Protein / target

Aquaporin-4

Encoded byAQP4P55087Homo sapiensSwiss-Prot

UniProt: P55087 Ensembl: ENSG00000171885 HGNC: HGNC:637 NCBI Gene: 361

Antibody-tractable

Druggability

UniProt loc high conf

Research papers

Protein at a glance

Biological role

Identical protein binding

Strongest disease association

Cardiomyopathy, Hypertrophic

Via encoding gene AQP4 · Genetic evidence · score 0.52

Research activity

Emerging research

9 papers · latest 2025

Derived from structured UniProt, Open Targets and literature data on this page.

Protein profile

UniProt 2026_02

Canonical identity and biological annotation from UniProt.

Function overview

Forms a water-specific channel.

View complete UniProt function annotation

Forms a water-specific channel (PubMed:19383790, PubMed:7559426, PubMed:8601457). Plays an important role in brain water homeostasis (PubMed:37143309). It is involved in glymphatic solute transport and is required for a normal rate of water exchange across the blood brain interface. Required for normal levels of cerebrospinal fluid influx into the brain cortex and parenchyma along paravascular spaces that surround penetrating arteries, and for normal drainage of interstitial fluid along paravenous drainage pathways. Thereby, it is required for normal clearance of solutes from the brain interstitial fluid, including soluble beta-amyloid peptides derived from APP. Plays a redundant role in urinary water homeostasis and urinary concentrating ability (By similarity)

Subcellular location

Cell membraneBasolateral cell membraneEndosome membraneCell membrane, sarcolemmaCell projection

Domains and Gene Ontology detail (18)

Gene Ontology

Castrocyte end-foot
Cbasolateral plasma membrane
Ccell junction
Ccytoplasm
Cendosome membrane
Cexternal side of plasma membrane
Cextracellular region
Cplasma membrane
Csarcolemma
Fidentical protein binding
Fwater channel activity
Pcellular response to type II interferon

323 aa · 35 kDa · 2 isoforms

Translational evidence

Open Targets 26

Why this target matters therapeutically, strongest evidence first. Disease associations are gene-level (via the gene that encodes this protein) and open into the full confidence synthesis; the development universe, tractability and safety annotations are target-level, from Open Targets.

Strongest disease associations · via encoding gene AQP4

Gene-level evidence surfaced through the gene AQP4that encodes this protein — not a direct protein–disease relationship. Ranked by Forefront's causal-directness weighting, so genetically- and clinically-evidenced diseases lead over ones that merely share the literature.

Cardiomyopathy, Hypertrophic

0.52Moderately supported

Genetic evidence dominant · Open Targets 0.32

Poisoning

0.43Limited support

Genetic evidence dominant · Open Targets 0.26

Kidney Failure, Chronic

0.37Limited support

Genetic evidence dominant · Open Targets 0.22

Pre-Eclampsia

0.36Limited support

Genetic evidence dominant · Open Targets 0.22

Breast Neoplasms

0.29Limited support

Genetic evidence dominant · Open Targets 0.16

View evidence synthesis (5)

Cardiomyopathy, HypertrophicModerately supported

0.52

agreement 0.39–0.66

Genetic100%Literature0%

Open Targets aggregate 0.32 · 2 independent evidence families

PoisoningLimited support

0.43

agreement 0.31–0.55

Genetic100%

Open Targets aggregate 0.26 · 1 independent evidence family

Kidney Failure, ChronicLimited support

0.37

agreement 0.23–0.51

Genetic94%Literature6%

Open Targets aggregate 0.22 · 2 independent evidence families

Pre-EclampsiaLimited support

0.36

agreement 0.22–0.50

Genetic96%Literature5%

Open Targets aggregate 0.22 · 2 independent evidence families

Breast NeoplasmsLimited support

0.29

agreement 0.15–0.43

Genetic83%Literature17%

Open Targets aggregate 0.16 · 2 independent evidence families

The evidence agreement range shows how closely the independent evidence families agree — it is not a statistical confidence interval, and nothing here is fitted to outcome data. Derived from Open Targets evidence types under Forefront weighting; the per-type scores above show the calculation.

Show all associations

Cardiomyopathy, Hypertrophic0.32

Poisoning0.26

Kidney Failure, Chronic0.22

Pre-Eclampsia0.22

Breast Neoplasms0.16

Tractability

Antibodies — Emerging

Feasibility evidence (uniprot loc high conf and go cc high conf) — no clinical-stage drug of this modality recorded.

Protein degraders — Emerging

Feasibility evidence (half-life data) — no clinical-stage drug of this modality recorded.

View underlying tractability evidence (6)