Related Experiment Video
Updated: Jan 1, 2026
05:50
Measuring Cell-Edge Protrusion Dynamics during Spreading using Live-Cell Microscopy
Published on: November 1, 2021
2.7K
Actin protrusions push at apical junctions to maintain E-cadherin adhesion.
John Xiao He Li1, Vivian W Tang1, William M Brieher2
1Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801.
Summary
Actin microspikes continuously push on cell junctions, maintaining epithelial cell adhesion. This protrusive activity prevents myosin II from disrupting cadherin bonds, ensuring cell sheet integrity.
Area of Science:
- Cell biology
- Biophysics
Background:
- Cadherin-mediated cell-cell adhesion is crucial for tissue integrity.
- The exact role of actin in maintaining established cell-cell adhesion is not fully understood.
Purpose of the Study:
- To investigate the role of actin protrusive activity in maintaining cell-cell adhesion in confluent epithelial sheets.
- To identify the molecular mechanisms underlying actin's role in cadherin adhesion.
Main Methods:
- Live cell imaging of Madin-Darby canine kidney (MDCK) cells.
- Electron microscopy.
- RNA interference (RNAi) to deplete actin assembly factors.
- Myosin II activity assays.
Main Results:
- Actin microspikes containing E-cadherin were observed at apical junctions of MDCK cells.
- Microspike activity correlated with the formation and maintenance of cadherin clusters.
- Depletion of Arp2/3, EVL, and CRMP-1 led to myosin II-dependent unzipping of cadherin bonds.
Conclusions:
- Actin polymerization-dependent protrusive activity is essential for maintaining cadherin-mediated cell-cell adhesion in epithelial sheets.
- This activity counteracts myosin II-dependent contractility, preventing the disruption of cell junctions.
- Arp2/3, EVL, and CRMP-1 are critical for the actin-based protrusive forces that stabilize cell adhesion.
Related Concept Videos
01:24Adherens Junctions
6.0K
Strong contact points between adjacent cells anchor them to each other, forming tissues. Such anchoring junctions are of two types – adherens junctions and desmosomes. Adherens junctions are abundant in tissues such as epithelium and endothelium, forming a continuous zone of adhesion called the adhesion belt. In other tissues, such as heart muscle, they appear as clusters, linking the cells to produce coordinated heart muscle contraction.
Adherens Junctions are Dynamic
Adherens Junctions are Dynamic
6.0K
01:26Tension Response at Adherens Junctions
3.4K
The adherens junctions that anchor cells together are multi-protein complexes that dynamically adapt to mechanical stimuli such as tensile forces and shear stress. Mechanosensory proteins in these junctions can sense such mechanical stimuli and undergo a shift in their conformation, resulting in an altered function — a process called mechanotransduction.
α-Catenin as a Mechanosensory Protein
The α-catenin of adherens junctions is an allosteric protein with three VH (vinculin...
α-Catenin as a Mechanosensory Protein
The α-catenin of adherens junctions is an allosteric protein with three VH (vinculin...
3.4K
01:31Mechanism of Lamellipodia Formation
3.5K
Cells migrating in response to external stimuli form lamellipodia, which are thin membrane protrusions supported by a mesh of linked, branched, or unbranched actin filaments. These actin filaments interact with myosin motor proteins, creating the dynamic actomyosin complex within the cytoskeleton. Contractility, or the ability to generate contractile stress, is inherent to the actomyosin complex. It helps cells detect the stiffness of the surrounding ECM and exert contractile force for...
3.5K
01:03Anchoring Junctions
4.7K
Anchoring junctions are multiprotein complexes that help cells connect to other cells and the extracellular matrix. Anchoring junctions are present on the lateral and basal surfaces of cells, providing strong and flexible connections. Focal adhesions are often formed due to cell interactions with the ECM substrata, which initiate signal transduction via kinase cascades and other mechanisms. Together, they provide stability and tissue integrity. There are three types of anchoring junctions:...
4.7K
01:13Actin Polymerization and Cell Motility
6.3K
Actin is a family of globular proteins that are highly abundant in eukaryotic cells. It makes up approximately 1-5% of total cell protein concentration. Actin monomers polymerize to form a complex network of polarized filaments, the actin cytoskeleton, that plays a crucial role in many cellular processes, including cell motility, division, endocytosis, and metastasis of cancer cells.
Actin cytoskeleton dynamics can produce pushing, pulling, and resistance forces that help the cell to migrate....
Actin cytoskeleton dynamics can produce pushing, pulling, and resistance forces that help the cell to migrate....
6.3K
01:39Mechanism of Filopodia Formation
3.0K
Filopodia are thin, actin-rich cellular protrusions that play an important role in many fundamental cellular functions. They vary in their occurrence, length, and positioning in different cell types, suggesting their diverse roles.
Their main function is to guide migrating cells during normal tissue morphogenesis or cancer metastasis by recognizing and making initial contacts with the extracellular matrix. However, they can also act as stationary cell anchors or help to establish communication...
Their main function is to guide migrating cells during normal tissue morphogenesis or cancer metastasis by recognizing and making initial contacts with the extracellular matrix. However, they can also act as stationary cell anchors or help to establish communication...
3.0K