CR3 ruffles FcγR's claim over phagocytic cups
1Geriatric Research Education and Clinical Center, Veterans Greater Los Angeles HealthCare System, Los Angeles, California, USA; Departments of Neurology and Medicine, University of California, Los Angeles, Los Angeles, California, USA.
The Journal of Biological Chemistry
|May 21, 2021
Summary
New imaging reveals complement receptor CR3-mediated phagocytosis occurs via sinking, while antibody-mediated phagocytosis uses cup formation. This challenges dogma, showing CR3
Area of Science:
- Immunology
- Cell Biology
Background:
- Phagocytosis is crucial for immunity and development, but its dynamic mechanisms and signaling pathways remain incompletely understood.
- Previous understanding relied on static images, limiting visualization of rapid phagocytic events.
Purpose of the Study:
- To visualize and elucidate the distinct mechanisms and interplay of different phagocytosis modes in real-time.
- To investigate the role of complement receptor CR3 in various phagocytic processes.
Main Methods:
- Utilized advanced time-lapse 3D imaging to capture the engulfment of erythrocytes by macrophages.
- Investigated phagocytosis mediated by complement receptor CR3 and antibody receptors.
Main Results:
- Confirmed complement receptor CR3-mediated phagocytosis occurs via a "sinking" mechanism.
- Demonstrated antibody-mediated phagocytosis proceeds through "cup formation."
- Showed phagocytic cup formation is not exclusive to antibody receptors and CR3 plays a complex regulatory role, with compensatory upregulation observed upon antibody-mediated phagocytosis inhibition.
Conclusions:
- Provides the first dynamic visualization of distinct phagocytosis mechanisms.
- Challenges established dogma regarding phagocytic cup formation and CR3 function.
- Reveals intricate interactions between different phagocytic pathways, advancing fundamental understanding of cellular engulfment.
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