Calreticulin exposure

Definition

Calreticulin exposure refers to the process where calreticulin, a chaperone protein found in the endoplasmic reticulum, is translocated to the cell surface during immunogenic cell death. This exposure acts as an 'eat me' signal for phagocytic cells, facilitating the recognition and uptake of dying cells by the immune system, which is crucial for eliciting an adaptive immune response.

5 Must Know Facts For Your Next Test

1. Calreticulin exposure is considered a critical hallmark of immunogenic cell death, indicating that a cell is dying in a way that can trigger an immune response.
2. When calreticulin is exposed on the surface of dying cells, it promotes their recognition by dendritic cells, enhancing antigen presentation and stimulating T cell activation.
3. This process can be influenced by various treatments such as chemotherapy or certain types of radiation that induce immunogenic cell death.
4. Calreticulin's role as an 'eat me' signal is complemented by other factors like ATP release and HMGB1 (High Mobility Group Box 1) protein release from dying cells.
5. Understanding calreticulin exposure has significant implications for cancer therapies aimed at enhancing the effectiveness of immunotherapies by promoting anti-tumor immune responses.

Review Questions

• How does calreticulin exposure contribute to the process of immunogenic cell death and its impact on the immune response?
  • Calreticulin exposure is essential for signaling that a cell is undergoing immunogenic cell death. This process activates the immune response by marking dying cells with calreticulin on their surface, which serves as a signal for phagocytic cells to engulf them. The effective uptake of these cells enhances antigen presentation to T cells, leading to a robust adaptive immune response against potentially harmful agents such as tumors or pathogens.
• Discuss how calreticulin exposure interacts with other signals released during immunogenic cell death and why this synergy is important.
  • Calreticulin exposure works in synergy with other signals released during immunogenic cell death, such as ATP and HMGB1. These signals together create a more robust alert system for the immune system. ATP acts as a chemotactic agent attracting immune cells to the site of cell death, while HMGB1 functions as a potent DAMP that further activates various immune pathways. This combined signaling increases the chances of effective recognition and destruction of harmful cells.
• Evaluate the significance of calreticulin exposure in developing new cancer therapies that utilize immunogenic cell death.
  • Calreticulin exposure plays a pivotal role in the development of innovative cancer therapies that leverage immunogenic cell death. By understanding how calreticulin acts as an 'eat me' signal, researchers are focusing on strategies that can induce its exposure in tumor cells through different treatments like chemotherapy or radiotherapy. This not only enhances the visibility of tumor cells to the immune system but also potentially improves patient outcomes by increasing anti-tumor immunity and reducing tumor recurrence rates through effective activation of T cells and other immune mechanisms.

Related terms

Immunogenic cell death: A form of cell death that activates the immune system by exposing specific signals and releasing danger-associated molecular patterns (DAMPs), which can lead to an adaptive immune response.

Phagocytosis: The process by which certain cells, known as phagocytes, engulf and digest cellular debris, pathogens, and dying cells, playing a vital role in the immune response.

DAMPs (Damage-Associated Molecular Patterns): Molecules released by stressed or dying cells that alert the immune system to potential threats and contribute to the activation of immune responses.