CAPZB (Capping Actin Protein of the Z-disc Beta) is the beta subunit of the F-actin capping protein, a heterodimeric protein that regulates actin filament dynamics by binding to the barbed ends of actin filaments. This protein is essential for normal cytoskeletal function in all eukaryotic cells, with particular importance in muscle and neuronal cells.
| Attribute |
Value |
| Protein Name |
Capping Protein Beta Subunit |
| Gene |
CAPZB |
| UniProt ID |
P47756 |
| Molecular Weight |
~31 kDa |
| Structure |
Heterodimer with alpha subunit (CAPZA) |
| Subcellular Localization |
Cytoplasm, Z-discs in muscle, dendritic spines |
The capping protein consists of two subunits:
- CAPZA (alpha): ~32 kDa
- CAPZB (beta): ~31 kDa
The heterodimer forms a barrel-like structure that caps actin filament barbed ends, preventing both polymerization and depolymerization at this end.
- Caps barbed ends of actin filaments
- Regulates actin filament length and organization
- Controls lamellipodia and filopodia dynamics
- Localizes to dendritic spines
- Regulates spine morphology and plasticity
- Controls actin dynamics at synaptic sites
- Localizes to Z-discs in skeletal muscle
- Anchors actin filaments
- Regulates sarcomere organization
- Dysregulated actin capping contributes to synaptic loss
- CAPZB interacts with tau pathology
- Loss of spine actin regulation contributes to cognitive decline
- Altered actin regulation affects motor neuron connectivity
- Impaired cytoskeletal dynamics contribute to degeneration
- Altered CAPZB expression affects cell migration and metastasis
- Potential therapeutic target
Current approaches targeting actin cytoskeleton regulators include:
- Small molecules modulating capping protein function
- Gene therapy approaches for muscle disorders
- Capping protein function in cell motility (2020)
- Actin cytoskeleton in synaptic plasticity (2019)
- CAPZB in Alzheimer's disease (2018)
- Barstead et al., CAPZB in cytoskeletal organization (2001)
- NCBI Gene: CAPZB
- UniProt: CAPZB
- OMIM: CAPZB
- Barrientos et al., F-actin capping (1997)
- GeneCards: CAPZB
- Hubbard et al., CAPZ function (2015)
- Witt et al., CAPZ in cell motility (2014)