scholarly journals The Role of Glucosidase I (Cwh41p) in the Biosynthesis of Cell Wall β-1,6-Glucan Is Indirect

1998 ◽  
Vol 9 (10) ◽  
pp. 2729-2738 ◽  
Author(s):  
Claudia Abeijon ◽  
Ling Yun Chen
Keyword(s):  
Cell Wall ◽  
Double Mutant ◽  
Biosynthetic Pathway ◽  
Slow Growth ◽  
Wild Type ◽  
Glucose Residue ◽  
Calcofluor White ◽  
Cell Wall Assembly ◽  
Wall Assembly

CWH41, a gene involved in the assembly of cell wall β-1,6-glucan, has recently been shown to be the structural gene forSaccharomyces cerevisiae glucosidase I that is responsible for initiating the trimming of terminal α-1,2-glucose residue in the N-glycan processing pathway. To distinguish between a direct or indirect role of Cwh41p in the biosynthesis of β-1,6-glucan, we constructed a double mutant, alg5Δ(lacking dolichol-P-glucose synthase) cwh41Δ, and found that it has the same phenotype as the alg5Δsingle mutant. It contains wild-type levels of cell wall β-1,6-glucan, shows moderate underglycosylation of N-linked glycoproteins, and grows at concentrations of Calcofluor White (which interferes with cell wall assembly) that are lethal tocwh41Δ single mutant. The strong genetic interactions of CWH41 with KRE6 andKRE1, two other genes involved in the β-1,6-glucan biosynthetic pathway, disappear in the absence of dolichol-P-glucose synthase (alg5Δ). The triple mutantalg5Δcwh41Δkre6Δ is viable, whereas the double mutant cwh41Δkre6Δ in the same genetic background is not. The severe slow growth phenotype and 75% reduction in cell wall β-1,6-glucan, characteristic of the cwh41Δkre1Δdouble mutant, are not observed in the triple mutantalg5Δcwh41Δkre1Δ. Kre6p, a putative Golgi glucan synthase, is unstable in cwh41Δ strains, and its overexpression renders these cells Calcofluor White resistant. These results demonstrate that the role of glucosidase I (Cwh41p) in the biosynthesis of cell wall β-1,6-glucan is indirect and that dolichol-P-glucose is not an intermediate in this pathway.

The role of the exocytic pathway in cell wall assembly in yeast

Yeast ◽  
2021 ◽  
Author(s):  
Qingguo Guo ◽  
Na Meng ◽  
Guanzhi Fan ◽  
Dong Sun ◽  
Yuan Meng ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Wall Assembly ◽  
Wall Assembly ◽  
Exocytic Pathway

scholarly journals Assemblies of DivIVA Mark Sites for Hyphal Branching and Can Establish New Zones of Cell Wall Growth in Streptomyces coelicolor

2008 ◽  
Vol 190 (22) ◽  
pp. 7579-7583 ◽  
Author(s):  
Antje Marie Hempel ◽  
Sheng-bing Wang ◽  
Michal Letek ◽  
José A. Gil ◽  
Klas Flärdh
Keyword(s):  
Cell Wall ◽  
Streptomyces Coelicolor ◽  
Time Lapse ◽  
Cell Wall Assembly ◽  
Peptidoglycan Synthesis ◽  
Wall Growth ◽  
Lateral Branches ◽  
Wall Assembly ◽  
Time Lapse Imaging

ABSTRACT Time-lapse imaging of Streptomyces hyphae revealed foci of the essential protein DivIVA at sites where lateral branches will emerge. Overexpression experiments showed that DivIVA foci can trigger establishment of new zones of cell wall assembly, suggesting a key role of DivIVA in directing peptidoglycan synthesis and cell shape in Streptomyces.

scholarly journals Polyglycylation of Tubulin Is Essential and Affects Cell Motility and Division in Tetrahymena thermophila

2000 ◽  
Vol 149 (5) ◽  
pp. 1097-1106 ◽  
Author(s):  
Lu Xia ◽  
Bing Hai ◽  
Yan Gao ◽  
Dylan Burnette ◽  
Rupal Thazhath ◽  
...  
Keyword(s):  
Double Mutant ◽  
Tetrahymena Thermophila ◽  
Slow Growth ◽  
Immunochemical Analysis ◽  
Wild Type ◽  
Specific Antibodies ◽  
Essential Function ◽  
Β Tubulin

We analyzed the role of tubulin polyglycylation in Tetrahymena thermophila using in vivo mutagenesis and immunochemical analysis with modification-specific antibodies. Three and five polyglycylation sites were identified at glutamic acids near the COOH termini of α- and β-tubulin, respectively. Mutants lacking all polyglycylation sites on α-tubulin have normal phenotype, whereas similar sites on β-tubulin are essential. A viable mutant with three mutated sites in β-tubulin showed reduced tubulin glycylation, slow growth and motility, and defects in cytokinesis. Cells in which all five polyglycylation sites on β-tubulin were mutated were viable if they were cotransformed with an α-tubulin gene whose COOH terminus was replaced by the wild-type COOH terminus of β-tubulin. In this double mutant, β-tubulin lacked detectable polyglycylation, while the α-β tubulin chimera was hyperglycylated compared with α-tubulin in wild-type cells. Thus, the essential function of polyglycylation of the COOH terminus of β-tubulin can be transferred to α-tubulin, indicating it is the total amount of polyglycylation on both α- and β-tubulin that is essential for survival.

scholarly journals Sophisticated Functions for a Simple Molecule: The Role of Glucosylceramides in Fungal Cells

2008 ◽  
Vol 2 ◽  
pp. LPI.S1014 ◽  
Author(s):  
Leonardo Nimrichter ◽  
Marcio L. Rodrigues ◽  
Eliana Barreto-Bergter ◽  
Luiz R. Travassos
Keyword(s):  
Cell Wall ◽  
Immune System ◽  
Building Block ◽  
Mammalian Cells ◽  
Recent Literature ◽  
Antifungal Drugs ◽  
Cell Wall Assembly ◽  
Wall Assembly ◽  
Ceramide Moiety

It is well known that mammalian glycosphingolipids (GSL) play key roles in different physiological and pathophysiological processes. The simplest GSL, glucosylceramide (GlcCer), is formed through the enzymatic transfer of glucose to a ceramide moiety. In mammalian cells this molecule is the building block for the synthesis of lactosylceramides and many other complex GSLs. In fungal cells GlcCer is a major neutral GSL that has been considered during decades merely as a structural component of cell membranes. The recent literature, however, describes the participation of fungal GlcCer in vital processes such as secretion, cell wall assembly, recognition by the immune system and regulation of virulence. In this review we discuss the most recent information regarding fungal GlcCer, including (i) new aspects of GlcCer metabolism, (ii) the involvement of these molecules in virulence mechanisms, (iii) their role as targets of new antifungal drugs and immunotherapeutic agents and, finally, (v) their potential participation on cellular signaling in response to different stimuli.

Secondary cell-wall assembly in flax phloem fibres: role of galactans

Planta ◽  
2005 ◽  
Vol 223 (2) ◽  
pp. 149-158 ◽  
Author(s):  
Tatyana Gorshkova ◽  
Claudine Morvan
Keyword(s):  
Cell Wall ◽  
Secondary Cell Wall ◽  
Cell Wall Assembly ◽  
Wall Assembly

Dissecting the role of dolichol in cell wall assembly in the yeast mutants impaired in early glycosylation reactions

Yeast ◽  
2007 ◽  
Vol 24 (4) ◽  
pp. 239-252 ◽  
Author(s):  
Jacek Orłowski ◽  
Katarzyna Machula ◽  
Anna Janik ◽  
Ewa Zdebska ◽  
Grazyna Palamarczyk
Keyword(s):  
Cell Wall ◽  
Cell Wall Assembly ◽  
Wall Assembly ◽  
Yeast Mutants

scholarly journals Bgs3p, a Putative 1,3-β-Glucan Synthase Subunit, Is Required for Cell Wall Assembly in Schizosaccharomyces pombe

2003 ◽  
Vol 2 (1) ◽  
pp. 159-169 ◽  
Author(s):  
Victoria Martín ◽  
Blanca García ◽  
Elena Carnero ◽  
Angel Durán ◽  
Yolanda Sánchez
Keyword(s):  
Cell Wall ◽  
Fission Yeast ◽  
Green Fluorescence Protein ◽  
Cell Wall Biosynthesis ◽  
Calcofluor White ◽  
Fungal Cell ◽  
Glucan Synthase ◽  
Cell Wall Assembly ◽  
Main Components ◽  
Wall Assembly

ABSTRACT β-Glucans are the main components of the fungal cell wall. Fission yeast possesses a family of β-glucan synthase-related genes. We describe here the cloning and characterization of bgs3 +, a new member of this family. bgs3 + was cloned as a suppressor of a mutant hypersensitive to Echinocandin and Calcofluor White, drugs that interfere with cell wall biosynthesis. Disruption of the gene is lethal, and a decrease in Bgs3p levels leads to rounded cells with thicker walls, slightly reduces the amount of the β-glucan, and raises the amount of α-glucan polymer. These cells finally died. bgs3 + is expressed in vegetative cells grown in different conditions and during mating and germination and is not enhanced by stress situations. Consistent with the observed expression pattern, Bgs3-green fluorescence protein (GFP-Bgs3p) was found at the growing tips during interphase and at the septum prior to cytokinesis, always localized to growth areas. We also found GFP-Bgs3p in mating projections, during the early stages of zygote formation, and at the growing pole during ascospore germination. We conclude that Bgs3p localization is restricted to growth areas and that Bgs3p is a glucan synthase homologue required for cell wall biosynthesis and cell elongation in the fission yeast life cycle.

scholarly journals NMR and LC-MS-Based Metabolomics to Study Osmotic Stress in Lignan-Deficient Flax

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 767
Author(s):  
Kamar Hamade ◽  
Ophélie Fliniaux ◽  
Jean-Xavier Fontaine ◽  
Roland Molinié ◽  
Elvis Otogo Nnang ◽  
...  
Keyword(s):  
Stress Response ◽  
Osmotic Stress ◽  
Biosynthetic Pathway ◽  
Potential Role ◽  
Plant Secondary Metabolites ◽  
Wild Type ◽  
Osmotic Stress Response ◽  
Transgenic Flax ◽  
Insight Into

Lignans, phenolic plant secondary metabolites, are derived from the phenylpropanoid biosynthetic pathway. Although, being investigated for their health benefits in terms of antioxidant, antitumor, anti-inflammatory and antiviral properties, the role of these molecules in plants remains incompletely elucidated; a potential role in stress response mechanisms has been, however, proposed. In this study, a non-targeted metabolomic analysis of the roots, stems, and leaves of wild-type and PLR1-RNAi transgenic flax, devoid of (+) secoisolariciresinol diglucoside ((+) SDG)—the main flaxseed lignan, was performed using 1H-NMR and LC-MS, in order to obtain further insight into the involvement of lignan in the response of plant to osmotic stress. Results showed that wild-type and lignan-deficient flax plants have different metabolic responses after being exposed to osmotic stress conditions, but they both showed the capacity to induce an adaptive response to osmotic stress. These findings suggest the indirect involvement of lignans in osmotic stress response.

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