Seroatlas · Human Serome Atlas

C20orf173

Uncharacterized protein C20orf173

Also known as: CT173_HUMAN, dJ477O4.4

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

Protein identityUniProt · HPA

UniProt accession: Q96LM9
Gene: C20orf173
Ensembl: ENSG00000125975
Chromosome: 20
Canonical length: 149 aa
Protein class: Predicted intracellular proteins
Subcellular location: Nucleoplasm,Vesicles,Plasma membrane

OverviewNCBI Gene

Predicted to enable beta-galactoside (CMP) alpha-2,3-sialyltransferase activity. Predicted to be involved in ganglioside biosynthetic process via lactosylceramide; protein glycosylation; and sialylation. Predicted to be active in membrane. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

149 residues, UniProt reviewed canonical sequence.

>Q96LM9|C20orf173
     1  MLSGPHPSPT FRPNPCPWPC LHSLWMEISP TQLCFLSPGP SPQSPSCCFQ GMNSGSELGK
    61  LWRKLFKGIP RLSVSHFDFY CGTCVLLGRP QIPQGSSLGN DIDQYPVVFR NASDQGSWMQ
   121  LEMLLRKLSD LVWTSDALSD KILEDGLVP

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against C20orf173 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: Unknown
Secreted: No
Transmembrane segments: 0
Mean surface accessibility (rSASA): 0.56
Highest tissue expression: 34 nTPM

Expression across tissuesHPA

Tissue

testis: 34 nTPM
retina: 0.1 nTPM
skin: 0.1 nTPM
adipose tissue: 0 nTPM
adrenal gland: 0 nTPM
amygdala: 0 nTPM

Single-cell type

early spermatids: 504 nCPM
late spermatids: 149 nCPM
late primary spermatocytes: 39 nCPM
leydig cells: 0.9 nCPM
peritubular myoid cells: 0.3 nCPM
undifferentiated spermatogonia: 0.3 nCPM

Immune cell

basophil: 0 nTPM
classical monocyte: 0 nTPM
eosinophil: 0 nTPM
gdT-cell: 0 nTPM
intermediate monocyte: 0 nTPM
MAIT T-cell: 0 nTPM

Brain region

cerebellum: 3.2 nTPM
cerebral cortex: 2.8 nTPM
basal ganglia: 1.9 nTPM
white matter: 1.4 nTPM
amygdala: 1.2 nTPM
hippocampal formation: 1.1 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): 1.44
gnomAD pLI: 0
gnomAD missense Z: 1.28
DepMap mean gene effect: 0.08
DepMap dependency class: selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 6% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

sialylation

Molecular functions

3-sialyltransferase activity
beta-galactoside (CMP) alpha-2

Cellular components

membrane

Protein domainsUniProt · Pfam · InterPro

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads C20orf173 as an antibody target. Whether an autoantibody or antibody against C20orf173 could matter depends on whether native C20orf173 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

C20orf173 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 C20orf173 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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