Seroatlas · Human Serome Atlas

FBL

rRNA 2'-O-methyltransferase fibrillarin

Also known as: FBRL_HUMAN, FIB, FLRN, Nop1, RNU3IP1

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

Protein identityUniProt · HPA

UniProt accession
P22087
Gene
FBL
Ensembl
ENSG00000105202
Chromosome
19
Canonical length
321 aa
Protein class
Plasma proteins, Predicted intracellular proteins
Subcellular location
Nucleoplasm,Nucleoli fibrillar center

OverviewNCBI Gene

This gene product is a component of a nucleolar small nuclear ribonucleoprotein (snRNP) particle thought to participate in the first step in processing preribosomal RNA. It is associated with the U3, U8, and U13 small nuclear RNAs and is located in the dense fibrillar component (DFC) of the nucleolus. The encoded protein contains an N-terminal repetitive domain that is rich in glycine and arginine residues, like fibrillarins in other species. Its central region resembles an RNA-binding domain and contains an RNP consensus sequence. Antisera from approximately 8% of humans with the autoimmune disease scleroderma recognize fibrillarin. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

321 residues, UniProt reviewed canonical sequence.

>P22087|FBL
     1  MKPGFSPRGG GFGGRGGFGD RGGRGGRGGF GGGRGRGGGF RGRGRGGGGG GGGGGGGGRG
    61  GGGFHSGGNR GRGRGGKRGN QSGKNVMVEP HRHEGVFICR GKEDALVTKN LVPGESVYGE
   121  KRVSISEGDD KIEYRAWNPF RSKLAAAILG GVDQIHIKPG AKVLYLGAAS GTTVSHVSDI
   181  VGPDGLVYAV EFSHRSGRDL INLAKKRTNI IPVIEDARHP HKYRMLIAMV DVIFADVAQP
   241  DQTRIVALNA HTFLRNGGHF VISIKANCID STASAEAVFA SEVKKMQQEN MKPQEQLTLE
   301  PYERDHAVVV GVYRPPPKVK N

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against FBL 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)
0.39
Highest tissue expression
247 nTPM

Expression across tissuesHPA

Tissue

  • ovary: 247 nTPM
  • skin: 214 nTPM
  • esophagus: 186 nTPM
  • cervix: 165 nTPM
  • vagina: 154 nTPM
  • pancreas: 150 nTPM

Single-cell type

  • late spermatids: 855 nCPM
  • early spermatids: 402 nCPM
  • esophageal basal cells: 377 nCPM
  • extravillous trophoblasts: 281 nCPM
  • enteric stem cells: 272 nCPM
  • basal keratinocytes: 261 nCPM

Immune cell

  • MAIT T-cell: 102 nTPM
  • naive CD4 T-cell: 101 nTPM
  • naive CD8 T-cell: 98 nTPM
  • NK-cell: 93 nTPM
  • naive B-cell: 85 nTPM
  • memory B-cell: 84 nTPM

Brain region

  • thalamus: 23 nTPM
  • white matter: 23 nTPM
  • basal ganglia: 22 nTPM
  • medulla oblongata: 22 nTPM
  • spinal cord: 21 nTPM
  • amygdala: 20 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about FBL.

Disease | ImmuneIEDB

Conditions an epitope on FBL was assayed in.

Disease | AutoantibodyPubMed

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

ReferencesPubMed · IEDB

Publications for FBL 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.

Reference: AutoantibodyPubMed

68 publications

Show 20 more of 68 total

Reference: B cellIEDB

1 publication

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. IEDB — curated epitope assays from the Immune Epitope Database (Vita et al., Nucleic Acids Research 2019). 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)
0.25
gnomAD pLI
0.99
gnomAD missense Z
1.2
DepMap mean gene effect
-1.13
DepMap dependency class
common

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 8% 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

InteractionsUniProt · HPA

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

Antibody and autoantibody relevanceSeroatlas analysis

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

FBL 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.

Source-annotated serology context

The source annotations explicitly mention antibody, autoantibody, autoantigen, or autoimmune context. This is biological context, not study-specific reactivity.

  • Antisera from approximately 8% of humans with the autoimmune disease scleroderma recognize fibrillarin.

Canonical record: https://seroatlas.com/gene/FBL. Study-independent annotations aggregated from UniProt, Human Protein Atlas, PubMed, IEDB, Pfam, InterPro, Gene Ontology, AlphaFold, gnomAD, DepMap, ClinVar, TCGA. Catalog release seroatlas-reviewed-human-uniprot-20260313.

Seroatlas is the reference for exploring autoantibody and antibody serology at the human-protein level: the autoreactome and human serome, multiplex serology (HuProt, HuScan, VirScan, PhIP-Seq).

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