Seroatlas · Human Serome Atlas

SSB

Lupus La protein

Also known as: La, LA_HUMAN, La/SSB, LARP3

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

Protein identityUniProt · HPA

UniProt accession
P05455
Gene
SSB
Ensembl
ENSG00000138385
Chromosome
2
Canonical length
408 aa
Protein class
Predicted intracellular proteins
Subcellular location
Nucleoplasm

OverviewNCBI Gene

The protein encoded by this gene is involved in diverse aspects of RNA metabolism, including binding and protecting poly(U) termini of nascent RNA polymerase III transcripts from exonuclease digestion, processing 5' and 3' ends of pre-tRNA precursors, acting as an RNA chaperone, and binding viral RNAs associated with hepatitis C virus. Autoantibodies reacting with this protein are found in the sera of patients with Sjogren syndrome and systemic lupus erythematosus. Alternative promoter usage results in two different transcript variants which encode the same protein. [provided by RefSeq, Jun 2014]

Canonical amino-acid sequenceUniProt

408 residues, UniProt reviewed canonical sequence.

>P05455|SSB
     1  MAENGDNEKM AALEAKICHQ IEYYFGDFNL PRDKFLKEQI KLDEGWVPLE IMIKFNRLNR
    61  LTTDFNVIVE ALSKSKAELM EISEDKTKIR RSPSKPLPEV TDEYKNDVKN RSVYIKGFPT
   121  DATLDDIKEW LEDKGQVLNI QMRRTLHKAF KGSIFVVFDS IESAKKFVET PGQKYKETDL
   181  LILFKDDYFA KKNEERKQNK VEAKLRAKQE QEAKQKLEED AEMKSLEEKI GCLLKFSGDL
   241  DDQTCREDLH ILFSNHGEIK WIDFVRGAKE GIILFKEKAK EALGKAKDAN NGNLQLRNKE
   301  VTWEVLEGEV EKEALKKIIE DQQESLNKWK SKGRRFKGKG KGNKAAQPGS GKGKVQFQGK
   361  KTKFASDDEH DEHDENGATG PVKRAREETD KEEPASKQQK TENGAGDQ

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SSB 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)
0.41
Highest tissue expression
107 nTPM

Expression across tissuesHPA

Tissue

  • adipose tissue: 107 nTPM
  • bone marrow: 99 nTPM
  • choroid plexus: 97 nTPM
  • lymph node: 87 nTPM
  • blood vessel: 85 nTPM
  • urinary bladder: 83 nTPM

Single-cell type

  • oocytes: 484 nCPM
  • fallopian tube ciliated cells: 313 nCPM
  • respiratory ciliated cells: 313 nCPM
  • migrating cytotrophoblasts: 300 nCPM
  • erythrocyte progenitors: 297 nCPM
  • esophageal basal cells: 268 nCPM

Immune cell

  • non-classical monocyte: 105 nTPM
  • MAIT T-cell: 105 nTPM
  • memory CD4 T-cell: 102 nTPM
  • T-reg: 102 nTPM
  • naive CD8 T-cell: 98 nTPM
  • NK-cell: 95 nTPM

Brain region

  • choroid plexus: 67 nTPM
  • cerebral cortex: 59 nTPM
  • midbrain: 57 nTPM
  • hypothalamus: 55 nTPM
  • pons: 51 nTPM
  • medulla oblongata: 51 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about SSB.

Disease | ImmuneIEDB

Conditions an epitope on SSB was assayed in.

Disease | AutoantibodyPubMed

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

Showing 20 of 45 — disease pages carrying at least 10 antigens.

ReferencesPubMed · IEDB

Publications for SSB 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

578 publications

Show 20 more of 578 total

Reference: B cellIEDB

14 publications

Show 9 more

Reference: T 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)
0.54
gnomAD pLI
0.09
gnomAD missense Z
1.49
DepMap mean gene effect
-0.67
DepMap dependency class
common

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 7% 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 SSB 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 SSB as an antibody target. Whether an autoantibody or antibody against SSB could matter depends on whether native SSB is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

SSB 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.

  • Autoantibodies reacting with this protein are found in the sera of patients with Sjogren syndrome and systemic lupus erythematosus.

Canonical record: https://seroatlas.com/gene/SSB. 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).

© 2026 · Seroatlas, Discover Oregon LLC · Terms of use

Loading the interactive Seroatlas protein explorer...