title: Paramecium GPI proteins: variability of expression and localization.
abstract: In Paramecium primaurelia, the two major classes of cell surface proteins, the surface antigen (SAg) and the surface GPI proteins (SGPs), are linked to the plasma membrane through a glycosylphosphatidylinositol (GPI) anchor. In the present study, we have characterized the expression of the SGPs in several geographical strains of P. primaurelia and P. tetraurelia at different temperatures, 23 degrees C and 32 degrees C. The identification of the expressed SGPs was performed on purified cilia, by establishing the SGP SDS-PAGE profiles under four different conditions: with or without their anchoring lipid, cleaved with a Bacillus thuringiensis phosphatidylinositol-specific phospholipase C (PI-PLC), and either in a reduced or in an unreduced state. This screening revealed the existence of specific sets of ciliary SGPs, as a function of temperature and the geographical origin of the strains. The SGPs the most abundant at 23 degrees C and 32 degrees C displayed a rapid turnover. We also looked for the presence of PI-PLC releasable proteins in purified cortices. In addition to the SAg and SGPs, the cortical fraction was shown to contain other PI-PLC releasable proteins, not found in the ciliary fraction, thus localized exclusively in the interciliary region.
authors.affiliation: Centre de Génétique Moléculaire, Centre National de la Recherche Scientifique, associé à l'Université Pierre et Marie Curie, Gif-sur-Yvette, France. capdeville@cgm.cnrs-gif.fr
authors.forename: Y
authors.initials: Y
authors.lastname: Capdeville
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000096:biosynthesis / Q000302:isolation & purification; D000954:Antigens, Surface / Q000096:biosynthesis / Q000302:isolation & purification; D005591:Chemical Fractionation; D017261:Glycosylphosphatidylinositols / Q000378:metabolism*; D008565:Membrane Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D010247:Paramecium / Q000254:growth & development / Q000378:metabolism*; D015800:Protozoan Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D013696:Temperature
chemical_list: D000953:Antigens, Protozoan; D000954:Antigens, Surface; D017261:Glycosylphosphatidylinositols; D008565:Membrane Proteins; D015800:Protozoan Proteins