Aquaporin 4

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Aquaporin 4
PDB 2d57 EBI.png
Double layered 2D crystal structure of aquaporin-4 (AQP4M23) at 3.2 a resolution by electron crystallography.
Available structures
PDB Ortholog search: PDBe, RCSB
Symbols AQP4 ; HMIWC2; MIWC
External IDs OMIM600308 MGI107387 HomoloGene37507 IUPHAR: 691 ChEMBL: 5964 GeneCards: AQP4 Gene
Species Human Mouse
Entrez 361 11829
Ensembl ENSG00000171885 ENSMUSG00000024411
UniProt P55087 P55088
RefSeq (mRNA) NM_001650 NM_001308641
RefSeq (protein) NP_001641 NP_001295570
Location (UCSC) Chr 18:
26.85 – 26.87 Mb
Chr 18:
15.39 – 15.4 Mb
PubMed search [1] [2]

Aquaporin 4 also known as AQP4 is a protein which in humans is encoded by the AQP4 gene.[1] AQP4 belongs to the aquaporin family of integral membrane proteins that conduct water through the cell membrane.


AQP4 is constitutively expressed in the basolateral cell membrane of principal collecting duct cells in the kidney and provide a pathway for water to exit these cells.[2]

AQP4 is also expressed in astrocytes and is upregulated by direct insult to the central nervous system.[3]


Aquaporin-4 is the primary autoimmune target in neuromyelitis optica,[4][5] in which AQP4-specific IgG antibodies target astrocytic AQP4, resulting in complement activation and inflammation.[6]

See also[edit]


  1. ^ Jung JS, Bhat RV, Preston GM, Guggino WB, Baraban JM, Agre P (December 1994). "Molecular characterization of an aquaporin cDNA from brain: candidate osmoreceptor and regulator of water balance". Proceedings of the National Academy of Sciences of the United States of America 91 (26): 13052–6. doi:10.1073/pnas.91.26.13052. PMC 45579. PMID 7528931. 
  2. ^ Agre P, Nielsen S (1996). "The aquaporin family of water channels in kidney". Nephrologie 17 (7): 409–15. PMID 8987045. 
  3. ^ Nagelhus EA, Mathiisen TM, Ottersen OP (2004). "Aquaporin-4 in the central nervous system: cellular and subcellular distribution and coexpression with KIR4.1". Neuroscience 129 (4): 905–13. doi:10.1016/j.neuroscience.2004.08.053. PMID 15561407. 
  4. ^ Lennon VA, Kryzer TJ, Pittock SJ, Verkman AS, Hinson SR (August 2005). "IgG marker of optic-spinal multiple sclerosis binds to the aquaporin-4 water channel". J. Exp. Med. 202 (4): 473–7. doi:10.1084/jem.20050304. PMC 2212860. PMID 16087714. 
  5. ^ Bradl M, Lassmann DH (September 2008). "Anti-aquaporin-4 antibodies in neuromyelitis optica: how to prove their pathogenetic relevance?" (PDF). International MS Journal / MS Forum 15 (3): 75–8. PMID 18812056. 
  6. ^ Papadopoulos MC, Bennett JL, Verkman AS (Aug 12, 2014). "Treatment of neuromyelitis optica: state-of-the-art and emerging therapies.". Nature reviews. Neurology 10: 493–506. doi:10.1038/nrneurol.2014.141. PMID 25112508. 

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