We have examined the association of two cytoskeleton proteins, gelsolin and actin, with phosphatidylinositide-specific phospholipase Cgamma1 (PLCgamma1) in resting and thrombin-stimulated human platelets. In unstimulated platelets, gelsolin, actin and PLCgamma1 were immunoprecipitated as a complex by a polyclonal antibody to PLCgamma1. The association of gelsolin and actin was specific for PLCg...

Higher plants contain families of actin-encoding genes that are divergent and differentially expressed. Progress in understanding the functions and evolution of plant actins has been hindered by the large size of the actin gene families. In this study, we characterized the structure and evolution of the actin gene family in Arabidopsis thaliana. DNA blot analyses with gene-specific probes sugge...

It is proposed that force generation in muscle contraction occurs through a transition from a weakly bound state to a strongly bound state of myosin on actin during the ATPase reaction cycle. The chapters in this book probe the structural details of these interactions, with particular attention to the specific sites of interaction on each protein, the structural and dynamics properties of the b...

The localization of specific mRNAs and polyribo-somes within growth cones may permit a direct response to external signals and rapidly influence cy-cones was regulated by both age in culture and calcium (Crino and Eberwine, 1997). ␤-actin mRNAs localized Bronx, New York 10461 rapidly to growth cones in response to NT-3, a response which required microtubules and cAMP-dependent protein kinase A ...

Actin and actin-binding proteins are incorporated into HIV-1 particles, and F-actin has been suggested to bind the NC domain in HIV-1 Gag. Furthermore, F-actin has been frequently observed in the vicinity of HIV-1 budding sites by cryo-electron tomography (cET). Filamentous structures emanating from viral buds and suggested to correspond to actin filaments have been observed by atomic force mic...

During the spreading of a population of rat embryo cells, approximately 40% of the cells develop a strikingly regular network which precedes the formation of the straight actin filament bundles seen in the fully spread out cells. Immunofluorescence studies with antibodies specific for the skeletal muscle structural proteins actin, alpha-actinin, and tropomyosin indicate that this network is com...

The actin cytoskeleton is involved in key neuronal functions such as synaptic transmission and morphogenesis. However, the roles and regulation of actin cytoskeleton in memory formation remain to be clarified. In this study, we unveil the mechanism whereby actin cytoskeleton is regulated to form memory by exploring the roles of the major actin-regulatory proteins Arp2/3, VASP, and formins in lo...

Double labelling and the isolation of peptides specific to muscle actin were used to determine the amount of actin in young and senescent fibroblasts from chicken embryo. A 20-residue peptide produced from the C-terminus of muscle actin was found in amounts that indicated 6.9% of the protein of young fibroblasts and 11.5% of the protein of senescent fibroblasts to be actin. Two other peptides o...

The current study focuses on the molecular mechanisms responsible for actin assembly on a defined membrane surface: the phagosome. Mature phagosomes were surrounded by filamentous actin in vivo in two different cell types. Fluorescence microscopy was used to study in vitro actin nucleation/polymerization (assembly) on the surface of phagosomes isolated from J774 mouse macrophages. In order to p...

We propose a model solely based on actin treadmilling and polymerization which describes many characteristic states of actin-wave formation: spots, spirals, and traveling waves. In our model, as in experiments on cells recovering motility following actin depolymerization, we choose an isotropic low-density initial condition; polymerization of actin filaments then raises the density towards the ...