Cadherins

Definition

Cadherins are a class of type-1 transmembrane proteins that play a crucial role in cell adhesion, helping cells stick to one another to form tissues. They are important for maintaining the structural integrity of tissues and are involved in signaling pathways that affect cell behavior, such as proliferation, differentiation, and apoptosis.

5 Must Know Facts For Your Next Test

1. Cadherins are calcium-dependent glycoproteins, meaning their function relies on the presence of calcium ions, which help stabilize their structure.
2. There are multiple types of cadherins, including E-cadherin (epithelial), N-cadherin (neural), and P-cadherin (placental), each playing unique roles in different tissues.
3. Dysregulation of cadherin expression is often associated with cancer progression, as loss of cadherin-mediated adhesion can lead to increased cell migration and metastasis.
4. Cadherins not only mediate cell-cell adhesion but also participate in signaling pathways that influence cellular processes like gene expression and cell cycle regulation.
5. The ability of cadherins to form homophilic interactions (binding to the same type of cadherin on adjacent cells) is critical for establishing tissue architecture and organization.

Review Questions

• How do cadherins contribute to the structural integrity of tissues?
  • Cadherins contribute to the structural integrity of tissues by facilitating homophilic adhesion between adjacent cells. This adhesion forms adherens junctions, which connect the cytoskeletons of neighboring cells, providing mechanical strength and stability. By maintaining tight connections between cells, cadherins help tissues resist deformation and maintain their shape during various physiological processes.
• Discuss the role of calcium ions in the function of cadherins.
  • Calcium ions are essential for the proper function of cadherins, as they help stabilize the protein's structure and promote its adhesive properties. When calcium binds to specific sites on cadherins, it induces conformational changes that allow cadherin molecules on adjacent cells to interact effectively. This calcium dependency highlights how fluctuations in calcium levels can impact cell adhesion and subsequently influence tissue integrity and cellular behavior.
• Evaluate the implications of cadherin dysregulation in cancer progression.
  • Dysregulation of cadherins can have significant implications for cancer progression. Loss or downregulation of specific cadherins, such as E-cadherin in epithelial cancers, can lead to decreased cell-cell adhesion. This loss enables cancer cells to become more motile and invasive, facilitating metastasis to distant sites. Furthermore, altered cadherin expression can disrupt normal signaling pathways, promoting cellular proliferation and survival, which contributes to tumorigenesis.

Related terms

Integrins: Integrins are transmembrane receptors that facilitate cell-extracellular matrix adhesion, playing a key role in cell signaling and communication.

Adherens Junctions: Adherens junctions are specialized cell junctions formed by cadherin proteins that connect the cytoskeleton of one cell to another, providing mechanical stability to tissues.

Catenins: Catenins are cytoplasmic proteins that bind to cadherins and link them to the actin cytoskeleton, playing a vital role in the formation and maintenance of adherens junctions.