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Identification of human cysteine‐rich secretory protein 3 (CRISP‐3) as a matrix protein in a subset of peroxidase‐negative granules of neutrophils and in the granules of eosinophils
Author(s) -
Udby Lene,
Calafat Jero,
Sørensen Ole E.,
Borregaard Niels,
Kjeldsen Lars
Publication year - 2002
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1189/jlb.72.3.462
Subject(s) - immunogold labelling , biology , granule (geology) , gelatinase , subcellular localization , cell fractionation , secretory protein , eosinophil peroxidase , percoll , biochemistry , cytochemistry , granulocyte , peroxidase , microbiology and biotechnology , enzyme , secretion , cytoplasm , immunology , antibody , in vitro , paleontology
Cysteine‐rich secretory protein 3 (CRISP‐3; also known as SGP28) was originally discovered in human neutrophilic granulocytes. We have recently developed a sensitive sandwich enzyme‐linked immunosorbent assay for CRISP‐3 and demonstrated the presence of CRISP‐3 in exocrine secretions. To investigate the subcellular localization and mobilization of CRISP‐3 in human neutrophils, we performed subcellular fractionation of resting and activated neutrophils on thee‐layer Percoll density gradients, release‐studies of granule proteins in response to different secretagogues, and double‐labeling immunogold electron microscopy. CRISP‐3 was found to be localized in a subset of granules with overlapping characteristics of specific and gelatinase granules and mobilized accordingly, thus confirming the hypothesis that peroxidase‐negative granules exist as a continuum from specific to gelatinase granules regarding protein content and mobilization. CRISP‐3 was found to be a matrix protein, which is stored in granules as glycosylated and as unglycosylated protein. The subcellular distribution of the two forms of CRISP‐3 was identical. In addition, CRISP‐3 was found as a granule protein in eosinophilic granulocytes. The presence of CRISP‐3 in peroxidase‐negative granules of neutrophils, in granules of eosinophils, and in exocrine secretions indicates a role in the innate host defense.