title: Identification of beta-1,6-glucosylated cell wall proteins in yeast and hyphal forms of Candida albicans.
abstract: Several cell wall proteins released from yeast and hyphal cells of Candida albicans by laminarinase reacted with an affinity-purified antiserum raised against beta-1,6-glucan. Binding of the antiserum was competitively inhibited by beta-1,6-glucan, but not by beta-1,3-glucan or isolated N-chains. Immunodetection was completely abolished when the proteins were treated with periodate. These results demonstrate that the laminarinase-released wall proteins of C. albicans possess an epitope consisting of beta-1,6-linked glucose residues. The yeast form of C. albicans contained four beta-1,6-glucosylated wall proteins, an Endo H-resistant protein of 125 kDa and three glycoproteins which became only detectable after Endo H digestion and had a molecular mass of 320, 170 and 44 kDa, respectively. As for the hyphal form, a different set of beta-1,6-glucosylated wall proteins was found consisting of two Endo H-resistant glycoproteins of 125 and 80 kDa, respectively, and two glycoproteins that after Endo H digestion had a molecular mass of 320 and 38 kDa, respectively. Sodium dodecyl sulfate-extractable wall proteins and medium proteins did not react with the beta-1,6-glucan antiserum. The beta-1,6-glucan epitope could be removed by aqueous hydrofluoric acid indicating that the epitope is phosphodiester-linked to the cell wall proteins. It is speculated that the epitope forms part of a GPI-anchor and might be involved in the anchoring of mannoproteins into the cell wall.
authors.affiliation: Institute of Molecular Cell Biology, University of Amsterdam, The Netherlands.
authors.forename: J C
authors.initials: JC
authors.lastname: Kapteyn
authors.forename: R C
authors.initials: RC
authors.lastname: Montijn
authors.forename: G J
authors.initials: GJ
authors.lastname: Dijkgraaf
authors.forename: F M
authors.initials: FM
authors.lastname: Klis
mesh_terms: D002176:Candida albicans / Q000737:chemistry* / Q000648:ultrastructure; D002473:Cell Wall / Q000737:chemistry; D000939:Epitopes / Q000032:analysis; D005656:Fungal Proteins / Q000032:analysis*; D005936:Glucans / Q000378:metabolism*; D006031:Glycosylation; D008562:Membrane Glycoproteins / Q000032:analysis*; D047071:beta-Glucans
chemical_list: D000939:Epitopes; D005656:Fungal Proteins; D005936:Glucans; D008562:Membrane Glycoproteins; D047071:beta-Glucans; C025363:mannoproteins; C064197:beta-1,6-glucan