Seroatlas · Human Serome Atlas

SAR1A

Small COPII coat GTPase SAR1A

Also known as: SAR1, SAR1A_HUMAN, Sara, SARA1

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

Protein identityUniProt · HPA

UniProt accession: Q9NR31
Gene: SAR1A
Ensembl: ENSG00000079332
Chromosome: 10
Canonical length: 198 aa
Protein class: Plasma proteins, Predicted intracellular proteins
Subcellular location: Endoplasmic reticulum
Quaternary structure: Homodimer

OverviewNCBI Gene

Enables G protein activity and amino acid sensor activity. Involved in COPII-coated vesicle budding; cellular response to leucine starvation; and negative regulation of TORC1 signaling. Is active in COPII vesicle coat; endoplasmic reticulum exit site; and lysosomal membrane. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

198 residues, UniProt reviewed canonical sequence.

>Q9NR31|SAR1A
     1  MSFIFEWIYN GFSSVLQFLG LYKKSGKLVF LGLDNAGKTT LLHMLKDDRL GQHVPTLHPT
    61  SEELTIAGMT FTTFDLGGHE QARRVWKNYL PAINGIVFLV DCADHSRLVE SKVELNALMT
   121  DETISNVPIL ILGNKIDRTD AISEEKLREI FGLYGQTTGK GNVTLKELNA RPMEVFMCSV
   181  LKRQGYGEGF RWLSQYID

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SAR1A 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: 154 nTPM

Expression across tissuesHPA

Tissue

bone marrow: 154 nTPM
adipose tissue: 72 nTPM
placenta: 71 nTPM
liver: 66 nTPM
tongue: 53 nTPM
choroid plexus: 52 nTPM

Single-cell type

esophageal apical cells: 356 nCPM
syncytiotrophoblasts: 309 nCPM
extravillous trophoblasts: 261 nCPM
breast lactating cells: 213 nCPM
suprabasal keratinocytes: 212 nCPM
gastric progenitor cells: 208 nCPM

Immune cell

NK-cell: 104 nTPM
total PBMC: 96 nTPM
MAIT T-cell: 95 nTPM
naive CD8 T-cell: 89 nTPM
gdT-cell: 88 nTPM
memory CD8 T-cell: 86 nTPM

Brain region

choroid plexus: 86 nTPM
white matter: 81 nTPM
thalamus: 78 nTPM
hypothalamus: 77 nTPM
spinal cord: 75 nTPM
midbrain: 70 nTPM

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): 0.7
gnomAD pLI: 0.37
gnomAD missense Z: 2.09
DepMap mean gene effect: -0.16
DepMap dependency class: selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 5% 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 SAR1A 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 SAR1A as an antibody target. Whether an autoantibody or antibody against SAR1A could matter depends on whether native SAR1A is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

SAR1A 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 SAR1A as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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