ANXA

ANXA refers to the annexin family of proteins, a group of calcium-dependent phospholipid-binding proteins. In humans, the ANXA gene family comprises ANXA1 through ANXA11. Annexins share a conserved C-terminal core domain made up of four annexin repeats that mediates calcium-dependent association with phospholipid membranes, while the N-terminal regions vary among isoforms and contribute to distinct functions.

Annexins participate in a range of cellular processes related to membrane dynamics and signaling. They are involved in membrane trafficking, vesicle exocytosis and endocytosis, membrane repair, and cytoskeletal interactions. Several members also contribute to inflammatory responses and coagulation; for example, ANXA1 has anti-inflammatory properties, and ANXA2 forms a heterotetramer with S100A10 that promotes plasminogen activation. ANXA5 binds phosphatidylserine, and its protein product is widely used as a marker in assays detecting apoptosis.

Expression and localization of annexins are broad and context-dependent. Most ANXA proteins are primarily cytosolic but translocate to membranes in response to elevated intracellular calcium. Some members associate with the cell surface or extracellular matrix. Subcellular localization and function can vary with cell type, developmental stage, and physiological conditions.

Clinical significance is noted for several ANXA proteins, with deregulation or mutations linked to cancer, inflammatory and autoimmune disorders, cardiovascular disease, and neurodegenerative conditions. ANXA5 is commonly used in research and diagnostics for apoptosis detection, while other family members are studied as potential therapeutic targets due to their roles in inflammation, coagulation, and cell signaling.