Integrins

Definition

Integrins are transmembrane receptors that facilitate cell-extracellular matrix (ECM) adhesion and play a crucial role in cell signaling. They are composed of alpha and beta subunits that allow cells to communicate with their surroundings, influencing processes such as cell migration, differentiation, and survival.

5 Must Know Facts For Your Next Test

1. Integrins exist in various forms, with each combination of alpha and beta subunits determining their specific binding properties to different ligands in the ECM.
2. The binding of integrins to ECM components triggers intracellular signaling pathways that influence cellular functions, such as proliferation and apoptosis.
3. Integrins play a significant role in embryogenesis, wound healing, and immune response by mediating cell migration and tissue organization.
4. Changes in integrin expression or function can lead to various diseases, including cancer metastasis, where altered adhesion properties allow tumor cells to invade other tissues.
5. Integrins can exist in active or inactive states; the conformational changes they undergo upon ligand binding are critical for their function in cell signaling and adhesion.

Review Questions

• How do integrins facilitate communication between cells and their extracellular environment?
  • Integrins bridge the gap between the cell's interior and the extracellular matrix by connecting the cytoskeleton to ECM proteins. This interaction not only provides mechanical stability but also activates signaling pathways that regulate essential processes like migration, differentiation, and survival. Through these signaling pathways, integrins help cells respond to changes in their environment, ensuring proper tissue function and homeostasis.
• Discuss the role of integrins in cell migration and how this process impacts tissue organization during development.
  • Integrins are crucial for cell migration as they mediate adhesion to the extracellular matrix, allowing cells to move efficiently. During development, integrins facilitate the organized movement of cells into specific locations where they form tissues and organs. This dynamic process involves the coordination of signaling events initiated by integrin binding, leading to cytoskeletal rearrangements that propel cells forward while maintaining connections with neighboring cells.
• Evaluate how alterations in integrin expression can contribute to disease progression, particularly in cancer metastasis.
  • Alterations in integrin expression can significantly affect cancer progression by enabling tumor cells to detach from primary tumors and invade surrounding tissues. Changes in integrin types or levels can enhance migratory capabilities and alter adhesive properties, facilitating metastasis. By promoting invasion into blood vessels or lymphatic systems, integrins allow cancer cells to spread to distant sites, making them critical targets for therapeutic interventions aimed at preventing metastasis.

Related terms

Extracellular Matrix (ECM): A complex network of proteins and carbohydrates surrounding cells, providing structural and biochemical support to the tissue.

Cell Adhesion Molecules (CAMs): Proteins located on the cell surface that mediate the adhesion between cells or between cells and the ECM.

Focal Adhesions: Large protein complexes through which cells adhere to the ECM, linking integrins to the actin cytoskeleton and facilitating signaling pathways.