AQP4 Protein, Human (His)

AQP4, a water-specific channel, is instrumental in maintaining brain water homeostasis and facilitating glymphatic solute transport. It plays a crucial role in regulating the exchange of water across the blood-brain interface, influencing cerebrospinal fluid influx into the brain cortex and parenchyma through paravascular spaces surrounding penetrating arteries. Additionally, AQP4 is essential for the proper drainage of interstitial fluid along paravenous pathways, contributing to the normal clearance of solutes, including soluble beta-amyloid peptides derived from APP, from the brain interstitial fluid. While redundant in urinary water homeostasis and concentrating ability, AQP4 forms homotetramers, with the tetramers capable of organizing into oligomeric arrays of varying sizes in membranes. This oligomerization can facilitate cell-cell adhesion through interactions between AQP4 arrays in adjacent cells. AQP4 is also part of a complex involving MLC1, TRPV4, HEPACAM, and ATP1B1, highlighting its role within a larger molecular network.