LAMB3 Gene: Laminin Subunit Beta 3 – Function, Mutations, and Associated Diseases
Comprehensive guide to LAMB3, encoding laminin-332 beta 3 chain, its role in basement membrane integrity, and its link to junctional epidermolysis bullosa and cancer.
Gene Information Card
| Symbol | LAMB3 |
|---|---|
| Full Name | Laminin subunit beta 3 |
| Gene Type | Protein coding |
| Chromosomal Location | 1q32.2 |
| NCBI Gene ID | 3914 ncbi.nlm.nih.gov/gene/3914 |
| Ensembl ID | ENSG00000196878 |
| UniProt ID | Q13751 |
| OMIM ID | 150310 |
| HGNC ID | 6490 |
| Aliases | LAMNB1, Laminin B1k, Laminin beta 3 chain |
Description
The LAMB3 gene encodes the beta 3 chain of laminin-332 (formerly laminin-5), a heterotrimeric extracellular matrix protein composed of alpha 3, beta 3, and gamma 2 chains. Laminin-332 is a major component of the basement membrane in stratified squamous epithelia, where it mediates cell adhesion, migration, and signaling. Mutations in LAMB3 cause junctional epidermolysis bullosa, a severe skin blistering disorder. LAMB3 is also implicated in cancer progression and metastasis.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Junctional epidermolysis bullosa (JEB) | Loss-of-function mutations lead to truncated or absent beta 3 chain, disrupting laminin-332 assembly and basement membrane adhesion, causing skin fragility and blistering. | ClinVar, OMIM |
| Laryngo-onycho-cutaneous syndrome (LOCS) | Specific mutations in LAMB3 (e.g., c.31insC) cause a variant of JEB with laryngeal and nail involvement. | OMIM |
| Squamous cell carcinoma (SCC) | Overexpression of LAMB3 in tumor stroma promotes invasion and metastasis via integrin signaling. | COSMIC, PubMed |
| Breast cancer | LAMB3 upregulation correlates with poor prognosis and epithelial-mesenchymal transition (EMT). | COSMIC, PubMed |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Skin | High | High |
| Oral mucosa | High | High |
| Esophagus | High | High |
| Lung | Low | Low |
| Kidney | Low | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HaCaT (keratinocyte) | High | Basal keratinocytes |
| A431 (epidermoid carcinoma) | High | Overexpressed |
| MCF7 (breast cancer) | Moderate | Induced by EMT |
| HeLa (cervical cancer) | Low | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.31insC (p.Leu11ProfsTer20) | Frameshift | Common in JEB | Premature stop codon, loss of function |
| c.628G>A (p.Gly210Arg) | Missense | Rare | Disrupts protein folding |
| c.1903C>T (p.Arg635Ter) | Nonsense | Reported | Truncated protein |
| c.1700delA (p.Lys567ArgfsTer5) | Deletion | Rare | Frameshift, loss of function |
Mutation functional classification
Loss of Function (LOF)
Most LAMB3 mutations are loss-of-function, leading to reduced or absent laminin-332, causing JEB.
Gain of Function (GOF)
Not typically observed; overexpression in cancer is due to transcriptional upregulation, not activating mutations.
Dominant Negative (DN)
Rare; some missense mutations may exert dominant-negative effects by interfering with heterotrimer assembly.
View complete mutation data：
Gene Ontology (GO)
| • extracellular matrix structural constituent | • cell adhesion |
| • basement membrane organization | • integrin binding |
| • cell migration | • epithelial cell differentiation |
Pathways
• ECM-receptor interaction
• Focal adhesion
• PI3K-Akt signaling pathway
• Integrin signaling
Protein Summary
Laminin subunit beta 3 is a 140 kDa protein that, together with alpha 3 and gamma 2 chains, forms laminin-332. It contains N-terminal domains involved in self-assembly and a C-terminal coiled-coil domain that mediates chain association. The protein is crucial for hemidesmosome formation and epithelial cell anchoring to the basement membrane. Post-translational processing includes proteolytic cleavage of the C-terminus, which modulates cell adhesion and migration.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| LAMB3 Knockout HEK293 Cell Line | EDJ-KQ828 | Human | 3914 | Details Get a Quote |
| LAMB3 Knockout HeLa Cell Line | EDJ-KQ18328 | Human | 3914 | Details Get a Quote |
| LAMB3 Knockout A-549 Cell Line | EDJ-KQ19598 | Human | 3914 | Details Get a Quote |
| LAMB3 Knockout HCT 116 Cell Line | EDJ-KQ19599 | Human | 3914 | Details Get a Quote |
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