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Protein / target

Mucin-4

Encoded byMUC4Q99102Homo sapiensSwiss-Prot
Antibody-tractable
Druggability
UniProt loc high conf
1
Research papers

Protein at a glance

Biological role

Extracellular matrix constituent, lubricant

Strongest disease association

Ovarian dysfunction

Via encoding gene MUC4 · Genetic evidence · score 0.48

Research activity

Emerging research

1 papers · latest 2020

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

Membrane-bound mucin, a family of highly glycosylated proteins that constitute the major component of the mucus, the slimy and viscous secretion covering epithelial surfaces.

View complete UniProt function annotation

Membrane-bound mucin, a family of highly glycosylated proteins that constitute the major component of the mucus, the slimy and viscous secretion covering epithelial surfaces (PubMed:10880978). These glycoproteins play important roles in the protection of the epithelium and are implicated in epithelial renewal and differentiation (PubMed:10880978). Regulates cellular behavior through both anti-adhesive effects on cell-cell and cell-extracellular matrix interactions and its ability to act as an intramembrane ligand for ERBB2. Plays an important role in proliferation and differentiation of epithelial cells by inducing specific phosphorylation of ERBB2. In polarized epithelial cells, segregates ERBB2 and other ERBB receptors and prevents ERBB2 from acting as a coreceptor. The interaction with ERBB2 leads to enhanced expression of CDKN1B. The formation of a MUC4-ERBB2-ERBB3-NRG1 complex leads to down-regulation of CDKN1B, resulting in repression of apoptosis and stimulation of proliferation. Its ability to promote tumor growth may be mainly due to repression of apoptosis as opposed to proliferation

Subcellular location

Cell membraneSecreted
Domains and Gene Ontology detail (16)

Domains & features

NIDOAMOPVWFDEGF-like 1EGF-like 2

Gene Ontology

  • Cextracellular exosome
  • Cextracellular matrix
  • Cextracellular space
  • CGolgi lumen
  • Cmembrane
  • Cplasma membrane
  • Cvesicle
  • FErbB-2 class receptor binding
  • Fextracellular matrix constituent, lubricant activity
  • Pcell-matrix adhesion
  • Pmaintenance of gastrointestinal epithelium

5412 aa · 542 kDa · 14 isoforms

Biological roles

What this protein does, drawn together from its UniProt function, Gene Ontology terms and Reactome pathways.

Receptor tyrosine kinase signallingUniProt · GOCell adhesionUniProt · GO
View supporting evidence

Receptor tyrosine kinase signalling

  • ·Membrane-bound mucin, a family of highly glycosylated proteins that constitute the major…
  • ·ErbB-2 class receptor binding

Cell adhesion

  • ·Membrane-bound mucin, a family of highly glycosylated proteins that constitute the major…
  • ·extracellular matrix
  • ·extracellular matrix constituent, lubricant activity

Concepts derived from UniProt GO Reactome — each badge above shows which sources supported that role.

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 MUC4

Gene-level evidence surfaced through the gene MUC4that 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.

COVID-19
0.51Moderately supported

Genetic evidence dominant · Open Targets 0.30

Ovarian dysfunction
0.48Limited support

Genetic evidence dominant · Open Targets 0.29

Aortic valve calcification
0.47Limited support

Genetic evidence dominant · Open Targets 0.29

Aortic Valve Stenosis
0.47Limited support

Genetic evidence dominant · Open Targets 0.29

Joint Diseases
0.43Limited support

Genetic evidence dominant · Open Targets 0.26

View evidence synthesis (5)
COVID-19Moderately supported
0.51
agreement 0.370.64
Genetic90%Literature10%

Open Targets aggregate 0.30 · 2 independent evidence families

Ovarian dysfunctionLimited support
0.48
agreement 0.360.60
Genetic100%

Open Targets aggregate 0.29 · 1 independent evidence family

Aortic valve calcificationLimited support
0.47
agreement 0.350.59
Genetic100%

Open Targets aggregate 0.29 · 1 independent evidence family

Aortic Valve StenosisLimited support
0.47
agreement 0.350.59
Genetic100%

Open Targets aggregate 0.29 · 1 independent evidence family

Joint DiseasesLimited support
0.43
agreement 0.310.55
Genetic100%

Open Targets aggregate 0.26 · 1 independent evidence family

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
Neurodegenerative Diseases0.42
COVID-190.30
Ovarian dysfunction0.29
Aortic valve calcification0.29
Aortic Valve Stenosis0.29
Joint Diseases0.26
Pancreatic Neoplasms0.21
Breast Neoplasms0.20

Tractability

AntibodiesEmerging

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

View underlying tractability evidence (4)
AB · UniProt loc high confAB · GO CC high confAB · UniProt loc med confAB · UniProt SigP or TMHMM

Raw Open Targets tractability assessment buckets, by modality.

Research activity

1 papers · to 2020

Papers linked directly to this protein. This is the protein's own literature — descriptor-derived papers are kept separate below.

Most cited

Recent

Europe PMC papers linked directly to this protein.

Related family literature

7

Papers about “Mucins” — a broader family this protein belongs to. Shown as context; not counted as papers specifically about this protein.

Mucus Structure, Viscoelastic Properties, and Composition in Chronic Respiratory Diseases.

Abrami M · International journal of molecular sciences · 2024

via Mucins

MUC1 and MUC16: critical for immune modulation in cancer therapeutics.

Chen X · Frontiers in immunology · 2024

via Mucins

Mucins and the Microbiome.

Hansson GC · Annual review of biochemistry · 2020

via Mucins

Intestinal goblet cells and mucins in health and disease: recent insights and progress.

Kim YS · Current gastroenterology reports · 2010

via Mucins

Europe PMC literature, reached through curated HGNC family membership. Membership is a taxonomic relationship — it does not imply this protein participates in every mechanism these papers discuss.