The membrane-anchor of Paramecium temperature-specific surface antigens is a glycosylinositol phospholipid.
The temperature-specific G surface antigen of Paramecium primaurelia strain 156 was biosynthetically labeled by [3H]myristic acid in its membrane-bound form, but not in its soluble form. It could be cleaved by a phosphatidylinositol-specific phospholipase C from Trypanosoma brucei or from Bacillus cereus which released its soluble form with the unmasking of a particular glycosidic immunodeterminant called the crossreacting determinant. The Paramecium enzyme, capable of converting its membrane-bound form into the soluble one, was inhibited by a sulphydril reagent in the same way as the trypanosomal lipase. From this evidence we propose that the Paramecium temperature-specific surface antigens are anchored in the plasma membrane via a glycophospholipid, and that an endogenous phospholipase C may be involved in the antigenic variation process.
Capdeville
Y
Y
Centre de Génétique Moléculaire, Centre National de la Recherche Scientifique, Gif/Yvette, France.
Cardoso de Almeida
M L
ML
Deregnaucourt
C
C
D000215:Acylation; D000818:Animals; D000954:Antigens, Surface / Q000032:analysis*; D006017:Glycolipids / Q000378:metabolism*; D008563:Membrane Lipids / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D019814:Myristic Acid; D009227:Myristic Acids / Q000378:metabolism; D010247:Paramecium / Q000032:analysis / Q000276:immunology* / Q000378:metabolism; D010716:Phosphatidylinositols / Q000378:metabolism*; D013696:Temperature; D010738:Type C Phospholipases / Q000378:metabolism*
D000954:Antigens, Surface; D006017:Glycolipids; D008563:Membrane Lipids; D008565:Membrane Proteins; D009227:Myristic Acids; D010716:Phosphatidylinositols; D019814:Myristic Acid; D010738:Type C Phospholipases