Seroatlas · Human Serome Atlas

SBSPON

Somatomedin-B and thrombospondin type-1 domain-containing protein

Also known as: C8orf84, RPESP, SBSPO_HUMAN

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

Protein identityUniProt · HPA

UniProt accession: Q8IVN8
Gene: SBSPON
Ensembl: ENSG00000164764
Chromosome: 8
Canonical length: 264 aa
Protein class: Predicted secreted proteins
Subcellular location: Vesicles
Secretome location: Secreted to extracellular matrix

OverviewNCBI Gene

Predicted to be an extracellular matrix structural constituent. Located in collagen-containing extracellular matrix. [provided by Alliance of Genome Resources, Apr 2025]

Canonical amino-acid sequenceUniProt

264 residues, UniProt reviewed canonical sequence.

>Q8IVN8|SBSPON
     1  MRTLWMALCA LSRLWPGAQA GCAEAGRCCP GRDPACFARG WRLDRVYGTC FCDQACRFTG
    61  DCCFDYDRAC PARPCFVGEW SPWSGCADQC KPTTRVRRRS VQQEPQNGGA PCPPLEERAG
   121  CLEYSTPQGQ DCGHTYVPAF ITTSAFNKER TRQATSPHWS THTEDAGYCM EFKTESLTPH
   181  CALENWPLTR WMQYLREGYT VCVDCQPPAM NSVSLRCSGD GLDSDGNQTL HWQAIGNPRC
   241  QGTWKKVRRV DQCSCPAVHS FIFI

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SBSPON 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: Secreted
Secreted: Yes
Transmembrane segments: 0
Mean surface accessibility (rSASA): 0.36
Highest tissue expression: 21 nTPM

Expression across tissuesHPA

Tissue

blood vessel: 21 nTPM
urinary bladder: 16 nTPM
prostate: 14 nTPM
seminal vesicle: 11 nTPM
stomach: 9.5 nTPM
placenta: 9.1 nTPM

Single-cell type

podocytes: 315 nCPM
schwann cells: 114 nCPM
smooth muscle cells: 111 nCPM
vascular smooth muscle cells: 94 nCPM
mucous neck cells: 82 nCPM
epididymal efferent duct absorptive cells: 72 nCPM

Immune cell

basophil: 0.1 nTPM
naive CD8 T-cell: 0.1 nTPM
neutrophil: 0.1 nTPM
NK-cell: 0.1 nTPM
plasmacytoid DC: 0.1 nTPM
classical monocyte: 0 nTPM

Brain region

white matter: 36 nTPM
spinal cord: 19 nTPM
medulla oblongata: 18 nTPM
pons: 8 nTPM
cerebellum: 4.8 nTPM
midbrain: 4.2 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): 1.16
gnomAD pLI: 0
gnomAD missense Z: -0.06
DepMap mean gene effect: 0.03
DepMap dependency class: none

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

Cellular components

extracellular matrix

Protein domainsUniProt · Pfam · InterPro

Thrombospondin type-1 (TSP1) repeat
Somatomedin B domain
Somatomedin B-like domain superfamily
Thrombospondin type-1 repeat superfamily
Spondin-like TSP1 domain
Spondin-like TSP1 domain
Somatomedin-B and thrombospondin type-1 domain-containing protein
SBSPON-like, C-terminal
SBSPON-like, C-terminal

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

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

SBSPON is annotated as secreted, so native SBSPON circulates and is directly accessible to antibodies. Secreted and cell-surface proteins are the autoantibody targets most likely to act like drugs, blocking or depleting the native protein.

Annotation status

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

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