Isolation and Partial Characterization of Pneumocin, a Novel Apical Membrane Surface Glycoprotein Marker of Rat Type II Cells
| Autor: | Jamson S. Lwebuga-Mukasa |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
Male
Pulmonary and Respiratory Medicine Glycosylation Blotting Western Clinical Biochemistry Neuraminidase Lamellar granule Peptide Mapping Chromatography Affinity Mice Agglutinin Glycolipid Affinity chromatography Sialoglycoprotein Lectins Animals Chymotrypsin Trypsin Microscopy Immunoelectron Lung Molecular Biology chemistry.chemical_classification Mice Inbred BALB C Membrane Glycoproteins biology Cell Membrane Antibodies Monoclonal Lectin Rats Inbred Strains Cell Biology Apical membrane Rats Molecular Weight Pulmonary Alveoli Biochemistry chemistry biology.protein Plant Lectins Glycoprotein |
| Zdroj: | American Journal of Respiratory Cell and Molecular Biology. 4:479-488 |
| ISSN: | 1535-4989 1044-1549 |
| DOI: | 10.1165/ajrcmb/4.6.479 |
| Popis: | Rat alveolar type II pneumocytes, in situ, label with Maclura pomifera agglutinin (MPA), a plant lectin that recognizes alpha-galactosyl oligosaccharide residues of glycoproteins and glycolipids. To study the glycoproteins recognized by the lectin, MPA lectin affinity chromatography was used to isolate a novel glycoprotein, pneumocin, from type II and whole rat lung cell membranes. Pneumocin isolated from adult rat lungs was a non-disulfide-linked sialoglycoprotein with an Mr of 165 kD. Asparagine-linked oligosaccharides contributed 5 to 10% to the Mr. Two-dimensional chymotryptic peptide maps of pneumocin isolated from whole lung membranes and type II cells were similar. The glycoprotein partitioned in the detergent phase on Triton X-114 phase separation. Murine monoclonal antibodies developed against the purified glycoprotein localized on apical membranes of type II pneumocytes in situ. The antibodies did not label type I cells or lamellar bodies but labeled luminal surfaces of vesicular structures of type II cells. Isolated type II cells labeled with antibodies after 1 d in culture but showed significantly less staining of cells after 4 d of culture. These observations demonstrate that pneumocin is a cell surface sialoglycoprotein marker of type II cells. Western blot analysis of liver and kidney cell membranes suggest that related glycoproteins may also be present in those tissues. The isolation technique and monoclonal antibodies should permit further characterization and functional studies of the glycoprotein. |
| Databáze: | OpenAIRE |
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