Structural Insights into De Novo Actin Polymerization
Overview
Authors
Affiliations
Many cellular functions depend on rapid and localized actin polymerization/depolymerization. Yet, the de novo polymerization of actin in cells is kinetically unfavorable because of the instability of polymerization intermediates (small actin oligomers) and the actions of actin monomer binding proteins. Cells use filament nucleation and elongation factors to initiate and sustain polymerization. Structural biology is beginning to shed light on the diverse mechanisms by which these unrelated proteins initiate polymerization, undergo regulation, and mediate the transition of monomeric actin onto actin filaments. A prominent role is played by the W domain, which in some of these proteins occurs in tandem repeats that recruit multiple actin subunits. Pro-rich regions are also abundant and mediate the binding of profilin-actin complexes, which are the main source of polymerization competent actin in cells. Filament nucleation and elongation factors frequently interact with Rho-family GTPases, which relay signals from membrane receptors to regulate actin cytoskeleton remodeling.
Rajendran D, Vinayagam S, Sekar K, Bhowmick I, Sattu K Microb Ecol. 2024; 87(1):154.
PMID: 39681734 PMC: 11649735. DOI: 10.1007/s00248-024-02444-6.
Functional Mimicry of Eukaryotic Actin Assembly by Pathogen Effector Proteins.
Alqassim S Int J Mol Sci. 2022; 23(19).
PMID: 36232907 PMC: 9569871. DOI: 10.3390/ijms231911606.
Bonifacino T, Zerbo R, Balbi M, Torazza C, Frumento G, Fedele E Int J Mol Sci. 2021; 22(22).
PMID: 34830115 PMC: 8619465. DOI: 10.3390/ijms222212236.
Faria M, Domingues R, Bugalho M, Silva A, Matos P Cancers (Basel). 2021; 13(21).
PMID: 34771624 PMC: 8582450. DOI: 10.3390/cancers13215460.
Induced Arp2/3 Complex Depletion Increases FMNL2/3 Formin Expression and Filopodia Formation.
Dimchev V, Lahmann I, Koestler S, Kage F, Dimchev G, Steffen A Front Cell Dev Biol. 2021; 9:634708.
PMID: 33598464 PMC: 7882613. DOI: 10.3389/fcell.2021.634708.