Regulation and Processing of a Precursor Form of Eosinophil Granule Major Basic Protein (ProMBP) in Differentiating Eosinophils
Open Access
- 15 July 1998
- journal article
- Published by American Society of Hematology in Blood
- Vol. 92 (2) , 623-631
- https://doi.org/10.1182/blood.v92.2.623
Abstract
The cDNA for eosinophil granule major basic protein (MBP) encodes a prepromolecule with a total length of 222 amino acids (preproMBP). PreproMBP includes a secretory leader of 15 amino acids, an acidic propiece of 90 amino acids, and a basic MBP portion of 117 amino acids. The function of the propiece, which has a predicted pI of 3.9, is unknown, but it gives proMBP an overall acidic charge. Because proMBP is not found in mature eosinophils, we analyzed eosinophil differentiation in interleukin-5 (IL-5)–stimulated umbilical cord stem cells cultured for 24 days. By immunofluorescence, proMBP appeared by day 6 and peaked on day 18, whereas MBP was prominent at days 12 to 24. By day 6, Western blots detected heterogeneous glycosylated 33-kD proMBP; its peak expression occurred on day 12. Western blots showed sequential processing of 33-kD proMBP to an 18-kD intermediate form and finally to 14-kD MBP. By dual label immunoelectron microscopy, proMBP was localized primarily to large uncondensed eosinophil granules, whereas MBP was localized to granules containing a condensed central area. Thus, proMBP is likely expressed and processed as the granule condenses in a multistep process to 14-kD MBP in differentiating eosinophils.Keywords
This publication has 33 references indexed in Scilit:
- Distinguishing features of basophil and neutrophil activation by major basic proteinJournal of Allergy and Clinical Immunology, 1994
- Biochemical properties, activities, and presence in biologic fluids of eosinophil granule major basic proteinJournal of Allergy and Clinical Immunology, 1994
- Induction of Normal Human Eosinophil Migration in vitro by Substance PActa Haematologica, 1993
- Ultrastructural localization of antigenic sites on osmium-fixed tissues applying the protein A-gold technique.Journal of Histochemistry & Cytochemistry, 1983
- Ultrastructural visualization of complex carbohydrates in eosinophilic leukocytesJournal of Anatomy, 1982
- IDENTIFICATION BY IMMUNOFLUORESCENCE OF EOSINOPHIL GRANULE MAJOR BASIC PROTEIN IN LUNG TISSUES OF PATIENTS WITH BRONCHIAL ASTHMAThe Lancet, 1982
- Elevated serum levels of the eosinophil granule major basic protein in patients with eosinophilia.Journal of Clinical Investigation, 1981
- Localization of the guinea pig eosinophil major basic protein to the core of the granuleThe Journal of cell biology, 1978
- Intracellular Aspects of the Process of Protein SynthesisScience, 1975
- An ultrastructural study of human eosinophil granules: Maturational stages and pyroantimonate reactive cationJournal of Anatomy, 1970