Identification of 23 complementation groups required for post-translational events in the yeast secretory pathway

Regulation of tyrosine phosphorylation is a critical control point for integration of environmental signals into cellular responses. This regulation is mediated by the reciprocal actions of protein tyrosine kinases and phosphatases. CD45, the first and prototypic receptor-like protein tyrosine phosphatase, is expressed on all nucleated hematopoietic cells and plays a central role in this process. Studies of CD45 mutant cell lines, CD45-deficient mice, and CD45-deficient humans initially demonstrated the essential role of CD45 in antigen receptor signal transduction and lymphocyte development. It is now known that CD45 also modulates signals emanating from integrin and cytokine receptors. Recent work has focused on regulation of CD45 expression and alternative splicing, isoform-specific differences in signal transduction, and regulation of phosphatase activity. From these studies, a model is emerging in which CD45 affects cellular responses by controlling the relative threshold of sensitivity to external stimuli. Perturbation of this function may contribute to autoimmunity, immunodeficiency, and malignancy. Moreover, recent advances suggest that modulation of CD45 function can have therapeutic benefit in many disease states.

CD45: A Critical Regulator of Signaling Thresholds in Immune Cells

INTRODUCTION 187 Hypothetical Set of Virulence Genes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . 188 Commensal or Opportunistic Pathogen? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188 Purpose of Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 HYPHAL PRODUCTION 190 Early Observation . . . . . . . . . .. . . , .... .. .. . . . . .. . . .. .. ...... . . . . . . . . .. . . . . . . .. .. . . . . . ,. 190 Inherent Experimental Diff iculties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . 191 Recent Observations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . 193 Other Approaches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197 PROTEINASE ACTIVITy 197 Is There Only One Proteinase? 198 Evidence For and Against Proteinase . .... . . . . . . . . . . . . . . ....... ... . . . . . . ....... . . . . . .... . . ... 1 99 ADHERENCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . 203 Classification of Receptor-Ligand Molecules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204 How Many Receptor-Ligand Molecules on C. albicans Are There? . . . . . . . . . . . . . . .... . 205 Virulence Role . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206 VARIABILITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207 Chromosomal Instabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208 Antigenic Variabilit y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . 208 OTHER ATTRIBUTES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ,.. . . ...... . . . . . 209 Suppression-Activation of Host-Acquired Specific Immunity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209 CONCLUDING REMARKS 209

Putative virulence factors of Candida albicans.

Overview of N- and O-linked oligosaccharide structures found in various yeast species.

Yeasts, which have been a component of the human diet for at least 7,000 years, possess an elaborate cell wall α-mannan The influence of yeast mannan on the ecology of the human microbiota is unknown Here we show that yeast α-mannan is a viable food source for the Gram-negative bacterium Bacteroides thetaiotaomicron, a dominant member of the microbiota Detailed biochemical analysis and targeted gene disruption studies support a model whereby limited cleavage of α-mannan on the surface generates large oligosaccharides that are subsequently depolymerized to mannose by the action of periplasmic enzymes Co-culturing studies showed that metabolism of yeast mannan by B thetaiotaomicron presents a 'selfish' model for the catabolism of this difficult to breakdown polysaccharide Genomic comparison with B thetaiotaomicron in conjunction with cell culture studies show that a cohort of highly successful members of the microbiota has evolved to consume sterically-restricted yeast glycans, an adaptation that may reflect the incorporation of eukaryotic microorganisms into the human diet

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Human gut Bacteroidetes can utilize yeast mannan through a selfish mechanism

Genetic control of yeast mannan structure. Isolation and characterization of mannan mutants.

Polymorphism of the Somatic Antigen of Yeast

Characterization of a yeast mannan containing N-acetyl-D-glucosamine as an immunochemical determinant.

http://www.jbc.org/content/248/13/4667.full.pdf

Genetic control of yeast mannan structure. Complementation studies and properties of mannan mutants.

The mannans of Saccharomyces chevalieri, S. italicus, S. diastaticus, and S. carlsbergensis, were acetolyzed, and the fragments were separated by gel filtration. All gave similar acetolysis fingerprints, which were distinguished from S. cerevisiae by the presence of a pentasaccharide component in addition to the mono-, di-, tri-, and tetrasaccharides. All oligosaccharide fragments were composed of mannose in alpha-linkage. From methylation analysis and other structural studies, the disaccharide was shown to be alphaMan(1 --> 2)Man; the trisaccharide was shown to be a mixture of alphaMan(1 --> 2)alphaMan (1 --> 2)Man and alphaMan(1 --> 3)alphaMan(1 --> 2)Man; the tetrasaccharide was alphaMan(1 --> 3)alphaMan(1 --> 2)alphaMan(1 --> 2)Man; and the pentasaccharide was alphaMan(1 --> 3)alphaMan(1 --> 3)alphaMan(1 --> 2)alphaMan(1 --> 2)Man. The ratios of the different fragments varied slightly from strain to strain. Mannanase digestion of two of the mannans yielded polysaccharide residues that were unbranched (1 --> 6)-linked polymers, thus establishing the structural relationship between these mannans and that from S. cerevisiae. Antisera raised against the various yeasts cross-reacted with the mannans from each, and also with S. cerevisae mannan. The mannotetraose and mannopentaose acetolysis fragments gave complete inhibition of the precipitin reactions, which indicated that, in these systems as in the S. cerevisiae system, the terminal alpha(1 --> 3)-linked mannose unit was the principal immunochemical determinant on the cell surface.

Structure and Immunochemistry of the Cell Wall Mannans from Saccharomyces chevalieri, Saccharomyces italicus, Saccharomyces diastaticus, and Saccharomyces carlsbergensis

William C. Raschke

Papers

Genetic control of yeast mannan structure. Isolation and characterization of mannan mutants.

Polymorphism of the Somatic Antigen of Yeast

Characterization of a yeast mannan containing N-acetyl-D-glucosamine as an immunochemical determinant.

Genetic control of yeast mannan structure. Complementation studies and properties of mannan mutants.

Structure and Immunochemistry of the Cell Wall Mannans from Saccharomyces chevalieri, Saccharomyces italicus, Saccharomyces diastaticus, and Saccharomyces carlsbergensis