Seroatlas · Human Serome Atlas

PIP

Prolactin-inducible protein

Also known as: BRST-2, GCDFP-15, GCDFP15, GPIP4, PIP_HUMAN, SABP

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

Protein identityUniProt · HPA

UniProt accession: P12273
Gene: PIP
Ensembl: ENSG00000159763
Chromosome: 7
Canonical length: 146 aa
Protein class: Plasma proteins, Predicted secreted proteins
Secretome location: Secreted in other tissues

OverviewNCBI Gene

Enables IgG binding activity; aspartic-type endopeptidase activity; and identical protein binding activity. Involved in several processes, including detection of chemical stimulus involved in sensory perception of bitter taste; negative regulation of T cell apoptotic process; and proteolysis. Located in extracellular space and nucleus. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

146 residues, UniProt reviewed canonical sequence.

>P12273|PIP
     1  MRLLQLLFRA SPATLLLVLC LQLGANKAQD NTRKIIIKNF DIPKSVRPND EVTAVLAVQT
    61  ELKECMVVKT YLISSIPLQG AFNYKYTACL CDDNPKTFYW DFYTNRTVQI AAVVDVIREL
   121  GICPDDAAVI PIKNNRFYTI EILKVE

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against PIP 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: Secreted
Secreted: Yes
Transmembrane segments: 0
Mean surface accessibility (rSASA): 0.37
Highest tissue expression: 17,175 nTPM

Expression across tissuesHPA

Tissue

salivary gland: 17,175 nTPM
breast: 3,247 nTPM
seminal vesicle: 2,949 nTPM
skin: 183 nTPM
prostate: 28 nTPM
pancreas: 20 nTPM

Single-cell type

lacrimal acinar cells: 23,034 nCPM
salivary acinar cells: 5,978 nCPM
breast hormone-responsive cells: 1,898 nCPM
salivary myoepithelial cells: 1,045 nCPM
submucosal glandular cells: 671 nCPM
salivary duct cells: 253 nCPM

Immune cell

naive B-cell: 0.5 nTPM
memory B-cell: 0.4 nTPM
basophil: 0 nTPM
classical monocyte: 0 nTPM
eosinophil: 0 nTPM
gdT-cell: 0 nTPM

Brain region

white matter: 26 nTPM
medulla oblongata: 22 nTPM
pons: 16 nTPM
basal ganglia: 13 nTPM
thalamus: 13 nTPM
hypothalamus: 13 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): 1.69
gnomAD pLI: 0
gnomAD missense Z: -0.19
DepMap mean gene effect: -0.01
DepMap dependency class: none

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 2% 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

Immunoglobulin-like fold
Immunoglobulin E-set
Prolactin-inducible protein
Seminal vesicle autoantigen (SVA)

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of PIP in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

AZGP1

Antibody and autoantibody relevanceSeroatlas analysis

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

PIP is annotated as secreted, so native PIP circulates and is directly accessible to antibodies. Secreted and cell-surface proteins are the autoantibody targets most likely to act like drugs, blocking or depleting the native protein.

Annotation status

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

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