Seroatlas · Human Serome Atlas

PI16

Peptidase inhibitor 16

Also known as: CD364, dJ90K10.5, MGC45378, MSMBBP, PI16_HUMAN

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

Protein identityUniProt · HPA

UniProt accession: Q6UXB8
Gene: PI16
Ensembl: ENSG00000164530
Chromosome: 6
Canonical length: 463 aa
Protein class: CD markers, Plasma proteins, Predicted membrane proteins, Predicted secreted proteins
Secretome location: Secreted to blood

OverviewNCBI Gene

Predicted to enable peptidase inhibitor activity. Predicted to act upstream of or within negative regulation of cell growth involved in cardiac muscle cell development. Predicted to be located in extracellular region. Predicted to be active in extracellular space. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

463 residues, UniProt reviewed canonical sequence.

>Q6UXB8|PI16
     1  MHGSCSFLML LLPLLLLLVA TTGPVGALTD EEKRLMVELH NLYRAQVSPT ASDMLHMRWD
    61  EELAAFAKAY ARQCVWGHNK ERGRRGENLF AITDEGMDVP LAMEEWHHER EHYNLSAATC
   121  SPGQMCGHYT QVVWAKTERI GCGSHFCEKL QGVEETNIEL LVCNYEPPGN VKGKRPYQEG
   181  TPCSQCPSGY HCKNSLCEPI GSPEDAQDLP YLVTEAPSFR ATEASDSRKM GTPSSLATGI
   241  PAFLVTEVSG SLATKALPAV ETQAPTSLAT KDPPSMATEA PPCVTTEVPS ILAAHSLPSL
   301  DEEPVTFPKS THVPIPKSAD KVTDKTKVPS RSPENSLDPK MSLTGARELL PHAQEEAEAE
   361  AELPPSSEVL ASVFPAQDKP GELQATLDHT GHTSSKSLPN FPNTSATANA TGGRALALQS
   421  SLPGAEGPDK PSVVSGLNSG PGHVWGPLLG LLLLPPLVLA GIF

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against PI16 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): 0.53
Highest tissue expression: 143 nTPM

Expression across tissuesHPA

Tissue

vagina: 143 nTPM
heart muscle: 141 nTPM
cervix: 132 nTPM
urinary bladder: 108 nTPM
breast: 62 nTPM
skin: 56 nTPM

Single-cell type

leydig cells: 336 nCPM
fibroblasts: 226 nCPM
peritubular myoid cells: 199 nCPM
hepatic stellate cells: 161 nCPM
fibro-adipogenic progenitors: 130 nCPM
oligodendrocytes: 52 nCPM

Immune cell

T-reg: 66 nTPM
memory CD4 T-cell: 20 nTPM
NK-cell: 14 nTPM
naive CD4 T-cell: 6.5 nTPM
memory CD8 T-cell: 5.7 nTPM
total PBMC: 3.3 nTPM

Brain region

white matter: 27 nTPM
basal ganglia: 23 nTPM
thalamus: 21 nTPM
hypothalamus: 21 nTPM
medulla oblongata: 20 nTPM
pons: 17 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): 1.31
gnomAD pLI: 0
gnomAD missense Z: 1.05
DepMap mean gene effect: -0.13
DepMap dependency class: selective

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

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of PI16 in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

MSMB

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads PI16 as an antibody target. Whether an autoantibody or antibody against PI16 could matter depends on whether native PI16 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

PI16 is annotated as secreted, so native PI16 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 PI16 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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