causes a major conformation change that modifies dimer contacts and leads to surface exposure of the N-terminal phosphorylation sites; in the absence of Ca(2+), these sites are buried in the interior of the protein core. The N-terminal region becomes disordered in response to calcium-binding. Phosphorylated by protein kinase C, EGFR and TRPM7. Phosphorylated in response to EGF treatment. Sumoylated. Proteolytically cleaved by cathepsin CTSG to release the active N-terminal peptide Ac2-26. Was originally identified as calcium and phospholipid binding protein that displays Ca(2+)-dependent binding to phospholipid membranes and can promote membrane aggregation in vitro. Was initially identified as inhibitor of phospholipase A2 activity (in vitro). Inhibition of phospholipase activity is mediated via its phospholipid binding activity that limits the access of phospholipase to its substrates. Belongs to the annexin family.