Yeast Glucan Remodeling Protein Bgl2p: Amyloid Properties and the Mode of Attachment in Cell Wall.

Bgl2p is a major, conservative, constitutive glucanosyltransglycosylase of the yeast cell wall (CW) with amyloid amino acid sequences, strongly non-covalently anchored in CW, but is able to leave it. In the environment, Bgl2p can form fibrils and/or participate in biofilm formation. Despite a long study, the question of how Bgl2p is anchored in CW remains unclear.

Importance of Non-Covalent Interactions in Yeast Cell Wall Molecular Organization.

This review covers a group of non-covalently associated molecules, particularly proteins (NCAp), incorporated in the yeast cell wall (CW) with neither disulfide bridges with proteins covalently attached to polysaccharides nor other covalent bonds. Most NCAp, particularly Bgl2, are polysaccharide-remodeling enzymes. Either directly contacting their substrate or appearing as CW lipid-associated molecules, such as in vesicles, they represent the most movable enzymes and may play a central role in CW biogenesis.

Effect of Deletions of the Genes Encoding Pho3p and Bgl2p on Polyphosphate Level, Stress Adaptation, and Attachments of These Proteins to Saccharomyces cerevisiae Cell Wall.

Inorganic polyphosphates (polyP), according to literature data, are involved in the regulatory processes of molecular complex of the Saccharomyces cerevisiae cell wall (CW). The aim of the work was to reveal relationship between polyP, acid phosphatase Pho3p, and the major CW protein, glucanosyltransglycosylase Bgl2p, which is the main glucan-remodelling enzyme with amyloid properties. It has been shown that the yeast cells with deletion of the PHO3 gene contain more high molecular alkali-soluble polyP and are also more resistant to exposure to alkali and manganese ions compared to the wild type strain.

The Post-Translational Modifications, Localization, and Mode of Attachment of Non-Covalently Bound Glucanosyltransglycosylases of Yeast Cell Wall as a Key to Understanding their Functioning.

Glucan linked to proteins is a natural mega-glycoconjugate (mGC) playing the central role as a structural component of a yeast cell wall (CW). Regulation of functioning of non-covalently bound glucanosyltransglycosylases (ncGTGs) that have to remodel mGC to provide CW extension is poorly understood. We demonstrate that the main ncGTGs Bgl2 and Scw4 have phosphorylated and glutathionylated residues and are represented in CW as different pools of molecules having various firmness of attachment.

Amyloidogenic Propensities of Ribosomal S1 Proteins: Bioinformatics Screening and Experimental Checking.

Structural S1 domains belong to the superfamily of oligosaccharide/oligonucleotide-binding fold domains, which are highly conserved from prokaryotes to higher eukaryotes and able to function in RNA binding. An important feature of this family is the presence of several copies of the structural domain, the number of which is determined in a strictly limited range from one to six. Despite the strong tendency for the aggregation of several amyloidogenic regions in the family of the ribosomal S1 proteins, their fibril formation process is still poorly understood.

[Molecular Organization of Yeast Cell Envelope].

This review summarizes the main achievements of recent years in molecular organization research of yeast cell surface, i.e., the compartment that consists of the coordinately functioning plasma membrane, periplasmic space, and cell wall.

GPI-Modified Proteins Non-covalently Attached to Saccharomyces cerevisiae Yeast Cell Wall.

Yeast cell wall GPI-anchored proteins lack the lipid part of the anchor and are covalently bound to the high-molecular-weight polysaccharides glucan and/or chitin through the mannose residues. They perform many functions, including participation in the cell wall molecular ensemble formation and providing cell resistance to stress. In this work, we identified a pool of GPI-modified proteins firmly bound to the cell wall by non-covalent interactions with the high-molecular-weight structural polysaccharides.

Dissection of differential vanadate sensitivity in two Ogataea species links protein glycosylation and phosphate transport regulation.

The closely related yeasts Ogataea polymorpha and O. parapolymorpha differ drastically from each other by sensitivity to the toxic phosphate analog vanadate. Search for genes underlying this difference revealed two genes, one designated as ABV1 (Alcian Blue staining, Vanadate resistance), which encodes a homologue of Saccharomyces cerevisiae Mnn4 responsible for attachment of mannosylphosphate to glycoside chains of secretory proteins, and the other designated as its S.

C-Terminal sequence is involved in the incorporation of Bgl2p glucanosyltransglycosylase in the cell wall of Saccharomyces cerevisiae.

A cell wall (CW) provides a protective barrier for a yeast cell and is a firm structure that nevertheless dynamically changes during cell's growth. Bgl2p is a non-covalently anchored glucanosyltransglycosylase in the CW of the yeast Saccharomyces cerevisiae. The mode of its anchorage is poorly understood, while its association with CW components is tight and resistant to 1-h treatment with 1% SDS at 37°C.

Structural model of amyloid fibrils for amyloidogenic peptide from Bgl2p-glucantransferase of S. cerevisiae cell wall and its modifying analog. New morphology of amyloid fibrils.

We performed a comparative study of the process of amyloid formation by short homologous peptides with a substitution of aspartate for glutamate in position 2 - VDSWNVLVAG (AspNB) and VESWNVLVAG (GluNB) - with unblocked termini. Peptide AspNB (residues 166-175) corresponded to the predicted amyloidogenic region of the protein glucantransferase Bgl2 from the Saccharomyces cerevisiae cell wall. The process of amyloid formation was monitored by fluorescence spectroscopy (FS), electron microscopy (EM), tandem mass spectrometry (TMS), and X-ray diffraction (XD) methods.

Amiodarone induces cell wall channel formation in yeast Hansenula polymorpha.

The yeast cell wall is constantly remodeled to enable cell growth and division. In this study, we describe a novel type of cell wall modification. We report that the drug amiodarone induces rapid channel formation within the cell wall of the yeast Hansenula polymorpha.

[Export of an invertase by yeast cells (Candida utilis)].

Export and accumulation of various forms of invertase (EC 3.2.1.

The ABCA1 domain responsible for interaction with HIV-1 Nef is conformational and not linear.

HIV-1 Nef is an accessory protein responsible for inactivation of a number of host cell proteins essential for anti-viral immune responses. In most cases, Nef binds to the target protein and directs it to a degradation pathway. Our previous studies demonstrated that Nef impairs activity of the cellular cholesterol transporter, ABCA1, and that Nef interacts with ABCA1.

Amyloidogenic peptides of yeast cell wall glucantransferase Bgl2p as a model for the investigation of its pH-dependent fibril formation.

The pH-dependence of the ability of Bgl2p to form fibrils was studied using synthetic peptides with potential amyloidogenic determinants (PADs) predicted in the Bgl2p sequence. Three PADs, FTIFVGV, SWNVLVA and NAFS, were selected on the basis of combination of computational algorithms. Peptides AEGFTIFVGV, VDSWNVLVAG and VMANAFSYWQ, containing these PADs, were synthesized.

Inactivation of Pmc1 vacuolar Ca(2+) ATPase causes G(2) cell cycle delay in Hansenula polymorpha.

The vacuolar Ca(2+) ATPase Pmc1 is involved in maintenance of a low Ca(2+) concentration in cytosol in yeast cells. Here we observed that increase of Ca(2+) cytosolic concentration in yeast Hansenula polymorpha due to inactivation of Pmc1 resulted in sensitivity to sodium dodecyl sulfate (SDS). To elucidate the mechanisms of the observed effect, a screening for mutations suppressing SDS sensitivity of the H.

Revealing of Saccharomyces cerevisiae yeast cell wall proteins capable of binding thioflavin T, a fluorescent dye specifically interacting with amyloid fibrils.

Proteins binding thioflavin T leading to its specific fluorescence were discovered in a fraction of noncovalently bound Saccharomyces cerevisiae yeast cell wall mannoproteins. Thioflavin-binding proteins display high resistance to trypsin digestion in solution. These data are the first experimental evidence for the presence of proteins whose properties are characteristic of amyloids in yeast cell wall, except for data on glucanotransferase Bgl2p that has amyloid properties.

Amyloid-like properties of Saccharomyces cerevisiae cell wall glucantransferase Bgl2p: prediction and experimental evidences.

Glucantransferase Bgl2p is a major conserved cell wall constituent described for a wide range of yeast species. In the baker's yeast Saccharomyces cerevisiae it is the only non-covalently bound cell wall protein that cannot be released from cell walls by sequential SDS and trypsin treatment. It contains seven amyloidogenic determinants.

Mutation of the protein-O-mannosyltransferase enhances secretion of the human urokinase-type plasminogen activator in Hansenula polymorpha.

Human urokinase-type plasminogen activator (uPA) is poorly secreted and aggregates in the endoplasmic reticulum of yeast cells due to inefficient folding. A screen for Hansenula polymorpha mutants with improved uPA secretion revealed a gene encoding a homologue of the Saccharomyces cerevisiae protein-O-mannosyltransferase Pmt1p. Expression of the H.

Defect of vacuolar protein sorting stimulates proteolytic processing of human urokinase-type plasminogen activator in the yeast Hansenula polymorpha.

Human urokinase-type plasminogen activator (uPA) is poorly secreted by yeast cells. Here, we have selected Hansenula polymorpha mutants with increased productivity of active extracellular uPA. Several of the obtained mutants also demonstrated a defect of sorting of carboxypeptidase Y to the vacuole and the mutant loci have been identified in six of them.

Deletion of BGL2 results in an increased chitin level in the cell wall of Saccharomyces cerevisiae.

It is shown that the deletion of BGL2 gene leads to increase in chitin content in the cell wall of Saccharomyces cerevisiae. A part of the additional chitin can be removed from the bgl2Delta cell wall by alkali or trypsin treatment. Chitin synthase 1 (Chs1) activity was increased by 60 % in bgl2Delta mutant.