key term - Cadherins

Definition

Cadherins are a class of type-1 transmembrane proteins that play essential roles in cell-cell adhesion, allowing cells to stick together to form tissues. They are critical for maintaining the structure and integrity of tissues by facilitating strong connections between adjacent cells through their extracellular domains, which interact with cadherins on neighboring cells. This adhesion is vital for various cellular activities, including signaling processes that regulate cell growth, differentiation, and migration.

5 Must Know Facts For Your Next Test

1. Cadherins are dependent on calcium ions (Ca2+) for their adhesive function, which helps stabilize their structure and promote binding between cells.
2. There are several types of cadherins, including E-cadherin (epithelial), N-cadherin (neuronal), and P-cadherin (placental), each serving specific functions in different tissues.
3. Cadherin expression can influence cellular behavior; for example, the loss of E-cadherin is associated with increased cell motility and cancer metastasis.
4. Cadherins not only facilitate cell adhesion but also participate in signaling pathways that regulate cellular processes like proliferation and apoptosis.
5. Mutations or abnormalities in cadherin function can lead to various diseases, including cancer, where disrupted adhesion contributes to tumor progression.

Review Questions

• How do cadherins contribute to the maintenance of tissue integrity?
  • Cadherins maintain tissue integrity by enabling strong adhesion between adjacent cells. They form homophilic interactions, meaning cadherins from one cell bind to identical cadherins on another cell. This connection not only helps hold cells together but also influences the overall architecture of tissues. By coordinating cell shape and tissue structure, cadherins play a critical role in maintaining functional tissues.
• Discuss the role of cadherins in cellular signaling and how this affects cellular activities.
  • Cadherins are involved in cellular signaling by connecting with intracellular proteins called catenins. This interaction links cadherins to the actin cytoskeleton and triggers signaling pathways that affect cell behavior. For instance, when cadherin bonds are formed, it can lead to changes in gene expression that regulate processes like cell proliferation and survival. Thus, cadherins not only facilitate adhesion but also serve as important signals for various cellular activities.
• Evaluate the implications of cadherin dysfunction in cancer progression and metastasis.
  • Dysfunction in cadherins can have significant implications for cancer progression and metastasis. For example, reduced expression or loss of E-cadherin is commonly observed in epithelial cancers, leading to weakened cell-cell adhesion. This loss allows cancerous cells to become more mobile and invasive, facilitating their spread beyond the primary tumor site. Understanding cadherin dysfunction helps researchers develop targeted therapies aimed at restoring normal adhesion mechanisms in cancer treatment.

Related terms

Cell Adhesion Molecules (CAMs): A group of proteins located on the cell surface involved in the binding of cells to each other and to the extracellular matrix.

Catenins: Proteins that bind to cadherins and connect them to the actin cytoskeleton, playing a role in maintaining the stability of cell-cell junctions.

Tight Junctions: Specialized connections between adjacent epithelial cells that create a barrier to prevent the passage of substances between them.