Seroatlas · Human Serome Atlas

CPNE9

Copine-9

Also known as: CPNE9_HUMAN, KIAA4217

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

Protein identityUniProt · HPA

UniProt accession: Q8IYJ1
Gene: CPNE9
Ensembl: ENSG00000144550
Chromosome: 3
Canonical length: 553 aa
Protein class: Predicted intracellular proteins
Subcellular location: Plasma membrane,Cytosol

OverviewNCBI Gene

Predicted to enable calcium-dependent phospholipid binding activity. Involved in positive regulation of dendrite extension. Located in extracellular exosome. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

553 residues, UniProt reviewed canonical sequence.

>Q8IYJ1|CPNE9
     1  MSLGGASERS VPATKIEITV SCRNLLDLDT FSKSDPMVVL YTQSRASQEW REFGRTEVID
    61  NTLNPDFVRK FVLDYFFEEK QNLRFDVYNV DSKTNISKPK DFLGQAFLAL GEVIGGQGSR
   121  VERTLTGVPG KKCGTILLTA EELSNCRDIA TMQLCANKLD KKDFFGKSDP FLVFYRSNED
   181  GTFTICHKTE VVKNTLNPVW QPFSIPVRAL CNGDYDRTVK IDVYDWDRDG SHDFIGEFTT
   241  SYRELSKAQN QFTVYEVLNP RKKCKKKKYV NSGTVTLLSF SVDSEFTFVD YIKGGTQLNF
   301  TVAIDFTASN GNPLQPTSLH YMSPYQLSAY AMALKAVGEI IQDYDSDKLF PAYGFGAKLP
   361  PEGRISHQFP LNNNDEDPNC AGIEGVLESY FQSLRTVQLY GPTYFAPVIN QVARAAAKIS
   421  DGSQYYVLLI ITDGVISDMT QTKEAIVSAS SLPMSIIIVG VGPAMFEAME ELDGDDVRVS
   481  SRGRYAERDI VQFVPFRDYV DRSGNQVLSM ARLAKDVLAE IPEQLLSYMR TRDIQPRPPP
   541  PANPSPIPAP EQP

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against CPNE9 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: Cell surface
Secreted: No
Transmembrane segments: 0
Mean surface accessibility (rSASA): 0.28
Highest tissue expression: 37 nTPM

Expression across tissuesHPA

Tissue

cerebellum: 37 nTPM
cerebral cortex: 26 nTPM
hypothalamus: 9.3 nTPM
midbrain: 6.1 nTPM
pituitary gland: 5.3 nTPM
basal ganglia: 2.9 nTPM

Single-cell type

late spermatids: 100 nCPM
brain excitatory neurons: 31 nCPM
early spermatids: 18 nCPM
other brain neurons: 16 nCPM
retinal ganglion cells: 12 nCPM
oocytes: 9.2 nCPM

Immune cell

intermediate monocyte: 1 nTPM
non-classical monocyte: 0.7 nTPM
plasmacytoid DC: 0.4 nTPM
classical monocyte: 0.3 nTPM
total PBMC: 0.1 nTPM
basophil: 0 nTPM

Brain region

pons: 150 nTPM
thalamus: 86 nTPM
medulla oblongata: 62 nTPM
hypothalamus: 45 nTPM
cerebral cortex: 45 nTPM
midbrain: 44 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): 0.71
gnomAD pLI: 0
gnomAD missense Z: 1.71
DepMap mean gene effect: 0.11
DepMap dependency class: none

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 3% 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

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads CPNE9 as an antibody target. Whether an autoantibody or antibody against CPNE9 could matter depends on whether native CPNE9 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

CPNE9 is annotated at the cell surface, where native CPNE9 is exposed to circulating antibodies and is a prime autoantibody target that could block, deplete, or overstimulate it.

Annotation status

The present source text does not explicitly label CPNE9 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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