FCN2

Protein identityUniProt · HPA

UniProt accession

Q15485

Gene

FCN2

Ensembl

ENSG00000160339

Chromosome

9

Canonical length

313 aa

Protein class

Plasma proteins, Predicted secreted proteins

Secretome location

Secreted to blood

Quaternary structure

Homotrimer

OverviewNCBI Gene

The product of this gene belongs to the ficolin family of proteins. This family is characterized by the presence of a leader peptide, a short N-terminal segment, followed by a collagen-like region, and a C-terminal fibrinogen-like domain. This gene is predominantly expressed in the liver, and has been shown to have carbohydrate binding and opsonic activities. Alternatively spliced transcript variants encoding different isoforms have been identified. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

313 residues, UniProt reviewed canonical sequence.

>Q15485|FCN2
     1  MELDRAVGVL GAATLLLSFL GMAWALQAAD TCPEVKMVGL EGSDKLTILR GCPGLPGAPG
    61  PKGEAGTNGK RGERGPPGPP GKAGPPGPNG APGEPQPCLT GPRTCKDLLD RGHFLSGWHT
   121  IYLPDCRPLT VLCDMDTDGG GWTVFQRRVD GSVDFYRDWA TYKQGFGSRL GEFWLGNDNI
   181  HALTAQGTSE LRVDLVDFED NYQFAKYRSF KVADEAEKYN LVLGAFVEGS AGDSLTFHNN
   241  QSFSTKDQDN DLNTGNCAVM FQGAWWYKNC HVSNLNGRYL RGTHGSFANG INWKSGKGYN
   301  YSYKVSEMKV RPA

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against FCN2 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

Cell surface

Secreted

No

Transmembrane segments

0

Mean surface accessibility (rSASA)

0.39

Highest tissue expression

93 nTPM

Expression across tissuesHPA

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about FCN2.

Disease | GeneticClinVar

1 pathogenic / likely-pathogenic of 63 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

• Susceptibility to severe COVID-19

Disease | AutoantibodyPubMed

Conditions in which antibodies against FCN2 are reported. Each links to that disease's full target list.

• Lupus Erythematosus, Systemic 3

ReferencesPubMed · IEDB

Publications for FCN2 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)

1.53

gnomAD pLI

0

gnomAD missense Z

-0.36

DepMap mean gene effect

0.01

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

• cell surface pattern recognition receptor signaling pathway
• complement activation, lectin pathway
• defense response to Gram-negative bacterium
• defense response to Gram-positive bacterium
• opsonization
• positive regulation of opsonization
• proteolysis
• recognition of apoptotic cell

Molecular functions

• antigen binding
• calcium-dependent protein binding
• carbohydrate derivative binding
• lipoteichoic acid immune receptor activity
• mannan binding
• metal ion binding
• pattern recognition receptor activity
• proteoglycan binding
• signaling receptor binding

Cellular components

• blood microparticle
• collagen trimer
• external side of plasma membrane
• extracellular exosome
• extracellular region
• extracellular space
• serine-type endopeptidase complex
• symbiont cell surface

Protein domainsUniProt · Pfam · InterPro

• Fibrinogen, alpha/beta/gamma chain, C-terminal globular domain
• Collagen triple helix repeat
• Fibrinogen, alpha/beta/gamma chain, C-terminal globular, subdomain 1
• Fibrinogen, conserved site
• Fibrinogen-like, C-terminal
• Fibrinogen C-terminal domain-containing protein
• Fibrinogen beta and gamma chains, C-terminal globular domain
• Collagen triple helix repeat (20 copies)

KeywordsUniProt

• Calcium
• Collagen
• Complement activation lectin pathway
• Disulfide bond
• Glycoprotein
• Hydroxylation
• Immunity
• Innate immunity
• Lectin
• Metal-binding
• Repeat
• Secreted
• Signal

InteractionsUniProt · HPA

Protein binding partners of FCN2 in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

• CR1
• MASP1
• MASP2