+ Site Statistics
References:
52,654,530
Abstracts:
29,560,856
PMIDs:
28,072,755
+ Search Articles
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ PDF Full Text
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Translate
+ Recently Requested

F-actin waves, actin cortex disassembly and focal exocytosis driven by actin-phosphoinositide positive feedback



F-actin waves, actin cortex disassembly and focal exocytosis driven by actin-phosphoinositide positive feedback



Cytoskeleton 73(4): 180-196



Actin polymerization is controlled by the phosphoinositide composition of the plasma membrane. However, the molecular mechanisms underlying the spatiotemporal regulation of actin network organization over extended length scales are still unclear. To observe phosphoinositide-dependent cytoskeletal dynamics we combined the model system of frustrated phagocytosis, total internal reflection microscopy and manipulation of the buffer tonicity. We found that macrophages interacting with IgG-coated glass substrates formed circular F-actin waves on their ventral surface enclosing a region of plasma membrane devoid of cortical actin. Plasma membrane free of actin cortex was strongly depleted of PI(4,5)P2 , but enriched in PI(3,4)P2 and displayed a fivefold increase in exocytosis. Wave formation could be promoted by application of a hypotonic shock. The actin waves were characteristic of a bistable wavefront at the boundary between the regions of membrane containing and lacking cortical actin. Phosphoinositide modifiers and RhoGTPase activities dramatically redistributed with respect to the wavefronts, which often exhibited spatial oscillations. Perturbation of either lipid or actin cytoskeleton-related pathways led to rapid loss of both the polarized lipid distribution and the wavefront. As waves travelled over the plasma membrane, wavefront actin was seen to rapidly polymerize and depolymerize at pre-existing clusters of FcγRIIA, coincident with rapid changes in lipid composition. Thus the potential of receptors to support rapid F-actin polymerization appears to depend acutely on the local concentrations of multiple lipid species. We propose that interdependence through positive feedback from the cytoskeleton to lipid modifiers leads to coordinated local cortex remodeling, focal exocytosis, and organizes extended actin networks.

(PDF emailed within 0-6 h: $19.90)

Accession: 057851840

Download citation: RISBibTeXText

PMID: 26915738

DOI: 10.1002/cm.21287


Related references

Histamine-Evoked Chromaffin Cell Scinderin Redistribution, F-Actin Disassembly, and Secretion: In the Absence of Cortical F-Actin Disassembly, an Increase in Intracellular Ca-2+ Fails to Trigger Exocytosis. Journal of Neurochemistry 65(3): 1297-1308, 1995

Enhancement of actin-depolymerizing factor/cofilin-dependent actin disassembly by actin-interacting protein 1 is required for organized actin filament assembly in the Caenorhabditis elegans body wall muscle. Molecular Biology of the Cell 17(5): 2190-2199, 2006

Actin Migration Driven by Directional Assembly and Disassembly of Membrane-Anchored Actin Filaments. Cell Reports 12(4): 648-660, 2016

Tropomyosin binding to F-actin protects the F-actin from disassembly by brain actin-depolymerizing factor (ADF). Cell Motility 2(1): 1-8, 1982

UNC-78, a C elegans homolog of actin-interacting protein 1, induces disassembly of actin filaments depending on stable association of ADF/Cofilin with F-actin. Molecular Biology of the Cell 12(Supplement): 285a, 2001

Actin-interacting Protein 1 Promotes Disassembly of Actin-depolymerizing Factor/Cofilin-bound Actin Filaments in a pH-dependent Manner. Journal of Biological Chemistry 291(10): 5146-5156, 2016

Identification of functional residues on Caenorhabditis elegans actin-interacting protein 1 (UNC-78) for disassembly of actin depolymerizing factor/cofilin-bound actin filaments. Journal of Biological Chemistry 279(30): 31697-31707, 2004

Assembly-disassembly of actin bundles in starfish oocytes: an analysis of actin-associated proteins in the isolated cortex. Developmental Biology 101(2): 263-273, 1984

Fluorescence probing of yeast actin subdomain 3/4 hydrophobic loop 262-274. Actin-actin and actin-myosin interactions in actin filaments. Journal of Biological Chemistry 272(27): 16829-16837, 1997

Changes in actin network during calcium-induced exocytosis in permeabilized GH3 cells: calcium directly regulates F-actin disassembly. Journal of Endocrinology 166(3): 677-687, 2000

Actin filament elongation from actin and profilin-actin; weakening of actin-bound ATP by profilin binding to actin equalizes the free energy changes. Biophysical Journal 82(1 Part 2): 381a, 2002

FT-Raman studies on the transformation of G-actin to F-actin, the binding of cisplatin and transplatin to F-actin and the effects of the conformation of F-actin. International Journal Of Biological Macromolecules. 20(2): 107-113, 1997

FHL3 is an Actin-binding Protein That Regulates a-Actinin-mediated Actin Bundling. FHL3 Localizes to Actin Stress Fibers and Enhances Cell Spreading and Stress Fiber Disassembly. The Journal of Biological Chemistry 278(26): 139-52, 2003

Crystalline actin tubes 1. is the conformation of the lanthanide induced actin tube monomer more like f actin than g actin. Biochimica et Biophysica Acta 624(1): 163-173, 1980

FHL3 is an actin-binding protein that regulates alpha-actinin-mediated actin bundling: FHL3 localizes to actin stress fibers and enhances cell spreading and stress fiber disassembly. Journal of Biological Chemistry 278(26): 24139-24152, 2003