CAPZB Gene - Capping Actin Protein of Muscle Z-Line Subunit Beta
Essential regulator of actin filament dynamics and sarcomere organization
Gene Information Card
| Symbol | CAPZB |
|---|---|
| Full Name | Capping Actin Protein of Muscle Z-Line Subunit Beta |
| Gene Type | protein-coding |
| Chromosomal Location | 1p36.13 |
| NCBI Gene ID | 832 ncbi.nlm.nih.gov/gene/832 |
| Ensembl ID | ENSG00000117461 |
| UniProt ID | P47756 |
| OMIM ID | 601572 |
| HGNC ID | 1491 |
| Aliases | CAPB, CPB2, CAPZ, capping protein beta |
Description
The CAPZB gene encodes the beta subunit of the actin-capping protein, a heterodimeric complex that binds to the barbed ends of actin filaments, preventing further polymerization and depolymerization. This regulation is critical for maintaining actin filament length and dynamics, particularly in muscle sarcomeres where it anchors actin filaments at the Z-line. CAPZB is expressed in multiple isoforms, with muscle-specific variants playing key roles in striated muscle structure and function.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Nemaline myopathy 8 | Disruption of actin filament capping leads to abnormal sarcomere assembly and muscle weakness | OMIM #615731 |
| Dilated cardiomyopathy | Impaired actin dynamics in cardiac myocytes reduces contractile function | ClinVar |
| Hypertrophic cardiomyopathy | Altered Z-line integrity contributes to myocardial hypertrophy | ClinVar |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Skeletal muscle | 78.5 | High |
| Heart | 62.3 | High |
| Brain | 18.2 | Medium |
| Liver | 12.1 | Medium |
| Kidney | 9.8 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| RH-30 (rhabdomyosarcoma) | 85.2 | Muscle lineage |
| H9c2 (cardiomyoblast) | 70.1 | Cardiac model |
| HeLa | 15.4 | Cervical cancer |
| HEK293 | 12.7 | Embryonic kidney |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.517C>T (p.Arg173Trp) | Missense | Rare | Impaired actin binding; associated with nemaline myopathy |
| c.1A>G (p.Met1Val) | Start loss | Very rare | Loss of protein expression; dilated cardiomyopathy |
| c.832G>A (p.Gly278Arg) | Missense | Rare | Reduced capping activity; hypertrophic cardiomyopathy |
Mutation functional classification
Loss of Function (LOF)
Missense and start-loss mutations reduce or abolish actin-capping activity, leading to uncontrolled actin filament elongation and sarcomere disorganization.
Gain of Function (GOF)
No gain-of-function mutations reported.
Dominant Negative (DN)
Heterozygous missense variants may interfere with wild-type CAPZB function in the heterodimer, causing dominant-negative effects.
View complete mutation data：
Gene Ontology (GO)
| • actin filament capping | • barbed-end actin filament capping |
| • actin cytoskeleton organization | • muscle contraction |
| • Z-disc |
Pathways
• Regulation of actin cytoskeleton (KEGG: hsa04810)
• Cardiac muscle contraction (KEGG: hsa04260)
• Tight junction (KEGG: hsa04530)
Protein Summary
CAPZB encodes the beta subunit of the heterodimeric actin-capping protein (CapZ). The protein localizes to the barbed ends of actin filaments, where it regulates filament length and turnover. In muscle cells, CapZ anchors actin filaments at the Z-disc, maintaining sarcomere integrity. The beta subunit exists in multiple splice variants, including muscle-specific isoforms. Mutations in CAPZB disrupt actin dynamics and are linked to nemaline myopathy and cardiomyopathies.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| CAPZB Knockout HEK293 Cell Line | EDJ-KQ50173 | Human | 832 | Details Get a Quote |
| CAPZB Knockout HeLa Cell Line | EDJ-KQ52788 | Human | 832 | Details Get a Quote |
| CAPZB Knockout A-549 Cell Line | EDJ-KQ61257 | Human | 832 | Details Get a Quote |
| CAPZB Knockout HCT 116 Cell Line | EDJ-KQ69753 | Human | 832 | Details Get a Quote |
