Cadherins

Definition

Cadherins are a class of type-1 transmembrane proteins that play a crucial role in cell-cell adhesion, allowing cells to bind together in a tissue-specific manner. These proteins are essential for maintaining the structural integrity of tissues and are involved in various cellular processes, including signaling pathways and the formation of adherens junctions. Their interactions influence not only tissue architecture but also processes such as cell motility and cancer progression.

5 Must Know Facts For Your Next Test

1. Cadherins are divided into classical cadherins, which are primarily involved in epithelial tissues, and non-classical cadherins, which have various roles in different tissue types.
2. The binding of cadherins is calcium-dependent; without calcium ions, cadherin molecules cannot properly adhere to each other.
3. In addition to their structural role, cadherins are involved in signaling pathways that influence cell behavior, such as growth, differentiation, and apoptosis.
4. Alterations in cadherin expression or function are often associated with cancer progression and metastasis, as they can affect cell migration and invasion.
5. The disruption of cadherin-mediated adhesion can lead to diseases such as cancer, where the loss of epithelial characteristics allows for increased cell motility and invasiveness.

Review Questions

• How do cadherins contribute to the formation of adherens junctions and what is their significance in maintaining tissue structure?
  • Cadherins contribute to the formation of adherens junctions by providing strong adhesion between adjacent cells through their extracellular domains. This binding is critical for maintaining tissue integrity as it keeps cells organized and connected within their respective tissues. Additionally, cadherins interact with catenins, linking them to the actin cytoskeleton, which helps stabilize these junctions and facilitates communication between cells, ensuring proper tissue function.
• Discuss the role of cadherins in cellular signaling pathways and how they can influence cell behavior beyond adhesion.
  • Cadherins are not just structural components; they also play an active role in cellular signaling pathways. When cadherins bind to each other, they can trigger intracellular signals that influence processes like cell growth, differentiation, and apoptosis. This signaling is crucial for maintaining homeostasis within tissues. Disruption of these signals can lead to unregulated growth or loss of differentiation, which is often observed in cancer cells.
• Evaluate the implications of altered cadherin expression on cancer metastasis and how this knowledge could inform treatment strategies.
  • Altered cadherin expression significantly impacts cancer metastasis by affecting cell-cell adhesion and promoting epithelial-mesenchymal transition (EMT), where cancer cells become more mobile and invasive. Understanding how cadherin levels change during tumor progression can provide insights into potential treatment strategies that aim to restore normal adhesion properties or target the signaling pathways associated with cadherin function. By focusing on enhancing the adhesive properties of cancer cells or inhibiting EMT processes, therapies could potentially reduce metastasis and improve patient outcomes.

Related terms

Adherens Junctions: Cellular structures that provide strong adhesion between cells and are formed by cadherin proteins interacting with each other and with the actin cytoskeleton.

Catenins: A group of proteins that link cadherins to the actin cytoskeleton, playing a critical role in the stability and signaling of adherens junctions.

Epithelial-Mesenchymal Transition (EMT): A biological process in which epithelial cells lose their cell-cell adhesion properties, often involving cadherin downregulation, and gain migratory and invasive capabilities, which is crucial in development and cancer metastasis.