Recombinant Proteins
Product List
CAPG Human
Capping Protein Gelsolin-Like Human Recombinant
CAPZA2 Human
Capping Protein (Actin Filament) Muscle Z-Line Alpha 2 Human Recombinant
CAPZA2 is fused to a 23 amino acid His-tag at N-terminus & purified by proprietary chromatographic techniques.
Introduction
Capping protein (CP) is a heterodimeric protein that binds to the barbed (fast-growing) ends of actin filaments, thereby regulating actin filament assembly and disassembly . It is composed of two subunits, typically referred to as α and β subunits . CP is highly conserved across eukaryotic species and is known by various names, including β-actinin, CapZ, and Cap32/34 .
Key Biological Properties: Capping proteins have a high affinity for the barbed ends of actin filaments, which allows them to effectively regulate actin filament dynamics . They are present in micromolar concentrations in the cytoplasm, ensuring that most barbed ends are capped .
Expression Patterns and Tissue Distribution: CP is ubiquitously expressed in eukaryotic cells, with high concentrations at the leading edge of motile cells where actin polymerization is most active . Different isoforms of CP are expressed in a tissue-specific manner, with variations observed in muscle, neuronal, and other cell types .
Primary Biological Functions: The primary function of CP is to regulate the dynamics of actin filaments by capping their barbed ends, thus preventing the addition or loss of actin monomers . This regulation is crucial for various cellular processes, including cell motility, shape maintenance, and intracellular transport .
Role in Immune Responses and Pathogen Recognition: CP plays a role in immune responses by regulating the actin cytoskeleton, which is essential for the proper functioning of immune cells such as macrophages and neutrophils . It also contributes to the formation of structures like lamellipodia and filopodia, which are involved in pathogen recognition and phagocytosis .
Mechanisms with Other Molecules and Cells: CP interacts with various molecules to regulate actin filament dynamics. It binds to the barbed ends of actin filaments, blocking the addition and loss of actin subunits . CP activity is regulated by proteins such as V-1 and CARMIL, which inhibit its capping activity through steric and allosteric mechanisms .
Binding Partners and Downstream Signaling Cascades: CP interacts with proteins containing the capping protein interaction (CPI) motif, such as CARMIL, CD2AP, and the WASH complex subunit FAM21 . These interactions recruit CP to specific subcellular locations and modulate its actin-capping activity, influencing downstream signaling pathways involved in cell motility and membrane trafficking .
Regulatory Mechanisms Controlling Expression and Activity: CP expression and activity are regulated at multiple levels. Transcriptional regulation involves various transcription factors that control CP gene expression . Post-translational modifications, such as phosphorylation, also play a role in modulating CP activity .
Transcriptional Regulation and Post-Translational Modifications: CP activity is inhibited by phosphatidylinositol (4,5)-bisphosphate (PIP2), V-1, and CARMIL . These molecules bind to CP and prevent its interaction with actin filaments, thereby regulating actin filament dynamics .
Biomedical Research: CP is widely studied in biomedical research due to its crucial role in actin cytoskeleton regulation. It is used as a model to understand the mechanisms of actin filament dynamics and their implications in various diseases .
Diagnostic Tools and Therapeutic Strategies: CP and its regulators are potential targets for therapeutic interventions in diseases involving actin cytoskeleton dysregulation, such as cancer and neurodegenerative disorders . CP inhibitors and modulators are being explored as potential therapeutic agents .
Role Throughout the Life Cycle: CP plays a vital role throughout the life cycle of eukaryotic cells. During development, CP regulates cell shape and motility, which are essential for processes such as embryogenesis and tissue morphogenesis . In aging and disease, dysregulation of CP activity can lead to various pathologies, including cancer and neurodegenerative diseases .
