title: The Kluyveromyces lactis alpha1,6-mannosyltransferase KlOch1p is required for cell-wall organization and proper functioning of the secretory pathway.
abstract: Mutants of Kluyveromyces lactis denominated vga (vanadate glycosylation affected) bear various combinations of glycosylation and cell-wall defects. The vga3 mutation of K. lactis was mapped in the KlOCH1 gene, encoding the functional homologue of the Saccharomyces cerevisiaealpha1,6-mannosyltransferase. Quantitative analysis of cell-wall components indicated a noticeable increase of chitin and beta1,6-glucans and a severe decrease of mannoproteins in the mutant cells as compared with the wild-type counterparts. Fine-structure determination of the beta1,6-glucan polymer indicated that, in the vga3-1 strain, the beta1,6-glucans are shorter and have more branches than in the wild-type strain. This suggests that cell-wall remodelling changes take place in K. lactis in the presence of glycosylation defects. Moreover, the vga3 cells showed a significantly improved capability of secreting heterologous proteins. Such a capability, accompanied by the highly reduced N-glycosylation, may be of biotechnological interest, especially when hyper-glycosylation of recombinant products must be avoided.
authors.affiliation: Department of Developmental and Cell Biology, University La Sapienza, Rome, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Uccelletti
authors.forename: Francesca
authors.initials: F
authors.lastname: Farina
authors.forename: Silvia
authors.initials: S
authors.lastname: Rufini
authors.forename: Paula
authors.initials: P
authors.lastname: Magnelli
authors.forename: Claudia
authors.initials: C
authors.lastname: Abeijon
authors.forename: Claudio
authors.initials: C
authors.lastname: Palleschi
mesh_terms: D000595:Amino Acid Sequence; D002473:Cell Wall / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D002686:Chitin / Q000032:analysis; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D017353:Gene Deletion; D005816:Genetic Complementation Test; D006031:Glycosylation; D007716:Kluyveromyces / Q000201:enzymology* / Q000502:physiology; D008364:Mannosyltransferases / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D008562:Membrane Glycoproteins / Q000032:analysis; D008969:Molecular Sequence Data; D009154:Mutation; D021381:Protein Transport; D017386:Sequence Homology, Amino Acid; D047071:beta-Glucans / Q000032:analysis / Q000737:chemistry
chemical_list: D005656:Fungal Proteins; D008562:Membrane Glycoproteins; D047071:beta-Glucans; C025363:mannoproteins; D002686:Chitin; D008364:Mannosyltransferases; C058478:alpha 1,6-mannosyltransferase