Actin Reorganization Antibody Sampler Kit

Background

Ubiquitous actin protein comprises the major structural component of the eukaryotic cytoskeleton. The formation and continual reorganization of the actin cytoskeleton is a key step in many biological processes, including cell motility, cytokinesis, endocytosis, embryonic development, tissue regeneration and the stress response (1). The small protein cofilin is one of a conserved family of actin-binding proteins that promote actin filament regeneration by severing preexisting filaments (2). Phosphorylation of cofilin at Ser3 by LIMK or TESK inhibits cofilin severing activity (3-5). Ezrin, radixin, and moesin (ERM) proteins function as linker proteins and signal transducers between the plasma membrane and actin cytoskeleton. These proteins are involved in cell adhesion, membrane ruffling, and microvilli formation (6,7). Interactive cytosolic ERM proteins exist as monomers or dimers that form both intra- and intermolecular associations through their amino- and carboxy-terminal domains (8). Phosphorylation at carboxy-terminal threonine residues (Thr567 of ezrin, radixin at Thr564 and Thr558 of moesin) may alter protein conformation and disrupt these protein associations and result in ERM protein activation (9,10). Vasodilator-stimulated phosphoprotein (VASP) is an adaptor protein that links the cytoskeleton with signal transduction pathways to act in fibroblast migration, platelet activation and axon guidance (11,12). Three phosphorylation sites (Ser157, Ser239, and Thr278) have been identified, with phosphorylation of Ser239 by PKG serving as a marker for nitric oxide and cGMP signaling (13). VASP Ser157 can act as a substrate for both PKA and PKC (14,15). Active VASP appears to promote actin polymerization by restricting actin filament capping, with PKA phosphorylation inhibiting this anti-capping activity (16).