ACP3: Acid Phosphatase 3 – Tartrate-Resistant Acid Phosphatase (TRAP)
ACP3 encodes tartrate-resistant acid phosphatase (TRAP), a key enzyme in bone resorption and iron metabolism, with implications in skeletal disorders and cancer.
Gene Information Card
| Symbol | ACP3 |
|---|---|
| Full Name | Acid phosphatase 3, tartrate resistant |
| Gene Type | Protein coding |
| Chromosomal Location | 19p13.2 |
| NCBI Gene ID | 54 ncbi.nlm.nih.gov/gene/54 |
| Ensembl ID | ENSG00000105669 |
| UniProt ID | P13686 |
| OMIM ID | 171640 |
| HGNC ID | 124 |
| Aliases | TRAP, TRACP, TR-AP, PAP, SPENCDI |
Description
ACP3 (acid phosphatase 3) encodes tartrate-resistant acid phosphatase (TRAP), a glycosylated metalloenzyme expressed primarily in osteoclasts, macrophages, and dendritic cells. TRAP catalyzes the hydrolysis of phosphate esters under acidic conditions and is resistant to inhibition by tartrate. It plays a critical role in bone resorption, iron transport, and immune regulation. Mutations in ACP3 cause spondyloenchondrodysplasia with immune dysregulation (SPENCDI), and altered expression is associated with osteoporosis, Gaucher disease, and certain cancers.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Spondyloenchondrodysplasia with immune dysregulation (SPENCDI) | Loss-of-function mutations in ACP3 impair TRAP activity, leading to defective bone remodeling and immune abnormalities. | OMIM #607944; PMID: 21129723 |
| Gaucher disease | Elevated TRAP activity in serum is a biomarker for Gaucher disease, reflecting macrophage activation. | ClinVar; PMID: 10737979 |
| Osteoporosis | Increased TRAP expression correlates with enhanced osteoclast activity and bone loss. | PMID: 12693595 |
| Breast cancer | TRAP overexpression in tumor-associated macrophages promotes metastasis and poor prognosis. | PMID: 21804531 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Bone marrow | 12.5 | Medium |
| Spleen | 8.3 | Medium |
| Lung | 5.1 | Low |
| Liver | 3.2 | Low |
| Whole blood | 1.8 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| Osteoclasts (primary) | 45.2 | High expression; key functional cell type |
| THP-1 (monocyte) | 22.1 | Differentiated to macrophages |
| MCF7 (breast cancer) | 3.4 | Low expression |
| HeLa (cervical cancer) | 2.1 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.155G>A (p.Arg52Gln) | Missense | Rare | Loss of TRAP enzymatic activity; associated with SPENCDI |
| c.511C>T (p.Arg171Trp) | Missense | Rare | Impaired protein stability; SPENCDI |
| c.1040_1042del (p.Phe347del) | Deletion | Rare | Frameshift; loss of function; SPENCDI |
Mutation functional classification
Loss of Function (LOF)
Missense and deletion mutations in ACP3 reduce or abolish TRAP enzymatic activity, leading to SPENCDI.
Gain of Function (GOF)
No gain-of-function mutations reported in ACP3.
Dominant Negative (DN)
No dominant-negative mutations reported; SPENCDI is autosomal recessive.
View complete mutation data：
Gene Ontology (GO)
| • GO:0003993 – acid phosphatase activity | • GO:0005737 – cytoplasm |
| • GO:0005764 – lysosome | • GO:0005886 – plasma membrane |
| • GO:0006879 – cellular iron ion homeostasis | • GO:0031402 – sodium ion transport |
| • GO:0045453 – bone resorption |
Pathways
• Osteoclast differentiation (KEGG hsa04380)
• Lysosome (KEGG hsa04142)
• Iron metabolism and transport (Reactome R-HSA-917937)
Protein Summary
Tartrate-resistant acid phosphatase (TRAP) is a 35 kDa metalloenzyme containing a binuclear iron center essential for catalytic activity. It exists as two isoforms (TRAP 5a and 5b) differing in glycosylation. TRAP 5b is secreted by osteoclasts and is a serum marker of bone resorption. The enzyme dephosphorylates osteopontin and other bone matrix proteins, facilitating osteoclast migration and bone degradation. In macrophages, TRAP participates in iron recycling by dephosphorylating transferrin receptor. Structural studies reveal a conserved active site with two iron ions coordinated by histidine and aspartate residues.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| ACP3 Knockout HEK293 Cell Line | EDJ-KQ2521 | Human | 55 | Details Get a Quote |
| ACP3 Knockout HeLa Cell Line | EDJ-KQ52538 | Human | 55 | Details Get a Quote |
| ACP3 Knockout A-549 Cell Line | EDJ-KQ61020 | Human | 55 | Details Get a Quote |
| ACP3 Knockout HCT 116 Cell Line | EDJ-KQ69495 | Human | 55 | Details Get a Quote |
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