Seroatlas · Human Serome Atlas

SAR1B

Small COPII coat GTPase SAR1B

Also known as: SAR1B_HUMAN, SARA2

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

Protein identityUniProt · HPA

UniProt accession
Q9Y6B6
Gene
SAR1B
Ensembl
ENSG00000152700
Chromosome
5
Canonical length
198 aa
Protein class
Disease related genes, Human disease related genes, Plasma proteins, Predicted intracellular proteins
Subcellular location
Endoplasmic reticulum
Quaternary structure
Homodimer

OverviewNCBI Gene

The protein encoded by this gene is a small GTPase that acts as a homodimer. The encoded protein is activated by the guanine nucleotide exchange factor PREB and is involved in protein transport from the endoplasmic reticulum to the Golgi. This protein is part of the COPII coat complex. Defects in this gene are a cause of chylomicron retention disease (CMRD), also known as Anderson disease (ANDD). Two transcript variants encoding the same protein have been found for this gene. [provided by RefSeq, Mar 2010]

Canonical amino-acid sequenceUniProt

198 residues, UniProt reviewed canonical sequence.

>Q9Y6B6|SAR1B
     1  MSFIFDWIYS GFSSVLQFLG LYKKTGKLVF LGLDNAGKTT LLHMLKDDRL GQHVPTLHPT
    61  SEELTIAGMT FTTFDLGGHV QARRVWKNYL PAINGIVFLV DCADHERLLE SKEELDSLMT
   121  DETIANVPIL ILGNKIDRPE AISEERLREM FGLYGQTTGK GSISLKELNA RPLEVFMCSV
   181  LKRQGYGEGF RWMAQYID

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SAR1B 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
Other membrane
Secreted
No
Transmembrane segments
0
Mean surface accessibility (rSASA)
0.27
Highest tissue expression
153 nTPM

Expression across tissuesHPA

Tissue

  • liver: 153 nTPM
  • skeletal muscle: 137 nTPM
  • tongue: 131 nTPM
  • small intestine: 65 nTPM
  • duodenum: 64 nTPM
  • testis: 61 nTPM

Single-cell type

  • early spermatids: 438 nCPM
  • late primary spermatocytes: 397 nCPM
  • esophageal apical cells: 337 nCPM
  • hepatocytes: 334 nCPM
  • breast lactating cells: 269 nCPM
  • enterocytes: 257 nCPM

Immune cell

  • non-classical monocyte: 81 nTPM
  • T-reg: 77 nTPM
  • total PBMC: 72 nTPM
  • intermediate monocyte: 71 nTPM
  • classical monocyte: 71 nTPM
  • myeloid DC: 64 nTPM

Brain region

  • white matter: 109 nTPM
  • medulla oblongata: 93 nTPM
  • cerebellum: 85 nTPM
  • choroid plexus: 85 nTPM
  • spinal cord: 85 nTPM
  • midbrain: 84 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about SAR1B.

Disease | AllUniProt

Conditions SAR1B is implicated in, by any mechanism.

Disease | GeneticClinVar

24 pathogenic / likely-pathogenic of 197 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

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)
0.99
gnomAD pLI
0
gnomAD missense Z
0.81
DepMap mean gene effect
-0.04
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 4% 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 SAR1B 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 SAR1B as an antibody target. Whether an autoantibody or antibody against SAR1B could matter depends on whether native SAR1B is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

SAR1B 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.

Annotation status

The present source text does not explicitly label SAR1B as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/SAR1B. 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...