SPACA5
Sperm acrosome-associated protein 5
Also known as: dJ54B20.3, LYC5, LYZL5, LYZL5_HUMAN, LYZL5B, PNPK6288, SLLP2, SPACA5B, UNQ6288
Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene
Protein identityUniProt · HPA
- UniProt accession
- Q96QH8
- Gene
- SPACA5
- Ensembl
- ENSG00000171489
- Chromosome
- X
- Canonical length
- 159 aa
- Protein class
- Enzymes, Predicted secreted proteins
- Secretome location
- Secreted in male reproductive system
OverviewNCBI Gene
Predicted to enable lysozyme activity. Predicted to be involved in fusion of sperm to egg plasma membrane involved in single fertilization. Predicted to be located in extracellular region. Predicted to be active in acrosomal vesicle and sperm flagellum. [provided by Alliance of Genome Resources, Jul 2025]
Canonical amino-acid sequenceUniProt
159 residues, UniProt reviewed canonical sequence.
>Q96QH8|SPACA5
1 MKAWGTVVVT LATLMVVTVD AKIYERCELA ARLERAGLNG YKGYGVGDWL CMAHYESGFD
61 TAFVDHNPDG SSEYGIFQLN SAWWCDNGIT PTKNLCHMDC HDLLNRHILD DIRCAKQIVS
121 SQNGLSAWTS WRLHCSGHDL SEWLKGCDMH VKIDPKIHPLocalizationUniProt · AlphaFold · HPA
Whether an antibody against SPACA5 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
- 34 nTPM
Expression across tissuesHPA
Tissue
- testis: 34 nTPM
- choroid plexus: 0.3 nTPM
- epididymis: 0.2 nTPM
- midbrain: 0.2 nTPM
- skin: 0.2 nTPM
- amygdala: 0.1 nTPM
Single-cell type
- early spermatids: 0.3 nCPM
- cardiomyocytes: 0.2 nCPM
- adipocytes: 0 nCPM
- adrenal cortex cells: 0 nCPM
- adrenal medulla cells: 0 nCPM
- alveolar cells type 1: 0 nCPM
Immune cell
- T-reg: 0.3 nTPM
- basophil: 0 nTPM
- classical monocyte: 0 nTPM
- eosinophil: 0 nTPM
- gdT-cell: 0 nTPM
- intermediate monocyte: 0 nTPM
Brain region
- cerebral cortex: 0.8 nTPM
- midbrain: 0.6 nTPM
- pons: 0.6 nTPM
- thalamus: 0.6 nTPM
- cerebellum: 0.5 nTPM
- hypothalamus: 0.5 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)
- 1.71
- gnomAD pLI
- 0.4
- gnomAD missense Z
- 0.85
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
Cellular components
Protein domainsUniProt · Pfam · InterPro
KeywordsUniProt
Antibody and autoantibody relevanceSeroatlas analysis
Seroatlas reads SPACA5 as an antibody target. Whether an autoantibody or antibody against SPACA5 could matter depends on whether native SPACA5 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.
SPACA5 is annotated as secreted, so native SPACA5 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 SPACA5 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.
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