BFSP1: Beaded Filament Structural Protein 1
A key intermediate filament protein in lens fiber cells, associated with cataract formation.
Gene Information Card
| Symbol | BFSP1 |
|---|---|
| Full Name | Beaded Filament Structural Protein 1 |
| Gene Type | Protein coding |
| Chromosomal Location | 20p12.1 |
| NCBI Gene ID | 631 ncbi.nlm.nih.gov/gene/631 |
| Ensembl ID | ENSG00000125864 |
| UniProt ID | Q13515 |
| OMIM ID | 603307 |
| HGNC ID | 1041 |
| Aliases | CP115, filensin, LIFL-L |
Description
BFSP1 encodes beaded filament structural protein 1, also known as filensin or CP115. This protein is a type of intermediate filament specifically expressed in lens fiber cells, where it forms beaded filaments essential for maintaining lens transparency and refractive index. Mutations in BFSP1 are associated with autosomal dominant cataract, particularly cortical and nuclear types.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Cataract 33 (CTRCT33) | Loss of BFSP1 function disrupts lens fiber cell cytoskeleton, leading to opacification. | OMIM #611391; ClinVar pathogenic variants |
| Cataract, autosomal dominant cortical | Missense or frameshift mutations impair filament assembly, causing dominant-negative effects. | ClinVar; PubMed studies |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Lens | High (nTPM ~2000) | Tissue-specific high expression |
| Retina | Low (nTPM ~5) | Minimal expression |
| Testis | Very low (nTPM ~1) | Trace expression |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| Lens epithelial cells (HLE-B3) | High | Model for lens biology |
| ARPE-19 (retinal pigment epithelium) | Low | Not a primary expression site |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.736C>T (p.Arg246*) | Nonsense | Rare | Loss of function; truncation |
| c.632delG (p.Gly211Alafs*22) | Frameshift | Rare | Loss of function; premature stop |
| c.1045G>A (p.Glu349Lys) | Missense | Rare | Dominant-negative; disrupts filament assembly |
Mutation functional classification
Loss of Function (LOF)
Nonsense and frameshift mutations (e.g., p.Arg246*, p.Gly211Alafs*22) lead to truncated protein and haploinsufficiency, causing cataract.
Gain of Function (GOF)
No evidence of gain-of-function mutations in BFSP1.
Dominant Negative (DN)
Missense mutations (e.g., p.Glu349Lys) produce defective filensin that interferes with wild-type filament assembly, causing dominant cataract.
View complete mutation data：
Gene Ontology (GO)
Pathways
• Intermediate filament organization (Reactome: R-HSA-6809371)
• Lens fiber cell differentiation (KEGG: hsa04310)
Protein Summary
BFSP1 encodes filensin (CP115), a 665-amino acid intermediate filament protein that co-assembles with BFSP2 (phakinin) to form beaded filaments in lens fiber cells. These filaments provide mechanical stability and maintain lens transparency. The protein contains a central alpha-helical rod domain flanked by non-helical head and tail domains. Mutations in BFSP1 cause cataract by disrupting filament assembly and lens cell architecture.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| BFSP1 Knockout HEK293 Cell Line | EDJ-KQ4132 | Human | 631 | Details Get a Quote |
| BFSP1 Knockout HCT 116 Cell Line | EDJ-KQ25215 | Human | 631 | Details Get a Quote |
| BFSP1 Knockout A-549 Cell Line | EDJ-KQ26550 | Human | 631 | Details Get a Quote |
| BFSP1 Knockout HeLa Cell Line | EDJ-KQ26552 | Human | 631 | Details Get a Quote |
