AQP4(Aquaporin 4) is a member of the aquaporin family of intrinsic membrane proteins that function as water-selective channels in the plasma membranes of many cells. AQP4 plays a crucial role in regulating water homeostasis in the body, particularly in the central nervous system and skeletal muscle. AQP4 is predominantly localized to the sarcolemma of fast-twitch muscle fibers, where AQP4 facilitates rapid water transport, essential for muscle contraction and recovery. AQP4 presence in the brain is vital for maintaining water balance in the extracellular space, which is critical for neuronal function and overall brain health. AQP4 dysregulation has been implicated in various neurological disorders, making AQP4 a significant target for research in understanding and treating conditions such as edema and multiple sclerosis.