Surface-bound myeloperoxidase is a ligand for recognition of late apoptotic neutrophils by human lung surfactant proteins A and D
Protein & Cell
;
(12): 563-572, 2010.
Article
in English
| WPRIM
| ID: wpr-757695
ABSTRACT
Surfactant proteins A (SP-A) and D (SP-D), both members of the collectin family, play a well established role in apoptotic cell recognition and clearance. Recent in vitro data show that SP-A and SP-D interact with apoptotic neutrophils in a distinct manner. SP-A and SP-D bind in a Ca(2+)-dependent manner to viable and early apoptotic neutrophils whereas the much greater interaction with late apoptotic neutrophils is Ca(2+)-independent. Cell surface molecules on the apoptotic target cells responsible for these interactions had not been identified and this study was done to find candidate target molecules. Myeloperoxidase (MPO), a specific intracellular defense molecule of neutrophils that becomes exposed on the outside of the cell upon apoptosis, was identified by affinity purification, mass-spectrometry and western blotting as a novel binding molecule for SP-A and SP-D. To confirm its role in recognition, it was shown that purified immobilised MPO binds SP-A and SP-D, and that MPO is surface-exposed on late apoptotic neutrophils. SP-A and SP-D inhibit binding of an anti-MPO monoclonal Ab to late apoptotic cells. Fluorescence microscopy confirmed that anti-MPO mAb and SP-A/SP-D colocalise on late apoptotic neutrophils. Desmoplakin was identified as a further potential ligand for SP-A, and neutrophil defensin as a target for both proteins.
Full text:
Available
Index:
WPRIM (Western Pacific)
Main subject:
Protein Binding
/
Binding, Competitive
/
Chemistry
/
Apoptosis
/
Peroxidase
/
Fluorescent Antibody Technique, Indirect
/
Cell Biology
/
Pulmonary Surfactant-Associated Protein A
/
Pulmonary Surfactant-Associated Protein D
/
Metabolism
Limits:
Humans
Language:
English
Journal:
Protein & Cell
Year:
2010
Type:
Article
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