Calcium-binding protein that plays a role in various cellular processes including motility, angiogenesis, cell differentiation, apoptosis, and autophagy. Increases cell motility and invasiveness by interacting with non-muscle myosin heavy chain (NMMHC) IIA/MYH9 (By similarity). Mechanistically, promotes filament depolymerization and increases the amount of soluble myosin-IIA, resulting in the formation of stable protrusions facilitating chemotaxis (By similarity). Modulates also the pro-apoptotic function of TP53 by binding to its C-terminal transactivation domain within the nucleus and reducing its protein levels (By similarity). Within the extracellular space, stimulates cytokine production including granulocyte colony-stimulating factor and CCL24 from T-lymphocytes (By similarity). In addition, stimulates T-lymphocyte chemotaxis by acting as a chemoattractant complex with PGLYRP1 that promotes lymphocyte migration via CCR5 and CXCR3 receptors (By similarity). Homodimer. Interacts with PPFIBP1 in a calcium-dependent mode. Interacts with PGLYRP1; this complex acts as a chemoattractant that promotes lymphocyte movement. Interacts with MYH9; this interaction increases cell motility. Interacts with Annexin 2/ANXA2. Interacts with TP53; this interaction promotes TP53 degradation. Interacts with CCR5 and CXCR3. Interacts with FCGR3A; this interaction inhibits PKC-dependent phosphorylation of FCGR3A. By nerve growth factor. Belongs to the S-100 family.