title: PLUNC in human nasal lavage fluid: multiple isoforms that bind to lipopolysaccharide.
abstract: Here, we demonstrate the presence of multiple isoforms of palate lung nasal epithelial clone (PLUNC) in human nasal lavage fluid (NLF). Eight isoforms were separated by two-dimensional gel electrophoresis (2-DE), and peptide mapping of the proteins was performed using MALDI-TOF MS (matrix assisted laser desorption/ionization time of flight mass spectrometry) of tryptic and asparginase cleavages. The identification was verified by amino acid sequencing after analysis of collision-induced dissociation (CID) fragmentation spectra with nanoelectrospray MS/MS. One isoform showed an electrophoretic mobility shift after N-glycosidase treatment, indicating that at least one of the PLUNC isoforms is glycosylated. We also demonstrate that PLUNC in NLF binds to lipopolysaccharide (LPS) in vitro; indeed, out of all proteins present in NLF only the PLUNC isoforms were found to adsorb to an LPS-coated surface. These results show that PLUNC is expressed as multiple LPS-binding isoforms in human NLF. The possibility that PLUNC may play a role in the innate immune response of the upper airways is inferred.
authors.affiliation: Division of Occupational and Environmental Medicine, Department of Molecular and Clinical Medicine, Faculty of Health Sciences, Linköping University, S-581 85 Linköping, Sweden.
authors.forename: Bijar
authors.initials: B
authors.lastname: Ghafouri
authors.forename: Erik
authors.initials: E
authors.lastname: Kihlström
authors.forename: Christer
authors.initials: C
authors.lastname: Tagesson
authors.forename: Mats
authors.initials: M
authors.lastname: Lindahl
mesh_terms: D015180:Electrophoresis, Gel, Two-Dimensional; D024202:Electrophoretic Mobility Shift Assay; D006023:Glycoproteins / Q000032:analysis* / Q000378:metabolism; D006801:Humans; D016350:Leucine Zippers; D008070:Lipopolysaccharides / Q000378:metabolism*; D017817:Nasal Lavage Fluid / Q000737:chemistry*; D010449:Peptide Mapping; D010750:Phosphoproteins / Q000032:analysis* / Q000378:metabolism; D011485:Protein Binding; D020033:Protein Isoforms / Q000378:metabolism; D020545:Respiratory Mucosa / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: C485599:BPIFA1 protein, human; D006023:Glycoproteins; D008070:Lipopolysaccharides; D010750:Phosphoproteins; D020033:Protein Isoforms