Seroatlas · Human Serome Atlas

PRG3

Proteoglycan 3

Also known as: MBP2, MBPH, PRG3_HUMAN

Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene

Protein identityUniProt · HPA

UniProt accession: Q9Y2Y8
Gene: PRG3
Ensembl: ENSG00000156575
Chromosome: 11
Canonical length: 225 aa
Protein class: Predicted secreted proteins
Secretome location: Secreted in other tissues

OverviewNCBI Gene

An extracellular matrix structural constituent conferring compression resistance. Involved in several processes, including granulocyte activation; histamine biosynthetic process; and regulation of gene expression. Located in collagen-containing extracellular matrix. [provided by Alliance of Genome Resources, Apr 2025]

Canonical amino-acid sequenceUniProt

225 residues, UniProt reviewed canonical sequence.

>Q9Y2Y8|PRG3
     1  MQCLLLLPFL LLGTVSALHL ENDAPHLESL ETQADLGQDL DSSKEQERDL ALTEEVIQAE
    61  GEEVKASACQ DNFEDEEAME SDPAALDKDF QCPREEDIVE VQGSPRCKIC RYLLVRTPKT
   121  FAEAQNVCSR CYGGNLVSIH DFNFNYRIQC CTSTVNQAQV WIGGNLRGWF LWKRFCWTDG
   181  SHWNFAYWSP GQPGNGQGSC VALCTKGGYW RRAQCDKQLP FVCSF

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against PRG3 can act on the native protein depends on physical access: surface and secreted proteins are reachable by circulating antibodies, intracellular proteins usually are not.

Antibody reachability: Intracellular
Secreted: No
Transmembrane segments: 0
Mean surface accessibility (rSASA): 0.45
Highest tissue expression: 46 nTPM

Expression across tissuesHPA

Tissue

bone marrow: 46 nTPM
thymus: 3.8 nTPM
spleen: 1.5 nTPM
liver: 1 nTPM
lung: 0.4 nTPM
lymph node: 0.2 nTPM

Single-cell type

monocyte progenitors: 13 nCPM
retinal amacrine cells: 0.7 nCPM
retinal bipolar cells: 0.5 nCPM
erythrocyte progenitors: 0.2 nCPM
cdc: 0.1 nCPM
hofbauer cells: 0.1 nCPM

Immune cell

basophil: 0 nTPM
classical monocyte: 0 nTPM
eosinophil: 0 nTPM
gdT-cell: 0 nTPM
intermediate monocyte: 0 nTPM
MAIT T-cell: 0 nTPM

Brain region

cerebral cortex: 0.5 nTPM
pons: 0.1 nTPM
amygdala: 0 nTPM
basal ganglia: 0 nTPM
cerebellum: 0 nTPM
choroid plexus: 0 nTPM

Genetic constraint and essentialitygnomAD · DepMap

Does the body need this protein intact? Low LOEUF or a strong DepMap dependency means loss or blockade of the protein is likely to be felt.

gnomAD LOEUF (loss-of-function intolerance): 1.14
gnomAD pLI: 0
gnomAD missense Z: -0.45
DepMap mean gene effect: 0.03
DepMap dependency class: none

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 3% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads PRG3 as an antibody target. Whether an autoantibody or antibody against PRG3 could matter depends on whether native PRG3 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

PRG3 is annotated as predominantly intracellular. Intracellular proteins are common autoantibody markers, becoming visible to the immune system after cell injury or altered processing, but are usually markers of disease rather than direct drivers.

Annotation status

The present source text does not explicitly label PRG3 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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