Annexins are a family of proteins that bind to phospholipids in the presence of calcium ions. They play a crucial role in various cellular processes, including membrane trafficking, cell signaling, and inflammation. By interacting with cell membranes, annexins help stabilize membrane structures and facilitate the transport of molecules. These proteins are found in many different organisms, from humans to plants and bacteria. Each annexin has a unique structure and function, but they all share a common ability to bind to membranes. Their diverse roles make them important for maintaining cellular health and responding to environmental changes.