Seroatlas · Human Serome Atlas

CALHM4

Calcium homeostasis modulator protein 4

Also known as: C6orf78, CAHM4_HUMAN, FAM26D, FLJ32239

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

Protein identityUniProt · HPA

UniProt accession: Q5JW98
Gene: CALHM4
Ensembl: ENSG00000164451
Chromosome: 6
Canonical length: 314 aa
Protein class: Predicted intracellular proteins, Predicted membrane proteins, Transporters
Subcellular location: Plasma membrane

OverviewNCBI Gene

Predicted to enable monoatomic cation channel activity. Predicted to be involved in ATP export and monoatomic cation transmembrane transport. Predicted to be located in membrane. Predicted to be active in plasma membrane. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

314 residues, UniProt reviewed canonical sequence.

>Q5JW98|CALHM4
     1  MCPTLNNIVS SLQRNGIFIN SLIAALTIGG QQLFSSSTFS CPCQVGKNFY YGSAFLVIPA
    61  LILLVAGFAL RSQMWTITGE YCCSCAPPYR RISPLECKLA CLRFFSITGR AVIAPLTWLA
   121  VTLLTGTYYE CAASEFASVD HYPMFDNVSA SKREEILAGF PCCRSAPSDV ILVRDEIALL
   181  HRYQSQMLGW ILITLATIAA LVSCCVAKCC SPLTSLQHCY WTSHLQNERE LFEQAAEQHS
   241  RLLMMHRIKK LFGFIPGSED VKHIRIPSCQ DWKDISVPTL LCMGDDLQGH YSFLGNRVDE
   301  DNEEDRSRGI ELKP

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against CALHM4 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: 4
Mean surface accessibility (rSASA): 0.43
Highest tissue expression: 22 nTPM

Expression across tissuesHPA

Tissue

placenta: 22 nTPM
choroid plexus: 3.1 nTPM
skin: 2.7 nTPM
heart muscle: 0.3 nTPM
testis: 0.3 nTPM
kidney: 0.2 nTPM

Single-cell type

syncytiotrophoblasts: 104 nCPM
cytotrophoblasts: 37 nCPM
migrating cytotrophoblasts: 20 nCPM
podocytes: 9.5 nCPM
choroid plexus epithelial cells: 3 nCPM
undifferentiated spermatogonia: 2.7 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

choroid plexus: 2.3 nTPM
hypothalamus: 0.5 nTPM
cerebral cortex: 0.4 nTPM
amygdala: 0.2 nTPM
basal ganglia: 0.2 nTPM
hippocampal formation: 0.2 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): 1.67
gnomAD pLI: 0
DepMap mean gene effect: 0.08
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

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads CALHM4 as an antibody target. Whether an autoantibody or antibody against CALHM4 could matter depends on whether native CALHM4 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

CALHM4 is annotated at the cell surface, where native CALHM4 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 CALHM4 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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