SAA4
Serum amyloid A-4 protein
Also known as: C-SAA, CSAA, SAA4_HUMAN
Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene
Protein identityUniProt · HPA
- UniProt accession
- P35542
- Gene
- SAA4
- Ensembl
- ENSG00000148965
- Chromosome
- 11
- Canonical length
- 130 aa
- Protein class
- Plasma proteins, Predicted secreted proteins
- Secretome location
- Secreted to blood
OverviewNCBI Gene
Predicted to be involved in acute-phase response. Located in extracellular exosome. [provided by Alliance of Genome Resources, Jul 2025]
Canonical amino-acid sequenceUniProt
130 residues, UniProt reviewed canonical sequence.
>P35542|SAA4
1 MRLFTGIVFC SLVMGVTSES WRSFFKEALQ GVGDMGRAYW DIMISNHQNS NRYLYARGNY
61 DAAQRGPGGV WAAKLISRSR VYLQGLIDCY LFGNSSTVLE DSKSNEKAEE WGRSGKDPDR
121 FRPDGLPKKYLocalizationUniProt · AlphaFold · HPA
Whether an antibody against SAA4 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)
- 0.35
- Highest tissue expression
- 2,068 nTPM
Expression across tissuesHPA
Tissue
- liver: 2,068 nTPM
- cervix: 15 nTPM
- salivary gland: 12 nTPM
- adipose tissue: 6.8 nTPM
- breast: 6.2 nTPM
- skeletal muscle: 3.3 nTPM
Single-cell type
- hepatocytes: 1,879 nCPM
- conjunctival goblet cells: 50 nCPM
- hepatic stellate cells: 26 nCPM
- lacrimal acinar cells: 21 nCPM
- submucosal glandular cells: 14 nCPM
- salivary ionocytes: 10 nCPM
Immune cell
- memory B-cell: 0.2 nTPM
- basophil: 0 nTPM
- classical monocyte: 0 nTPM
- eosinophil: 0 nTPM
- gdT-cell: 0 nTPM
- intermediate monocyte: 0 nTPM
Brain region
- white matter: 0.4 nTPM
- cerebral cortex: 0.3 nTPM
- medulla oblongata: 0.3 nTPM
- midbrain: 0.3 nTPM
- thalamus: 0.3 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)
- 1.69
- gnomAD pLI
- 0.01
- gnomAD missense Z
- -0.3
- DepMap mean gene effect
- 0.04
- 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
Cellular components
Protein domainsUniProt · Pfam · InterPro
KeywordsUniProt
Antibody and autoantibody relevanceSeroatlas analysis
Seroatlas reads SAA4 as an antibody target. Whether an autoantibody or antibody against SAA4 could matter depends on whether native SAA4 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.
SAA4 is annotated as secreted, so native SAA4 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 SAA4 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.
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