IBSP (Integrin Binding Sialoprotein)
Gene encoding a bone matrix sialoprotein involved in mineralization and cell adhesion
Gene Information Card
| Symbol | IBSP |
|---|---|
| Full Name | Integrin Binding Sialoprotein |
| Gene Type | protein-coding |
| Chromosomal Location | 4q22.1 |
| NCBI Gene ID | 3381 ncbi.nlm.nih.gov/gene/3381 |
| Ensembl ID | ENSG00000029559 |
| UniProt ID | P21815 |
| OMIM ID | 147563 |
| HGNC ID | 5341 |
| Aliases | BSP, BSP-II, SP-II, bone sialoprotein II |
Description
IBSP (Integrin Binding Sialoprotein) encodes bone sialoprotein II (BSP-II), a highly phosphorylated and sulfated glycoprotein that is a major component of the mineralized bone matrix. It binds to hydroxyapatite and mediates cell adhesion through integrin receptors, playing a critical role in bone mineralization, osteoblast differentiation, and bone remodeling. Expression is largely restricted to mineralized tissues.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Osteogenesis Imperfecta | Mutations in IBSP disrupt bone matrix integrity and mineralization, leading to brittle bones. | ClinVar; OMIM #147563 |
| Breast Cancer Bone Metastasis | Overexpression of IBSP in breast cancer cells promotes adhesion to bone matrix and osteoclast activation, facilitating metastatic colonization. | NCBI Gene; PubMed studies |
| Periodontal Disease | Reduced IBSP expression in periodontal ligament cells impairs cementum and alveolar bone regeneration. | NCBI Gene; literature review |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Bone | 127.3 | High |
| Cartilage | 45.6 | Medium |
| Adipose | 2.1 | Low |
| Lung | 0.8 | Not detected |
| Liver | 0.3 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| Saos-2 (osteosarcoma) | 89.5 | High expression; osteoblast-like |
| MG-63 (osteosarcoma) | 34.2 | Moderate expression |
| MCF-7 (breast cancer) | 12.1 | Low expression; bone metastasis model |
| HEK293 (embryonic kidney) | 0.5 | Not detected |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1A>G (p.Met1?) | missense | <0.01% | Loss of start codon; likely loss of function |
| c.742C>T (p.Arg248Trp) | missense | <0.01% | Altered integrin binding; associated with osteogenesis imperfecta |
| c.1030G>A (p.Gly344Ser) | missense | <0.01% | Reduced hydroxyapatite binding |
Mutation functional classification
Loss of Function (LOF)
Mutations affecting the start codon or critical integrin-binding RGD domain lead to loss of cell adhesion and mineralization function.
Gain of Function (GOF)
Not described for IBSP.
Dominant Negative (DN)
Not described for IBSP.
View complete mutation data：
Gene Ontology (GO)
Pathways
• Integrin signaling pathway (Reactome R-HSA-354192)
• Extracellular matrix organization (Reactome R-HSA-1474244)
• Osteoclast differentiation (KEGG hsa04380)
Protein Summary
Bone sialoprotein II (BSP-II) is a 317-amino acid secreted phosphoprotein with an RGD integrin-binding motif. It is heavily post-translationally modified (phosphorylation, sulfation, glycosylation) and binds to hydroxyapatite via glutamic acid-rich regions. BSP-II promotes osteoblast attachment and mineralization, and is upregulated in breast cancer bone metastases.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| IBSP Knockout HEK293 Cell Line | EDJ-KQ3675 | Human | 3381 | Details Get a Quote |
| IBSP Knockout HeLa Cell Line | EDJ-KQ53601 | Human | 3381 | Details Get a Quote |
| IBSP Knockout A-549 Cell Line | EDJ-KQ62068 | Human | 3381 | Details Get a Quote |
| IBSP Knockout HCT 116 Cell Line | EDJ-KQ70551 | Human | 3381 | Details Get a Quote |
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