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Calreticulin in the immune system: ins and outs

Malini Raghavan1, Sanjeeva J Wijeyesakere, Larry Robert Peters

  • 1Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109-5620, USA. malinir@umich.edu

Trends in Immunology
|September 11, 2012
PubMed

Insights

Calreticulin, a protein in the endoplasmic reticulum (ER), aids immune responses and antigen presentation. When on the cell surface, it enhances cancer cell uptake and tumor vaccine efficacy.

Area of Science:

  • Immunology
  • Cell Biology
  • Biochemistry

Background:

  • Calreticulin is a calcium-binding chaperone involved in protein folding within the endoplasmic reticulum (ER).
  • It plays a critical role in the assembly of major histocompatibility complex (MHC) class I molecules, influencing antigen presentation to cytotoxic T cells.
  • Calreticulin is typically ER-resident but can be found on the surface of cancer cells and dying cells.

Purpose of the Study:

  • To investigate the distinct functions of cell surface calreticulin.
  • To explore the role of extracellular calreticulin in cellular uptake and tumor vaccine models.

Main Methods:

  • The study likely involved cell-based assays to examine calreticulin localization and function.
  • Experiments may have utilized cancer cell models and tumor vaccine models to assess therapeutic potential.

Main Results:

  • Cell surface calreticulin promotes the phagocytic uptake of cancer cells.
  • Drugs that induce cell surface calreticulin expression enhance tumor protection in vaccine models, dependent on extracellular calreticulin.

Conclusions:

  • Cell surface calreticulin has critical roles beyond its ER functions, impacting immune surveillance and cancer therapy.
  • Further research into calreticulin's diverse functions is essential for advancing glycoprotein folding knowledge and developing novel cancer therapeutics.

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