Adherens Junctions

Definition

Adherens junctions are a type of cell-cell adhesion complex that mechanically connect the actin cytoskeletons of adjacent epithelial cells, providing structural integrity and facilitating communication between cells.

5 Must Know Facts For Your Next Test

1. Adherens junctions connect the actin cytoskeletons of adjacent epithelial cells, forming a continuous network that maintains tissue integrity and organization.
2. The cadherin family of transmembrane proteins are the primary components of adherens junctions, mediating cell-cell adhesion.
3. Adherens junctions play a crucial role in the establishment and maintenance of epithelial cell polarity, which is essential for proper tissue function.
4. The intracellular domain of cadherins interacts with catenin proteins, which link the cadherin complex to the actin cytoskeleton, strengthening the cell-cell adhesion.
5. Disruption of adherens junctions can lead to the loss of epithelial cell-cell adhesion, contributing to the development of various pathological conditions, such as cancer metastasis.

Review Questions

• Explain the role of adherens junctions in maintaining the structural integrity of epithelial tissues.
  • Adherens junctions are essential for maintaining the structural integrity of epithelial tissues by mechanically connecting the actin cytoskeletons of adjacent epithelial cells. This continuous network of cell-cell adhesions provides the necessary structural support to keep the cells organized and prevent them from separating, which is crucial for the proper function of epithelial tissues. The cadherin-catenin complexes within the adherens junctions anchor the actin cytoskeleton, creating a strong and cohesive cellular framework that preserves the overall tissue architecture.
• Describe the relationship between adherens junctions and epithelial cell polarity.
  • Adherens junctions play a critical role in the establishment and maintenance of epithelial cell polarity, which is essential for the proper function of epithelial tissues. The cadherin-catenin complexes within the adherens junctions help define the apical and basolateral domains of epithelial cells, ensuring that the cells maintain their distinct structural and functional characteristics. This polarized organization is crucial for processes such as selective transport, secretion, and absorption, which are vital for the physiological roles of epithelial tissues. The disruption of adherens junctions can lead to the loss of epithelial cell polarity, contributing to various pathological conditions.
• Analyze the potential consequences of disrupting adherens junctions in epithelial tissues, particularly in the context of disease development.
  • The disruption of adherens junctions can have severe consequences for the structural integrity and function of epithelial tissues. When the mechanical connections between the actin cytoskeletons of adjacent epithelial cells are compromised, the cells may become separated, leading to the loss of tissue organization and cohesion. This can contribute to the development of various pathological conditions, such as cancer metastasis, where the breakdown of cell-cell adhesions allows cancer cells to detach from the primary tumor and invade surrounding tissues. Additionally, the disruption of adherens junctions can impact epithelial cell polarity, which is crucial for the proper functioning of epithelial barriers and transport processes. The loss of epithelial cell polarity can further exacerbate disease progression and contribute to the development of other pathological conditions, highlighting the critical importance of adherens junctions in maintaining the structural and functional integrity of epithelial tissues.

Related terms

Tight Junctions: Tight junctions are a type of cell-cell adhesion complex that create a selectively permeable barrier between epithelial cells, controlling the movement of molecules and ions across the epithelium.

Desmosomes: Desmosomes are a type of cell-cell adhesion complex that anchor the intermediate filaments of adjacent cells, providing strong mechanical attachments between cells.

Actin Cytoskeleton: The actin cytoskeleton is a network of filamentous actin proteins that provide structural support and facilitate various cellular processes, including cell adhesion and motility.