title: Proteinase 3 and CD177 are expressed on the plasma membrane of the same subset of neutrophils.
abstract: Proteinase 3 (PR3) is found in granules of all neutrophils but also on the plasma membrane of a subset of neutrophils (mPR3). CD177, another neutrophil protein, also displays a bimodal surface expression. In this study, we have investigated the coexpression of these two molecules, as well as the effect of cell activation on their surface expression. We can show that CD177 is expressed on the same subset of neutrophils as mPR3. Experiments show that the expression of mPR3 and CD177 on the plasma membrane is increased or decreased in parallel during cell stimulation or spontaneous apoptosis. Furthermore, we observed a rapid internalization and recirculation of mPR3 and plasma membrane CD177, where all mPR3 is replaced within 30 min. Our findings suggest that the PR3 found on the plasma membrane has its origin in the same intracellular storage as CD177, i.e., secondary granules and secretory vesicles and not primary granules. PR3- and CD177-expressing neutrophils constitute a subpopulation of neutrophils with an unknown role in the innate immune system, which may play an important role in diseases such as Wegener's granulomatosis and polycythemia vera.
authors.affiliation: Department of Clinical Sciences, Clinical Sciences in Lund, Lund University, 221 84 Lund, Sweden.
authors.forename: Susanne
authors.initials: S
authors.lastname: Bauer
authors.forename: Mohamed
authors.initials: M
authors.lastname: Abdgawad
authors.forename: Lena
authors.initials: L
authors.lastname: Gunnarsson
authors.forename: Mårten
authors.initials: M
authors.lastname: Segelmark
authors.forename: Hans
authors.initials: H
authors.lastname: Tapper
authors.forename: Thomas
authors.initials: T
authors.lastname: Hellmark
mesh_terms: D002462:Cell Membrane / Q000276:immunology*; D058851:GPI-Linked Proteins; D006801:Humans; D007519:Isoantigens / Q000096:biosynthesis*; D008562:Membrane Glycoproteins / Q000096:biosynthesis*; D053146:Myeloblastin / Q000096:biosynthesis*; D009504:Neutrophils / Q000166:cytology / Q000276:immunology*; D011956:Receptors, Cell Surface / Q000096:biosynthesis*
chemical_list: C407242:CD177 protein, human; D058851:GPI-Linked Proteins; D007519:Isoantigens; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D053146:Myeloblastin