BPIFA1

Protein identityUniProt · HPA

UniProt accession

Q9NP55

Gene

BPIFA1

Ensembl

ENSG00000198183

Chromosome

20

Canonical length

256 aa

Protein class

Plasma proteins, Predicted secreted proteins

Secretome location

Secreted in other tissues

OverviewNCBI Gene

This gene is the human homolog of murine plunc, and like the mouse gene, is specifically expressed in the upper airways and nasopharyngeal regions. The encoded antimicrobial protein displays antibacterial activity against Gram-negative bacteria. It is thought to be involved in inflammatory responses to irritants in the upper airways and may also serve as a potential molecular marker for detection of micrometastasis in non-small-cell lung cancer. Multiple transcript variants resulting from alternative splicing in the 3' UTR have been detected, but the full-length nature of only three are known. [provided by RefSeq, Aug 2014]

Canonical amino-acid sequenceUniProt

256 residues, UniProt reviewed canonical sequence.

>Q9NP55|BPIFA1
     1  MFQTGGLIVF YGLLAQTMAQ FGGLPVPLDQ TLPLNVNPAL PLSPTGLAGS LTNALSNGLL
    61  SGGLLGILEN LPLLDILKPG GGTSGGLLGG LLGKVTSVIP GLNNIIDIKV TDPQLLELGL
   121  VQSPDGHRLY VTIPLGIKLQ VNTPLVGASL LRLAVKLDIT AEILAVRDKQ ERIHLVLGDC
   181  THSPGSLQIS LLDGLGPLPI QGLLDSLTGI LNKVLPELVQ GNVCPLVNEV LRGLDITLVH
   241  DIVNMLIHGL QFVIKV

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against BPIFA1 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)

0.38

Highest tissue expression

19 nTPM

Expression across tissuesHPA

ReferencesPubMed · IEDB

Publications for BPIFA1 from three distinct lines of evidence, kept separate because they answer different questions: whether antibodies are directed at the protein, whether a B-cell epitope has been mapped on it, and whether a T-cell epitope has. Each is labelled with its source.

Sources: PubMed — antigen-level antibody evidence from a custom retrieval. Records matching a controlled set of autoantibody terms (the MeSH descriptors Autoantibodies and Autoantigens, with title and abstract term variants) were obtained through NCBI E-utilities, and their titles and abstracts parsed for constructions that direct an antibody at a named protein rather than for co-occurrence. Captured names were resolved against UniProt nomenclature and each antigen adjudicated individually against the source text. Bibliographic records from PubMed and MeSH, U.S. National Library of Medicine; citation metrics from NIH iCite (Hutchins et al., PLoS Biology 2016). Titles link to PubMed; abstracts are not reproduced here. The NLM does not endorse this analysis.

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)

1.64

gnomAD pLI

0

gnomAD missense Z

-0.44

DepMap mean gene effect

0.06

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

• antibacterial humoral response
• antimicrobial humoral immune response mediated by antimicrobial peptide
• defense response to virus
• immune response in nasopharyngeal-associated lymphoid tissue
• innate immune response
• multicellular organismal-level water homeostasis
• negative regulation of single-species biofilm formation in or on host organism
• regulation of sodium ion transmembrane transport
• surfactant homeostasis

Molecular functions

• lipid binding

Cellular components

• extracellular region
• extracellular space

Protein domainsUniProt · Pfam · InterPro

• Lipid-binding serum glycoprotein, N-terminal
• Bactericidal permeability-increasing protein, alpha/beta domain superfamily
• BPI fold-containing superfamily member
• LBP / BPI / CETP family, N-terminal domain

KeywordsUniProt

• Antibiotic
• Antimicrobial
• Disulfide bond
• Glycoprotein
• Immunity
• Innate immunity
• Lipid-binding
• Secreted
• Signal

InteractionsUniProt · HPA

Protein binding partners of BPIFA1 in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

• SCNN1A
• SCNN1G