AI Article Synopsis
- The actin cytoskeleton is crucial for clathrin-mediated endocytosis (CME), but its specific functions are not fully understood due to limited structural data.
- Using advanced microscopy techniques, researchers discovered that actin forms a highly branched network at clathrin-coated structures (CCSs) in mouse cells, with various shapes based on the stage of endocytosis.
- The study suggests that the actin cytoskeleton primarily aids in constricting the bud neck and pushing internalized vesicles away from the plasma membrane, leading to a proposed model for the actin network's role in CME.
Article Abstract
Background: The dynamic actin cytoskeleton plays an important role in clathrin-mediated endocytosis (CME). However, its exact functions remain uncertain as a result of a lack of high-resolution structural information regarding actin architecture at endocytic sites.
Results: Using platinum replica electron microscopy in combination with electron tomography, we found that actin patches associated with clathrin-coated structures (CCSs) in cultured mouse cells consist of a densely branched actin network, in which actin filament barbed ends are oriented toward the CCS. The shape of the actin network varied from a small lateral patch at the periphery of shallow CCSs, to a collar-like arrangement around partly invaginated CCSs with actin filament barbed ends abutting the CCS neck, to a polarized comet tail in association with highly constricted or fully endocytosed CCSs.
Conclusions: Our data suggest that the primary role of the actin cytoskeleton in CME is to constrict and elongate the bud neck and drive the endocytosed vesicles from the plasma membrane. Moreover, in these processes, barbed ends directly push onto the load, as in a conventional propulsion mechanism. Based on our findings, we propose a model for initiation, evolution, and function of the dendritic actin network at CCSs.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3143238 | PMC |
| http://dx.doi.org/10.1016/j.cub.2011.05.048 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
The actin filament pointed-end depolymerase Srv2/CAP depolymerizes barbed ends, displaces capping protein, and promotes formin processivity.
Proc Natl Acad Sci U S A
February 2025
Departments of Physics, Cell Biology and Biochemistry, Emory University, Atlanta, GA 30322.
Cellular actin networks exhibit distinct assembly and disassembly dynamics, primarily driven by multicomponent reactions occurring at the two ends of actin filaments. While barbed ends are recognized as the hotspot for polymerization, depolymerization is predominantly associated with pointed ends. Consequently, mechanisms promoting barbed-end depolymerization have received relatively little attention.
View Article and Find Full Text PDFThe typical and the atypical filamins of Drosophila.
Genome
January 2025
Dalhousie University, Biology, Halifax, Nova Scotia, Canada;
The actin cytoskeleton is a dynamic mesh of filaments that provide structural support for cells and respond to external deformation forces. Active sensing of these forces is crucial for the function of the actin cytoskeleton, and some actin crosslinkers accomplish it. One such crosslinker is filamin, a highly conserved actin crosslinker dimeric protein with an elastic region capable of responding to mechanical changes in the actin cytoskeleton.
View Article and Find Full Text PDFTBC1D20 coordinates vesicle transport and actin remodeling to regulate ciliogenesis.
J Cell Biol
April 2025
Department of Genetics and Cell Biology, College of Life Sciences, State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China.
TBC1D20 deficiency causes Warburg Micro Syndrome in humans, characterized by multiple eye abnormalities, severe intellectual disability, and abnormal sexual development, but the molecular mechanisms remain unknown. Here, we identify TBC1D20 as a novel Rab11 GTPase-activating protein that coordinates vesicle transport and actin remodeling to regulate ciliogenesis. Depletion of TBC1D20 promotes Rab11 vesicle accumulation and actin deconstruction around the centrosome, facilitating the initiation of ciliogenesis even in cycling cells.
View Article and Find Full Text PDFLatrunculin U: a potent actin-disrupter from the Red Sea marine sponge .
Nat Prod Res
January 2025
Department of Pharmacology and Mays Cancer Center, University of Texas Health Science Center, San Antonio, Texas, USA.
During our efforts to identify biologically active compounds from Red Sea marine invertebrates, a new compound, latrunculin U (), was identified from the Red Sea sponge along with latrunculins A (), B (), and 16--latrunculin B (). The structures of the latrunculins were elucidated based on a combination of comprehensive 1D and 2D NMR analyses and high-resolution mass spectral determinations. The antiproliferative potency of each compound in HeLa cells was evaluated, and they had IC values ranging from 0.
View Article and Find Full Text PDFEffects of in vitro cytochalasin D and hypoxia on mitochondrial energetics and biogenesis, cell signal status and actin/tubulin/Hsp/MMP entity in air-breathing fish heart.
Comp Biochem Physiol C Toxicol Pharmacol
January 2025
Department of Zoology, University of Kerala, Kariavattom, Thiruvananthapuram 695581, Kerala, India; Inter-University Centre for Evolutionary and Integrative Biology-iCEIB, School of Life Sciences, University of Kerala, Kariavattom, Thiruvananthapuram 695 581, Kerala, India; Sastrajeevan Integrative Project, Centre for Integrative Stress and Ease-cRISE, Gregorian College of Advanced Studies, Sreekariyam, Thiruvananthapuram 695017, Kerala, India. Electronic address:
The cardiac actin cytoskeleton has a dynamic pattern of polymerisation. It is uncertain how far actin destabilisation impacts mitochondrial energetics and biogenesis, cell signal status, and structural entities in cardiomyocytes, particularly in hypoxic conditions. We thus tested the in vitro action of cytochalasin D (Cyt D), an inhibitor of actin polymerisation, in hypoxic ventricular explants to elucidate the role of the actin in mitochondrial energetics and biogenesis, cell signals and actin/tubulin/hsps/MMPs dynamics in hypoxic air-breathing fish hearts.
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!