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Plasma membrane alterations during apoptosis: role in corpse clearance.
1Division of Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden. bengt.fadeel@imm.ki.se
Antioxidants & Redox Signaling
|March 18, 2004
Summary
Apoptosis involves cellular self-destruction and clearance by macrophages. Key "eat me" signals like phosphatidylserine (PS) and "seek me" signals like lysophosphatidylcholine ensure efficient removal, preventing inflammation.
Area of Science:
- Cell Biology
- Immunology
Background:
- Apoptosis is programmed cell death crucial for tissue homeostasis.
- Efficient clearance of apoptotic cells by phagocytes prevents inflammation.
Purpose of the Study:
- To elucidate the molecular mechanisms and signals mediating apoptotic cell clearance.
- To understand how "eat me" and "seek me" signals facilitate phagocytosis.
Main Methods:
- Characterization of plasma membrane alterations during apoptosis.
- Identification of specific molecular signals exposed on apoptotic cells.
- Analysis of chemoattractant factors secreted by apoptotic cells.
Main Results:
- Phosphatidylserine (PS) and its oxidized form (PS-OX) act as "eat me" signals.
- Annexin I binds to PS, mediating engulfment by phagocytes.
- Plasma membrane blebbing concentrates PS on protrusions, enhancing recognition.
- Lysophosphatidylcholine serves as a "seek me" signal, recruiting phagocytes.
Conclusions:
- Apoptotic cells utilize specific molecular signals and structural changes for efficient clearance.
- This process prevents necrotic disintegration, inflammation, and tissue scarring.