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TSPO2

gene
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Also known as dJ34B21.2

Summary

TSPO2 (translocator protein 2, HGNC:21256) is a protein-coding gene on chromosome 6p21.1, encoding Translocator protein 2 (Q5TGU0). Cholesterol-binding protein involved in the redistribution of cholesterol from lipid droplets to the endoplasmic reticulum.

Enables 5-aminolevulinic acid transmembrane transporter activity. Involved in 5-aminolevulinic acid import across plasma membrane. Located in plasma membrane.

Source: NCBI Gene 222642 — automated summary from GO annotations (Alliance of Genome Resources).

At a glance

  • GWAS associations: 2
  • Clinical variants (ClinVar): 20 total
  • GTEx eGene: eQTL in 4 tissues, sQTL in 1 (q < 0.05)
  • Constraint (gnomAD): pLI 0.00 (LoF-tolerant), LOEUF 1.64 (unconstrained)
  • MANE Select transcript: NM_001010873

Identifiers

Gene identifiers

FieldValue
HGNC IDHGNC:21256
Approved symbolTSPO2
Nametranslocator protein 2
Location6p21.1
Locus typegene with protein product
StatusApproved
AliasesdJ34B21.2
Ensembl geneENSG00000112212
Ensembl biotypeprotein_coding
OMIM619409
Entrez222642

Gene structure

Transcript identifiers

Ensembl transcripts: 10 — 10 protein_coding

MANE Select: ENST00000373161

Transcript support level (Ensembl TSL; 1 = fully mRNA-supported): TSL 1: 3

ENST00000373161, ENST00000373158, ENST00000470917, ENST00000984170, ENST00001103123, ENST00001103124, ENST00001103125, ENST00001103126, ENST00001103127, ENST00001138256

RefSeq mRNA: 2 — MANE Select: NM_001010873 NM_001010873, NM_001159726

CCDS: CCDS34444

Canonical transcript exons

ENST00000373161 — 4 exons

ExonStartEnd
ENSE000007506574104355741043698
ENSE000014596814104296641043158
ENSE000014596824104246741042778
ENSE000018207794104394041044337

Expression profiles

Bgee: expression breadth ubiquitous, 140 present calls, max score 87.22.

FANTOM5 (CAGE): breadth tissue_specific, TPM avg 0.0525 / max 43.5445, expressed in 4 samples.

Highest expression (Bgee): trabecular bone tissue, bone marrow, bone marrow cell, blood, Brodmann (1909) area 10.

Genetic regulation across tissues (GTEx eQTL / sQTL)

TSPO2 is an eGene in GTEx v10 — its expression is genetically regulated (eQTL) in 4 tissues and its splicing (sQTL) in 1 (q < 0.05). Strongest associations first; slope = normalized effect of the lead variant’s alternative allele.

5 significant tissue × QTL associations:

TissueQTLq-valueSlopeLead variant
Testiseqtl8.4e-11-0.476:41037763:T:C
Esophagus Mucosaeqtl2.2e-02-0.716:40896019:T:C
Esophagus Gastroesophageal Junctioneqtl2.5e-02+0.536:40374375:A:G
Minor Salivary Glandeqtl3.0e-02-0.426:40370560:T:C
Whole Bloodsqtl3.3e-02-1.116:40846973:T:C

FANTOM5 promoters

2 alternative TSS:

Promoter IDTPM avgSamples expressed
677220.03254
677230.01993

Top tissues by expression

showing 100 of 280 tissues by Bgee expression score (0-100, higher = more expressed):

TissueAnatomy IDExpression scoreQuality
trabecular bone tissueUBERON:000248387.22gold quality
bone marrowUBERON:000237185.12gold quality
bone marrow cellCL:000209273.64gold quality
bloodUBERON:000017869.15gold quality
Brodmann (1909) area 10UBERON:001354168.66gold quality
mononuclear cellCL:000084265.48gold quality
monocyteCL:000057665.46gold quality
leukocyteCL:000073863.01gold quality
sural nerveUBERON:001548861.26gold quality
cerebellar vermisUBERON:000472058.83gold quality
jejunal mucosaUBERON:000039958.66silver quality
gall bladderUBERON:000211057.79gold quality
duodenumUBERON:000211457.71gold quality
endometrium epitheliumUBERON:000481157.39gold quality
islet of LangerhansUBERON:000000656.23gold quality
adult mammalian kidneyUBERON:000008255.98gold quality
right lobe of liverUBERON:000111455.66gold quality
liverUBERON:000210755.52gold quality
upper leg skinUBERON:000426255.41silver quality
body of stomachUBERON:000116155.40gold quality
small intestineUBERON:000210854.83gold quality
thymusUBERON:000237054.67silver quality
small intestine Peyer’s patchUBERON:000345454.62gold quality
stomachUBERON:000094553.63gold quality
quadriceps femorisUBERON:000137753.47gold quality
metanephrosUBERON:000008152.91gold quality
paraflocculusUBERON:000535152.73gold quality
epithelium of esophagusUBERON:000197652.66gold quality
mucosa of stomachUBERON:000119952.54gold quality
vastus lateralisUBERON:000137952.42gold quality
esophagus squamous epitheliumUBERON:000692052.30gold quality
spleenUBERON:000210652.17gold quality
metanephros cortexUBERON:001053352.17gold quality
pancreasUBERON:000126452.14gold quality
oocyteCL:000002351.87gold quality
tibiaUBERON:000097951.66gold quality
pancreatic ductal cellCL:000207951.33silver quality
kidneyUBERON:000211351.33gold quality
deltoidUBERON:000147651.04gold quality
squamous epitheliumUBERON:000691450.71gold quality
body of pancreasUBERON:000115050.51gold quality
frontal poleUBERON:000279550.41gold quality
middle frontal gyrusUBERON:000270250.30gold quality
muscle tissueUBERON:000238549.74silver quality
epithelial cell of pancreasCL:000008349.70gold quality
layer of synovial tissueUBERON:000761649.53gold quality
Brodmann (1909) area 46UBERON:000648349.49gold quality
blood vessel layerUBERON:000479749.29gold quality
dorsal motor nucleus of vagus nerveUBERON:000287049.27gold quality
cervix squamous epitheliumUBERON:000692249.20gold quality
hair follicleUBERON:000207349.18gold quality
orbitofrontal cortexUBERON:000416749.13gold quality
placentaUBERON:000198749.04gold quality
skeletal muscle tissueUBERON:000113448.94gold quality
olfactory bulbUBERON:000226448.92gold quality
choroid plexus epitheliumUBERON:000391148.89gold quality
myocardiumUBERON:000234948.87gold quality
cortex of kidneyUBERON:000122548.85gold quality
type B pancreatic cellCL:000016948.83gold quality
skin of legUBERON:000151148.83gold quality
right lungUBERON:000216748.74gold quality
nephron tubuleUBERON:000123148.62gold quality
cardiac muscle of right atriumUBERON:000337948.55gold quality
nasal cavity mucosaUBERON:000182648.51gold quality
CA1 field of hippocampusUBERON:000388148.50gold quality
oviduct epitheliumUBERON:000480448.48gold quality
left ventricle myocardiumUBERON:000656648.24gold quality
upper arm skinUBERON:000426348.06gold quality
cervix epitheliumUBERON:000480148.04gold quality
kidney epitheliumUBERON:000481947.92gold quality
tongue squamous epitheliumUBERON:000691947.92gold quality
intestineUBERON:000016047.90gold quality
transverse colonUBERON:000115747.85gold quality
mucosa of urinary bladderUBERON:000125947.80gold quality
metanephric glomerulusUBERON:000473647.74gold quality
nasal cavity epitheliumUBERON:000538447.70gold quality
renal glomerulusUBERON:000007447.60gold quality
tibial nerveUBERON:000132347.34gold quality
cranial nerve IIUBERON:000094147.28silver quality
granulocyteCL:000009447.20silver quality
zone of skinUBERON:000001447.17gold quality
periodontal ligamentUBERON:000826647.14gold quality
diaphragmUBERON:000110347.05gold quality
gluteal muscleUBERON:000200047.03gold quality
triceps brachiiUBERON:000150947.01gold quality
tibialis anteriorUBERON:000138546.82silver quality
tonsilUBERON:000237246.59silver quality
skin of abdomenUBERON:000141646.38gold quality
left adrenal gland cortexUBERON:003582545.89gold quality
large intestineUBERON:000005945.64gold quality
lateral nuclear group of thalamusUBERON:000273645.51gold quality
substantia nigra pars reticulataUBERON:000196645.50gold quality
anatomical systemUBERON:000046745.48gold quality
colonUBERON:000115545.45gold quality
material anatomical entityUBERON:000046545.42gold quality
multicellular organismUBERON:000046845.42gold quality
adrenal cortexUBERON:000123545.33gold quality
epithelium of bronchusUBERON:000203145.30gold quality
fundus of stomachUBERON:000116045.17gold quality
right adrenal gland cortexUBERON:003582745.16gold quality

Single-cell (SCXA)

Detected in 6 experiment(s), a significant marker in 3.

ExperimentMarker?Max mean expression
E-MTAB-10042yes138.78
E-HCAD-9yes6.51
E-MTAB-9067yes4.66
E-HCAD-10no1.96
E-ANND-3no1.29
E-MTAB-9467no0.62

HPA expression

RNA tissue specificity: Tissue enriched

48 HPA tissues / cells by nTPM:

Tissue / cellAxisnTPM
Bone marrowtissue47.3
Olfactory bulbtissue7.7
Cerebellumtissue6.4
Cerebral cortextissue5.4
Retrosplenial and cingulate cortextissue5.4
Retrosplenial cortextissue5.0
Temporal cortextissue5.0
Basal gangliatissue4.9
Insular cortextissue4.9
Amygdalatissue4.7
Hippocampal formationtissue4.5
Entorhinal cortextissue4.5
Occipital cortextissue4.4
Prefrontal cortextissue3.9
Ventral forebraintissue3.9
Motor cortextissue3.8
Putamentissue3.5
Corpus callosumtissue3.5
Septumtissue3.4
Somatosensory cortextissue3.4
Periaqueductal graytissue3.3
Hypothalamustissue2.8
Midbraintissue2.7
Nucleus accumbenstissue2.1
Substantia nigratissue2.1
Locus coeruleustissue2.1
Ponstissue2.0
Medulla oblongatatissue2.0
Superior colliculitissue2.0
Spinal cordtissue2.0
Choroid plexustissue1.9
Thalamustissue1.7
Hippocampustissue1.7
Postcentral gyrustissue1.4
Placentatissue1.1
Duodenumtissue1.1
Small intestinetissue0.7
Gallbladdertissue0.6
Skin 1tissue0.5
Stomach 1tissue0.5
Kidneytissue0.5
Retinatissue0.3
Testistissue0.2
Livertissue0.2
Lymph nodetissue0.1
Heart muscletissue0.1
Skeletal muscletissue0.1
Appendixtissue0.1

Brain sub-regions (HPA Brain Atlas): detected in 188; highest nTPM — Parieto-temporal junction (white matter) (5.4), Medial olivary nucleus (4.2), Temporal white matter (4.1), Corpus callosum, genu (white matter) (4.0), Nucleus raphe obscurus (4.0).

Regulation

Is transcription factor: no

Functional genomics

gnomAD constraint: pLI 2.8e-08, LOEUF 1.64, missense Z 0.111 — population loss-of-function intolerance (pLI ≥ 0.9 = LoF-intolerant; lower LOEUF = more constrained). gnomAD

Regional missense constraint (gnomAD RMC): no regional variation along ENST00000373161 — one region, missense o/e 1.02.

Literature-anchored findings (GeneRIF, showing 2)

  • identify the TSPO2 family of proteins as mediators of cholesterol redistribution-dependent erythroblast maturation during mammalian erythropoiesis (PMID:19729679)
  • TSPO ligands can induce Plasmodium falciparum death by increasing the uptake of porphyrins through a TSPO2-VDAC complex, which leads to an accumulation of reactive oxygen species. (PMID:27641616)

Cross-species orthologs

5 orthologs

OrganismSymbolGene ID
danio_reriotspoENSDARG00000026655
mus_musculusTspo2ENSMUSG00000023995
rattus_norvegicusTspo2ENSRNOG00000050521
drosophila_melanogasterTspoFBGN0031263
caenorhabditis_eleganstspo-1WBGENE00077771

Paralogs (1): TSPO (ENSG00000100300)

Mouse-model phenotypes

Observed phenotypes of the mouse ortholog (MGI:1917276) from MGI (Alliance of Genome Resources) — knockout/mutant phenotypes, ranked by annotation count. 6 distinct phenotype terms.

Mouse phenotype (MP)Records
decreased hematocrit1
reticulocytosis1
decreased hemoglobin content1
decreased erythrocyte cell number1
abnormal erythroblast morphology1
increased erythrocyte sodium:potassium-exchanging ATPase activity1

Additional cross-species homologs

Sequence homologs in species beyond Ensembl Compara’s model organisms, by Diamond local protein alignment (% sequence identity; best hit per species). Lower-identity rows are more distant homologs. The matched accessions’ gene symbols aren’t in biobtree yet, so each row shows the UniProt accession.

OrganismUniProtIdentityMethod
Bos taurusP3053594.1%Diamond
Ovis ariesQ9GMC994.1%Diamond
Sus scrofaQ6UN2782.2%Diamond
Canis lupus familiarisE2RDM972.1%Diamond
Chlorobaculum tepidum TLSQ8KBX247.1%Diamond

Genomic neighbors (locus context)

Genes flanking this one on the chromosome (NCBI/Entrez gene neighborhood). Positional context only — some neighbors share regulatory elements (bidirectional promoters, antisense/overlapping transcripts), but chromosomal adjacency is not itself a functional relationship (see Interactions for that).

SymbolTypeEntrez
UNC5CLprotein-coding222643
OARD1protein-coding221443
TREML1protein-coding340205
NFYAprotein-coding4800
APOBEC2protein-coding10930
TREM2protein-coding54209

Protein

Protein identifiers

Translocator protein 2 — Q5TGU0 (reviewed: Q5TGU0)

Alternative names: Peripheral-type benzodiazepine receptor-like protein 1

All UniProt accessions (1): Q5TGU0

UniProt curated annotations — full annotation on UniProt →

Function. Cholesterol-binding protein involved in the redistribution of cholesterol from lipid droplets to the endoplasmic reticulum. Required to meet cholesterol demands during erythropoietic differentiation. May play a role in transport processes at the plasma membrane of erythrocytes, including regulating VDAC-mediated ATP export, and import of the heme precursors protoporphyrin IX and 5-aminolevulinic acid.

Subunit / interactions. Homotetramer. May also form homodimer.

Subcellular location. Endoplasmic reticulum membrane. Cell membrane.

Tissue specificity. Expressed in erythrocytes (at protein level).

Domain organisation. The C-terminal region mediates cholesterol-binding.

Similarity. Belongs to the TspO/BZRP family.

Isoforms (2)

UniProt IDNamesCanonical?
Q5TGU0-11yes
Q5TGU0-22

RefSeq proteins (2): NP_001010873, NP_001153198 (=MANE)

Domains & families (InterPro)

IDNameType
IPR004307TspO_MBRFamily
IPR038330TspO/MBR-related_sfHomologous_superfamily

Pfam: PF03073

UniProt features (8 total): transmembrane region 5, splice variant 2, chain 1

Structure

Predicted structure (AlphaFold)

ModelpLDDTFraction very-high
AF-Q5TGU0-F168.090.00

Human Protein Atlas

Protein class: Transporters, Predicted membrane proteins, Predicted intracellular proteins

Protein evidence: Evidence at protein level

Subcellular location (HPA, imaging): plasma membrane

Antibody reliability (HPA): IF enhanced

Function

Pathways and Gene Ontology

Reactome pathways

0 curated (TAS) of 0; 0 disease pathways. Curated-first; evidence = TAS (manually curated) vs IEA (electronic inference).

MSigDB gene sets: 119 (showing top): GOBP_MYELOID_CELL_DIFFERENTIATION, MORF_RAGE, GOBP_MYELOID_CELL_HOMEOSTASIS, GOBP_ERYTHROCYTE_HOMEOSTASIS, GOBP_AMINO_ACID_TRANSMEMBRANE_TRANSPORT, GNF2_ANK1, GOBP_ORGANIC_ACID_TRANSPORT, GOBP_ORGANIC_HYDROXY_COMPOUND_TRANSPORT, GOBP_AMINO_ACID_TRANSPORT, GOBP_ORGANIC_ANION_TRANSPORT, GOCC_MITOCHONDRIAL_ENVELOPE, GNF2_SPTA1, GNF2_PCAF, TANAKA_METHYLATED_IN_ESOPHAGEAL_CARCINOMA, GOBP_MONOCARBOXYLIC_ACID_TRANSPORT

GO Biological Process (5): intracellular cholesterol transport (GO:0032367), lipid droplet organization (GO:0034389), enucleate erythrocyte differentiation (GO:0043353), import across plasma membrane (GO:0098739), 5-aminolevulinic acid import across plasma membrane (GO:0140484)

GO Molecular Function (3): cholesterol binding (GO:0015485), 5-aminolevulinic acid transmembrane transporter activity (GO:0140485), protein binding (GO:0005515)

GO Cellular Component (6): mitochondrial outer membrane (GO:0005741), endoplasmic reticulum (GO:0005783), endoplasmic reticulum membrane (GO:0005789), plasma membrane (GO:0005886), organelle membrane (GO:0031090), membrane (GO:0016020)

GO top-level categories

28 GO namespaces:

CategoryTerms
membrane2
intracellular anatomical structure1
cholesterol transport1
intracellular sterol transport1
organelle organization1
erythrocyte differentiation1
transmembrane transport1
import into cell1
monocarboxylic acid transport1
nitrogen compound transport1
amino acid import across plasma membrane1
carboxylic acid transmembrane transport1
sterol binding1
alcohol binding1
monocarboxylic acid transmembrane transporter activity1
amino acid transmembrane transporter activity1
binding1
mitochondrial membrane1
organelle outer membrane1
cytoplasm1
endomembrane system1
intracellular membrane-bounded organelle1
organelle membrane1
nuclear outer membrane-endoplasmic reticulum membrane network1
endoplasmic reticulum subcompartment1
cell periphery1
membrane-bounded organelle1
cellular anatomical structure1

Experimentally-supported GO annotations

GO terms backed by direct experimental evidence (ECO experimental codes) — 5 of 14 annotations. The rest are phylogenetic / computational / electronic (IEA).

5 experimentally-supported GO terms:

GO termNSEvidence
5-aminolevulinic acid import across plasma membraneBPmutant phenotype
import across plasma membraneBPdirect assay
organelle membraneCCdirect assay
plasma membraneCCdirect assay
5-aminolevulinic acid transmembrane transporter activityMFmutant phenotype

Protein interactions and networks

STRING

showing 15 of 1,095 interactions by confidence (×1000):

Protein AProtein BPartner UniProtScore
TSPO2HBMQ6B0K9551
TSPO2FAM174BQ3ZCQ3471
TSPO2EPS8L1Q8TE68463
TSPO2STARP49675463
TSPO2HBQ1P09105415
TSPO2KLF1Q13351388
TSPO2CRYGNQ8WXF5378
TSPO2GYPBP06028377
TSPO2GYPEP15421372
TSPO2LCP2Q13094370
TSPO2LRP2P98164346
TSPO2GYPAP02724340
TSPO2UNC5AQ6ZN44339
TSPO2TSPOP30536337
TSPO2SLC4A1P02730335

IntAct

Human interaction partners of TSPO2 in IntAct, one row per partner (best MIscore; records = supporting IntAct interaction records).

showing 30 of 55 partners by confidence:

PartnerInteraction typeMIscoreRecords
CREB3L1physical association0.5605
RETREG3physical association0.5605
AHNAK2physical association0.5603
AQP6physical association0.5603
ARL13Bphysical association0.5603
ASGR2physical association0.5603
ASZ1physical association0.5603
BIKphysical association0.5603
CD53physical association0.5603
CD69physical association0.5603
CD79Aphysical association0.5603
CERS4physical association0.5603
CLDN4physical association0.5603
CNR2physical association0.5603
COL4A5physical association0.5603
CPLX4physical association0.5603
DKK4physical association0.5603
EBPphysical association0.5603
EFNA5physical association0.5603
EMP1physical association0.5603
ERGIC3physical association0.5603
ERP29physical association0.5603
FCGR1Aphysical association0.5603
FFAR2physical association0.5603
FNDC9physical association0.5603
FXYD3physical association0.5603
GGT7physical association0.5603
GJB5physical association0.5603
GPR152physical association0.5603
GPR42physical association0.5603

BioGRID (62 interactions; top human partners by supporting records): AHNAK2 (Two-hybrid), AQP6 (Two-hybrid), ARL13B (Two-hybrid), ASGR2 (Two-hybrid), ASZ1 (Two-hybrid), BIK (Two-hybrid), C10orf54 (Two-hybrid), CD53 (Two-hybrid), CD69 (Two-hybrid), CD79A (Two-hybrid), CERS4 (Two-hybrid), CLDN4 (Two-hybrid), CNR2 (Two-hybrid), COL4A5 (Two-hybrid), CPLX4 (Two-hybrid)

SIGNOR signaling

2 signaling interactions:

AEffectBMechanism
TSPO2“up-regulates activity”SLC25A4binding
TSPO2“up-regulates activity”VDAC1binding

Disease & clinical

Genetic variants

Variant evidence for TSPO2: 20 ClinVar records (0 pathogenic / likely pathogenic); 2 GWAS associations.

ClinVar

20 variants total. Per-class counts are floors (≥ shown; pagination cap):

ClassificationCount (floor)
Pathogenic0
Likely pathogenic0
Uncertain significance14
Likely benign2
Benign0

SpliceAI

Top 10 splice-impact sites by Δscore (adjacent positions with the same effect merged into one range; 19 predictions of 307):

Position(s)EffectΔscoreSites
6:41043938–41043939acceptor_loss0.97006
6:41043159–41043160donor_loss0.96005
6:41043933acceptor_loss0.9500
6:41043160donor_loss0.9400
6:41043163donor_loss0.9400
6:41042775donor_gain0.9300
6:41043163donor_loss0.9000
6:41043163donor_loss0.8800
6:41043937acceptor_loss0.8600
6:41042768donor_gain0.8500

AlphaMissense

98 missense substitutions predicted likely pathogenic (of 1,064 scored), across 48 residues. Top 20 hotspot residues, ranked by the number of likely-pathogenic substitutions (of those reachable by a single-nucleotide change), then by mean score:

ResidueLikely-pathogenic substitutionsMean am_pathogenicityMax am_pathogenicity
W12450.7710.890
G5840.8000.897
W14140.7500.891
G1540.7410.844
W9140.7360.859
W6540.6830.717
W15340.6830.732
S9030.9210.921
S11930.8860.886
F830.7990.799
G11530.7620.777
P13730.7460.836
S6130.6900.739
F9730.6820.682
F9830.6760.676
N12830.6170.654
A6020.7590.805
P1220.6820.683
V6420.6770.788
L14220.6770.726

HPA cancer prognostics

RNA cancer specificity: Cancer enhanced (Liver Hepatocellular Carcinoma)

Disease associations

OMIM: gene MIM:619409 | disease phenotypes:

GWAS associations

2 associations:

StudyTraitp-value
GCST003007_1Non-cardia gastric cancer3e-8
GCST003010_4Gastric cancer7e-8

Drugs & pharmacology

Drug and pharmacology data

Is drug target: no

PharmGKB: 1 entry (CPIC guideline: no)

CTD chemical–gene interactions

9 total (human), top 9 by PubMed support.

ChemicalActions (top 5)PubMed papers
pirinixic acidaffects binding, decreases expression, increases activity1
perfluorooctanoic acidaffects cotreatment, decreases expression1
perfluorooctane sulfonic acidaffects cotreatment, decreases expression1
perfluorohexanesulfonic acidaffects cotreatment, decreases expression1
theaflavin-3,3’-digallateaffects expression1
Resveratrolaffects cotreatment, decreases expression1
Benzo(a)pyreneincreases methylation1
Plant Extractsaffects cotreatment, decreases expression1
Cyclosporineincreases expression1

Clinical trials (associated diseases)

Via MONDO — disease-level, not drug-specific.

  • Disease cohort memberships (association, not causation — diseases whose associated-gene cohort lists this gene; a subset are also under Associated diseases): gastric carcinoma