Water Channel AQP4 MAQP4 Mercurial Insensitive Cell Free Protein

We offer Aquaporin 4, mAQP4, Mercurial insensitive water channel protein, cell-free protein isolated by nanodiscs, based on E.coli lysates for cell-free expression.

Our cell-free protein has been Function verificated.

Introduction

Aquaporin-4, also known as AQP4, is a water channel protein encoded by the AQP4 gene in humans. AQP4 belongs to the aquaporin family of integral membrane proteins that conduct water through the cell membrane. A limited number of aquaporins are found within the central nervous system (CNS): AQP1, 3, 4, 5, 8, 9, and 11, but more exclusive representation of AQP1, 4, and 9 are found in the brain and spinal cord.In the CNS, AQP4 is the most prevalent aquaporin channel, specifically located at the perimicrovessel astrocyte foot processes, glia limitans, and ependyma.

Function

Aquaporin-4’s overall function is to provide fast water transportation as well as maintain homeostatic balance within the central nervous system. It is the primary water channel protein that reconciles the homeostasis of water in the CNS. AQP4 may be involved in a variety of physiological processes such as waste removal (glymphatic system) and fine-tuning of potassium homeostasis. Water flowing into and out of the brain or spinal cord is assisted by AQP4. Here, AQP4 channels respond passively to osmotic gradients. In addition, they play a role in brain water transport, cell migration, brain edema, metabolism and cell homeostasis.

Other systems are also regulated by AQP4. Within the inner ear, the main role is to provide osmotic balance in supporting epithelium cells within the organ of Corti by recycling K⁺. Another specific role AQP4 plays is to help odorant molecules bind to target receptors and binding proteins within olfactory epithelium. Within the retina, the role of AQP-4 is to maintain homeostasis. Aquaporin-4 is essential in the formation of memory as well as synaptic plasticity.Other performances that aquaporin-4 is involved in are synaptic plasticity, astrocyte migration, regulation of extracellular space volume, and the homeostasis of potassium

Stucture

The structure of AQP4 consists of six-transmembrane domains and five connecting loops to form the channel. Through x-ray crystallography, it was found that “each AQP4 monomer consists of six helical, membrane-spanning domains and two short helical segments surrounding a narrow aqueous pore.” Similar to other aquaporin channels, the monomers of AQP4 assemble into tetramers. In addition, AQP4 has two distinct structural isoforms located in the CNS: M1 and M23. Both form homo- and hetero-tetramers that are permeable to water. M23 isoforms are larger square arrays in the endfoot membranes of astrocytes compared to M1 isoforms, which are smaller and more unstable. The aquaporin-4 tetramers accumulate to transform into orthogonal arrays of particle (OAPs) in the cell plasma membrane