Previous structures of Arp2/3 complex, determined in the absence of a nucleation-promoting factor and actin, reveal its inactive conformation. The study of the activated structure has been hampered by uncontrollable polymerization. We have engineered a stable activated complex consisting of Arp2/3 complex, the WCA activator region of N-WASP, and one actin monomer, and studied its structure in solution by small angle X-ray scattering (SAXS). The scattering data support a model in which the first actin subunit binds at the barbed end of Arp2, and disqualify an alternative model that places the first actin subunit at the barbed end of Arp3. This location of the first actin and bound W motif constrains the binding site of the C motif to subunits Arp2 and ARPC1, from where the A motif can reach subunits Arp3 and ARPC3. The results support a model of activation that is consistent with most of the biochemical observations.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2849165 | PMC |
| http://dx.doi.org/10.1016/j.str.2008.02.013 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
The WAVE complex in developmental and adulthood brain disorders.
Exp Mol Med
January 2025
Department of Neurosurgery, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, 08854, USA.
Actin polymerization and depolymerization are fundamental cellular processes required not only for the embryonic and postnatal development of the brain but also for the maintenance of neuronal plasticity and survival in the adult and aging brain. The orchestrated organization of actin filaments is controlled by various actin regulatory proteins. Wiskott‒Aldrich syndrome protein-family verprolin-homologous protein (WAVE) members are key activators of ARP2/3 complex-mediated actin polymerization.
View Article and Find Full Text PDFMitochondria- and ER-associated actin are required for mitochondrial fusion.
Nat Commun
January 2025
Groupe de Recherche en Signalisation Cellulaire and Département de Biologie Médicale, Université du Québec à Trois-Rivières, Trois-Rivières, QC, Canada.
Mitochondria are crucial for cellular metabolism and signalling. Mitochondrial activity is modulated by mitochondrial fission and fusion, which are required to properly balance metabolic functions, transfer material between mitochondria, and remove defective mitochondria. Mitochondrial fission occurs at mitochondria-endoplasmic reticulum (ER) contact sites, and requires the formation of actin filaments that drive mitochondrial constriction and the recruitment of the fission protein DRP1.
View Article and Find Full Text PDFFrom Molecules to Amoeboid Movement: A New Way for Understanding the Morphology Through Actin-Binding Proteins.
Biomolecules
December 2024
Zoological Institute RAS, St. Petersburg 199034, Russia.
Amoebozoa is a group of single-celled organisms that change their shape during locomotion. However, there is a taxon-specific complex of morphological characters inherent in the moving amoebae, known as locomotive forms. Actin is one of the proteins most important for amoeboid movement that, together with actin-binding proteins, construct the architecture of the cytoskeleton in the amoeboid cells.
View Article and Find Full Text PDFOverexpressed Palladin Rescues Enteropathogenic E. coli (EPEC) Pedestal Lengths in ArpC2 Depleted Cells.
Cytoskeleton (Hoboken)
December 2024
Department of Biological Sciences, Centre for Cell Biology, Development, and Disease, Simon Fraser University, Burnaby, British Columbia, Canada.
Enteropathogenic Escherichia coli (EPEC) causes diarrheal disease. Once ingested, these extracellular pathogens attach to the intestinal epithelial cells of their host, collapse the localized microvilli, and generate actin-rich structures within the host cells that are located beneath the attached bacteria, called "pedestals." Palladin is an actin-associated protein that cross-links and stabilizes actin filaments.
View Article and Find Full Text PDFActin-based deformations of the nucleus control mouse multiciliated ependymal cell differentiation.
Dev Cell
December 2024
Institut de biologie de l'Ecole normale supérieure (IBENS), Ecole normale supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France. Electronic address:
Ependymal cells (ECs) are multiciliated cells in the brain that contribute to cerebrospinal fluid flow. ECs are specified during embryonic stages but differentiate later in development. Their differentiation depends on genes such as GEMC1 and MCIDAS in conjunction with E2F4/5 as well as on cell-cycle-related factors.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!