Mannosyltransferase activities in membranes from various yeast strains

Verostek, Mary Frances; Trimble, Robert B.

doi:10.1093/glycob/5.7.671

Cited by 37 publications

(26 citation statements)

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“…These apparently accumulate as biosynthetic end products because of their failure to be elongated significantly by Ochlp (55) and serve in the Golgi as substrates for peripheral ␣1,2-Man elongation (69), as well as capping with ␣1,3-Man by Mnnlp (70), and Man ␣1,3Man ␣1,3 elongation by additional ␣1,3-mannosyltransferases (71).…”

Section: Discussionmentioning

confidence: 99%

The Yeast ALG11 Gene Specifies Addition of the Terminal α1,2-Man to the Man5GlcNAc2-PP-dolicholN-Glycosylation Intermediate Formed on the Cytosolic Side of the Endoplasmic Reticulum

Cipollo

Trimble

Hee

et al. 2001

Journal of Biological Chemistry

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The initial steps in N-linked glycosylation involve the synthesis of a lipid-linked core oligosaccharide followed by the transfer of the core glycan to nascent polypeptides in the endoplasmic reticulum (ER). Here, we describe alg11, a new yeast glycosylation mutant that is defective in the last step of the synthesis of the Man 5 GlcNAc 2 -PP-dolichol core oligosaccharide on the cytosolic face of the ER. A deletion of the ALG11 gene leads to poor growth and temperature-sensitive lethality. In an alg11 lesion, both Man 3 GlcNAc 2 -PP-dolichol and Man 4 GlcNAc 2 -PP-dolichol are translocated into the ER lumen as substrates for the Man-P-dolichol-dependent sugar transferases in this compartment. This leads to a unique family of oligosaccharide structures lacking one or both of the lower arm ␣1,2-linked Man residues. The former are elongated to mannan, whereas the latter are poor substrates for outerchain initiation by Ochlp (Nakayama, K.-I., Nakanishi-Shindo, Y., Tanaka, A., Haga-Toda, Y., and Jigami, Y. (1997) FEBS Lett. 412, 547-550) and accumulate largely as truncated biosynthetic end products. The ALG11 gene is predicted to encode a 63.1-kDa membrane protein that by indirect immunofluorescence resides in the ER. The Alg11 protein is highly conserved, with homologs in fission yeast, worms, flies, and plants. In addition to these Alg11-related proteins, Alg11p is also similar to Alg2p, a protein that regulates the addition of the third mannose to the core oligosaccharide. All of these Alg11-related proteins share a 23-amino acid sequence that is found in over 60 proteins from bacteria to man whose function is in sugar metabolism, implicating this sequence as a potential sugar nucleotide binding motif.

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Section: Discussionmentioning

confidence: 99%

The Yeast ALG11 Gene Specifies Addition of the Terminal α1,2-Man to the Man5GlcNAc2-PP-dolicholN-Glycosylation Intermediate Formed on the Cytosolic Side of the Endoplasmic Reticulum

Cipollo

Trimble

Hee

et al. 2001

Journal of Biological Chemistry

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“…In addition, several genetic screens have identified yeast mutations that cause defects in the synthesis of mannan including the mnn (mannan), och (outer chain), ngd (N-glycosylation defective), and ldb (low dye binding) sets of mutants (16 -19). Finally, it has been possible to identify mannosyltransferase activities in yeast extracts and, in some cases, correlate these to the products of genes identified in the above screens (20,21). From these studies, a basic pathway has emerged.…”

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confidence: 99%

“…Of the enzymes involved in synthesizing the mannose branches, that responsible for adding the final ␣-1,3-linked mannose has been identified as the product of the MNN1 gene (20,25,26). Some of the branches also receive phosphomannan * The costs of publication of this article were defrayed in part by the payment of page charges.…”

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confidence: 99%

Identification of the MNN2 and MNN5Mannosyltransferases Required for Forming and Extending the Mannose Branches of the Outer Chain Mannans of Saccharomyces cerevisiae

Rayner

Munro

1998

Journal of Biological Chemistry

112

102

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The mannan structure found on the N-linked glycans of the yeast Saccharomyces cerevisiae is composed of a long backbone of ␣-1,6-linked mannose to which are attached branches consisting of two ␣-1,2-linked mannoses followed by an ␣-1,3-linked mannose. In the mutants mnn2 and mnn5, the addition of the first and second of these two mannoses, respectively, is defective. In this paper, we report the identification of the genes corresponding to these mutations. The two genes encode closely related proteins with distant homology to the known Mnn1p ␣-1,3-mannosyltransferase. We show that these proteins are localized in an early compartment of the yeast Golgi and that they are not physically associated with each other or with the two protein complexes known to be involved in synthesizing the ␣-1,6-linked backbone. The identification of Mnn2p and Mnn5p allows us to assign Golgi proteins to all of the catalytic steps in S. cerevisiae mannan synthesis.The N-linked oligosaccharides on the glycoproteins of the yeast Saccharomyces cerevisiae exist in two major forms, which differ in the length of a mannose outer chain attached to the N-linked core (1, 2). The glycoproteins of the internal compartments have a single ␣-1,6-linked mannose attached to one arm of the core, to which two or three further mannoses may be added (3, 4). In contrast, many of the proteins of the cell wall and periplasmic space have attached at the same position a large "mannan" structure of up to 200 mannoses. This consists of a long ␣-1,6-linked backbone with branches of up to three residues in length, the first two being ␣-1,2-linked and the final one being ␣-1,3-linked (Fig. 1A) (1, 3, 5). In addition, a phosphomannose residue is attached to the first mannose on some of the branches. The large amount of mannose in this structure results in mannoproteins being 40% of the dry weight of the cell wall (6). These mannans are thought to shield the cell from digestive enzymes and neutralizing antibodies, to contribute to cell wall integrity, and to serve as ligands for cell-cell associations such as flocculation and host cell attachment during invasive growth (6 -8). For the soluble proteins of the periplasmic space, the large sugar structures may prevent loss through the cell wall by contributing to hydrodynamic volume. Similar large mannose-containing oligosaccharides are also found on the cell wall proteins of many fungi and yeasts including Aspergillus, Candida, Fusarium, Schizosaccharomyces, and Trichophyton, suggesting that they are a general feature of yeast and fungi (9 -13). The backbone is usually ␣-1,6-linked mannose, and the first branch is usually an ␣-1,2-linked mannose, but the rest of the side chain varies greatly between species. Mannoses of varying number can be present in a variety of linkages, and other sugars can be incorporated including N-acetylglucosamine and galactose. This variation of the side chain may reflect evolutionary pressures to evade cell walldigesting hydrolases, immune responses, and sugar-binding killer toxins from othe...

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“…The methylotrophic yeast P. pastoris is an excellent host for heterologous protein expression [29,30]. However, P. pastoris is capable of adding both O-and N-linked carbohydrate moieties to proteins [31,32], which may lead to a glycosylation state substantially different from that found in other inulinase producers. Such post-translational modification by P. pastoris improved the global stability of the product and conferred a higher rKmINU specific activity.…”

Section: Discussionmentioning

confidence: 99%

High-level secretory expression and characterization of the recombinant Kluyveromyces marxianus inulinase

Zhang

Yang

Wang

et al. 2012

Process Biochemistry

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Mannosyltransferase activities in membranes from various yeast strains

Cited by 37 publications

References 0 publications

The Yeast ALG11 Gene Specifies Addition of the Terminal α1,2-Man to the Man5GlcNAc2-PP-dolicholN-Glycosylation Intermediate Formed on the Cytosolic Side of the Endoplasmic Reticulum

The Yeast ALG11 Gene Specifies Addition of the Terminal α1,2-Man to the Man5GlcNAc2-PP-dolicholN-Glycosylation Intermediate Formed on the Cytosolic Side of the Endoplasmic Reticulum

Identification of the MNN2 and MNN5Mannosyltransferases Required for Forming and Extending the Mannose Branches of the Outer Chain Mannans of Saccharomyces cerevisiae

High-level secretory expression and characterization of the recombinant Kluyveromyces marxianus inulinase

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