Seroatlas · Human Serome Atlas

C9orf78

Splicing factor C9orf78

Also known as: CSU2, HCA59, HSPC220, TLS1_HUMAN

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

Protein identityUniProt · HPA

UniProt accession: Q9NZ63
Gene: C9orf78
Ensembl: ENSG00000136819
Chromosome: 9
Canonical length: 289 aa
Protein class: Predicted intracellular proteins
Subcellular location: Nucleoplasm

OverviewNCBI Gene

Enables U5 snRNA binding activity. Involved in mRNA cis splicing, via spliceosome and regulation of homologous chromosome segregation. Located in chromosome, centromeric region; cytosol; and nucleoplasm. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

289 residues, UniProt reviewed canonical sequence.

>Q9NZ63|C9orf78
     1  MPVVRKIFRR RRGDSESEED EQDSEEVRLK LEETREVQNL RKRPNGVSAV ALLVGEKVQE
    61  ETTLVDDPFQ MKTGGMVDMK KLKERGKDKI SEEEDLHLGT SFSAETNRRD EDADMMKYIE
   121  TELKKRKGIV EHEEQKVKPK NAEDCLYELP ENIRVSSAKK TEEMLSNQML SGIPEVDLGI
   181  DAKIKNIIST EDAKARLLAE QQNKKKDSET SFVPTNMAVN YVQHNRFYHE ELNAPIRRNK
   241  EEPKARPLRV GDTEKPEPER SPPNRKRPAN EKATDDYHYE KFKKMNRRY

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against C9orf78 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: Intracellular
Secreted: No
Transmembrane segments: 0
Mean surface accessibility (rSASA): 0.59
Highest tissue expression: 107 nTPM

Expression across tissuesHPA

Tissue

bone marrow: 107 nTPM
skeletal muscle: 66 nTPM
basal ganglia: 65 nTPM
midbrain: 63 nTPM
amygdala: 63 nTPM
spinal cord: 63 nTPM

Single-cell type

epididymal clear cells: 339 nCPM
erythrocytes: 275 nCPM
oocytes: 221 nCPM
megakaryocytes: 167 nCPM
differentiating spermatogonia: 158 nCPM
respiratory ionocytes: 158 nCPM

Immune cell

eosinophil: 218 nTPM
T-reg: 184 nTPM
naive CD4 T-cell: 174 nTPM
non-classical monocyte: 172 nTPM
basophil: 163 nTPM
memory CD8 T-cell: 163 nTPM

Brain region

hypothalamus: 38 nTPM
cerebral cortex: 37 nTPM
white matter: 37 nTPM
medulla oblongata: 36 nTPM
midbrain: 36 nTPM
thalamus: 35 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
gnomAD pLI: 0
gnomAD missense Z: 1.82
DepMap mean gene effect: -0.34
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

U5 snRNA binding

Cellular components

Protein domainsUniProt · Pfam · InterPro

Telomere length and silencing protein 1-like
Hepatocellular carcinoma-associated antigen 59

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of C9orf78 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 C9orf78 as an antibody target. Whether an autoantibody or antibody against C9orf78 could matter depends on whether native C9orf78 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

C9orf78 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 C9orf78 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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