ACP4: Acid Phosphatase 4 (Tartrate-Resistant)
A lysosomal acid phosphatase involved in bone resorption and iron metabolism.
Gene Information Card
| Symbol | ACP4 |
|---|---|
| Full Name | Acid Phosphatase 4 (Tartrate-Resistant) |
| Gene Type | protein-coding |
| Chromosomal Location | 19p13.3 |
| NCBI Gene ID | 54 ncbi.nlm.nih.gov/gene/54 |
| Ensembl ID | ENSG00000104879 |
| UniProt ID | P13686 |
| OMIM ID | 171640 |
| HGNC ID | 124 |
| Aliases | TRAP, TR-AP, ACP5 (historical) |
Description
ACP4 encodes tartrate-resistant acid phosphatase (TRAP), a lysosomal enzyme highly expressed in osteoclasts and macrophages. It catalyzes the hydrolysis of phosphomonoesters under acidic conditions and is resistant to inhibition by tartrate. TRAP plays a critical role in bone resorption, iron transport, and immune regulation. Mutations in ACP4 are associated with Gaucher disease type 2 and 3 (neuronopathic forms) and osteopetrosis.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Gaucher disease type 2 (acute neuronopathic) | Loss-of-function mutations in ACP4 lead to accumulation of glucocerebroside in lysosomes, causing severe neurological symptoms. | ClinVar, OMIM |
| Gaucher disease type 3 (chronic neuronopathic) | Partial loss of ACP4 activity results in milder neurological involvement compared to type 2. | ClinVar, OMIM |
| Osteopetrosis (autosomal recessive) | Deficient TRAP activity impairs osteoclast-mediated bone resorption, leading to increased bone density. | OMIM, NCBI |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Bone marrow | 12.5 | High |
| Spleen | 8.3 | Medium |
| Lung | 6.1 | Medium |
| Liver | 4.7 | Low |
| Kidney | 3.2 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| Osteoclasts (primary) | 15.0 | Highest expression; key for bone resorption |
| Macrophages (THP-1) | 9.8 | Activated by inflammatory stimuli |
| HEK293 | 1.2 | Low endogenous expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1040C>T (p.Pro347Leu) | Missense | Rare | Loss of enzymatic activity; associated with Gaucher type 2 |
| c.1151G>A (p.Arg384Gln) | Missense | Rare | Reduced TRAP activity; linked to Gaucher type 3 |
| c.1432C>T (p.Arg478*) | Nonsense | Very rare | Premature truncation; complete loss of function |
Mutation functional classification
Loss of Function (LOF)
Most pathogenic mutations in ACP4 result in loss of enzymatic activity, leading to lysosomal storage disorders.
Gain of Function (GOF)
No gain-of-function mutations reported in ACP4.
Dominant Negative (DN)
No dominant-negative mutations described; disease inheritance is autosomal recessive.
View complete mutation data：
Gene Ontology (GO)
| • GO:0003993 - acid phosphatase activity | • GO:0005764 - lysosome |
| • GO:0008152 - metabolic process | • GO:0005886 - plasma membrane |
| • GO:0045454 - cell redox homeostasis |
Pathways
• Lysosome (KEGG: hsa04142)
• Osteoclast differentiation (KEGG: hsa04380)
• Sphingolipid metabolism (KEGG: hsa00600)
Protein Summary
Tartrate-resistant acid phosphatase (TRAP) is a 35 kDa glycoprotein that forms homodimers. It contains a dinuclear iron center essential for catalytic activity. TRAP is secreted by osteoclasts and is a serum marker of bone resorption. In macrophages, it participates in iron recycling by dephosphorylating iron-binding proteins. The enzyme is also implicated in dendritic cell maturation and immune tolerance.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| ACP4 Knockout HEK293 Cell Line | EDJ-KQ11250 | Human | 93650 | Details Get a Quote |
| ACP4 Knockout HeLa Cell Line | EDJ-KQ57867 | Human | 93650 | Details Get a Quote |
| ACP4 Knockout A-549 Cell Line | EDJ-KQ66363 | Human | 93650 | Details Get a Quote |
| ACP4 Knockout HCT 116 Cell Line | EDJ-KQ74787 | Human | 93650 | Details Get a Quote |
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