Glycoantigen expression is regulated both temporally and spatially during development in the cellular slime molds Dictyostelium discoideum and D. mucoroides

West, Christopher M.; Erdos, Gregory W.; Davis, Rosemary W.

doi:10.1007/bf00230640

Cited by 26 publications

(21 citation statements)

References 42 publications

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“…We have observed this discrepancy in countin, CF50, CF45-1, and a different secreted factor, CMF (4,8,20,25). For the latter, we found that the protein is glycosylated, as has been found for many of the proteins that Dictyostelium cells secrete (41,44). It is thus possible that CF60 is also glycosylated.…”

Section: Discussionsupporting

confidence: 54%

A 60-Kilodalton Protein Component of the Counting Factor Complex Regulates Group Size in Dictyostelium discoideum

et al. 2006

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Although we were unable to obtain cells lacking CF60, decreasing CF60 levels by antisense resulted in large groups, and overexpressing CF60 resulted in small groups. When added to wild-type cells, conditioned starvation medium from CF60 overexpressor cells as well as recombinant CF60 caused the formation of small groups. The ability of recombinant CF60 to decrease group size did not require the presence of the CF component CF45-1 or countin but did require the presence of CF50. Recombinant CF60 does not have acid phosphatase activity, indicating that the CF60 bioactivity is not due to a phosphatase activity. Together, the data suggest that CF60 is a component of CF, and thus this secreted signal has four different protein components.

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Section: Discussionsupporting

confidence: 54%

A 60-Kilodalton Protein Component of the Counting Factor Complex Regulates Group Size in Dictyostelium discoideum

et al. 2006

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“…3, SP85 was recognized by the anti-carbohydrate mAb 16.1 in wild-type cells but not in either of the two mutants, and migrated more rapidly in the mutants. The absence of the carbohydrate epitope and the lower apparent M r indicate that O-glycosylation of SP85 is inhibited in the cis4c(gntB) mutant strain in the same way that it is affected by the modB mutation (17,36). A similar effect was observed for the glycosylation of SP29, which is shown in the lower M r region of panel C (Fig.…”

Section: Architecture Of the Predicted Pp ␣-Glcnac-t2supporting

confidence: 55%

Initiation of Mucin-type O-Glycosylation in Dictyostelium Is Homologous to the Corresponding Step in Animals and Is Important for Spore Coat Function

Wang

Metcalf

Wel

et al. 2003

Journal of Biological Chemistry

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Like animal cells, many unicellular eukaryotes modify mucin-like domains of secretory proteins with multiple O-linked glycans. Unlike animal mucin-type glycans, those of some microbial eukaryotes are initiated by ␣-linked GlcNAc rather than ␣-GalNAc. Based on sequence similarity to a recently cloned soluble polypeptide hydroxyproline GlcNAc-transferase that modifies Skp1 in the cytoplasm of the social ameba Dictyostelium, we have identified an enzyme, polypeptide ␣-N-acetylglucosaminyltransferase (pp ␣-GlcNAc-T2), that attaches GlcNAc to numerous secretory proteins in this organism. Unlike the Skp1 GlcNAc-transferase, pp ␣-GlcNAc-T2 is predicted to be a type 2 transmembrane protein. A highly purified, soluble, recombinant fragment of pp ␣-GlcNAc-T2 efficiently transfers GlcNAc from UDP-GlcNAc to synthetic peptides corresponding to mucin-like domains in two proteins that traverse the secretory pathway. pp ␣-GlcNAc-T2 is required for addition of GlcNAc to peptides in cell extracts and to the proteins in vivo. Mass spectrometry and Edman degradation analyses show that pp ␣-GlcNAc-T2 attaches GlcNAc in ␣-linkage to the Thr residues of all the synthetic mucin repeats. pp ␣-GlcNAc-T2 is encoded by the previously described modB locus defined by chemical mutagenesis, based on sequence analysis and complementation studies. This finding establishes that the many phenotypes of modB mutants, including a permeability defect in the spore coat, can now be ascribed to defects in mucin-type O-glycosylation. A comparison of the sequences of pp ␣-GlcNAc-T2 and the animal pp ␣-GalNAc-transferases reveals an ancient common ancestry indicating that, despite the different N-acetylhexosamines involved, the enzymes share a common mechanism of action.

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“…Although internal Fuc linkages have been found in glycoproteins (33,34), the outer Gal␣136Gal␣13 Fuc cap structure has not been previously described. However, this sugar chain is not immunogenic in mice (18), unlike other Dictyostelium sugar protein conjugates (35,36), suggesting that a similar structure may be expressed in mammals. The linkage amino acid, hydroxyproline, is possibly 4-hydroxylated based on the specificity of a SKP1:UDP-GlcNAc GlcNAc-transferase activity that has been detected and partially purified.…”

Section: Discussionmentioning

confidence: 96%

The Cytoplasmic F-box Binding Protein SKP1 Contains a Novel Pentasaccharide Linked to Hydroxyproline inDictyostelium

Teng-umnuay

Morris²,

Dell³

et al. 1998

Journal of Biological Chemistry

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SKP1 is involved in the ubiquitination of certain cell cycle and nutritional regulatory proteins for rapid turnover. SKP1 from Dictyostelium has been known to be modified by an oligosaccharide containing Fuc and Gal, which is unusual for a cytoplasmic or nuclear protein.To establish how it is glycosylated, SKP1 labeled with [ 3 H]Fuc was purified to homogeneity and digested with endo-Lys-C. A single radioactive peptide was found after two-dimensional high performance liquid chromatography. Analysis in a quadrupole time-of-flight mass spectrometer revealed a predominant ion with a novel mass. Tandem mass spectrometry analysis yielded a set of daughter ions which identified the peptide and showed that it was modified at Pro-143. A second series of daughter ions showed that Pro-143 was hydroxylated and derivatized with a potentially linear pentasaccharide, Hex3 Hex3 Fuc3 Hex3 HexNAc3(HyPro). The attachment site was confirmed by Edman degradation. Gas chromatography-mass spectrometry analysis of trimethylsilyl-derivatives of overexpressed SKP1 after methanolysis showed the HexNAc to be GlcNAc. Exoglycosidase digestions of the glycopeptide from normal SKP1 and from a fucosylation mutant, followed by matrix-assisted laser desorption time-of-flight mass spectrometry analysis, showed that the sugar chain consisted of D-Galp␣136-D-Galp␣13L-Fucp␣132-DGalp␤133GlcNAc. Matrix-assisted laser-desorption timeof-flight mass spectrometry analysis of all SKP1 peptides resolved by reversed phase-high performance liquid chromatography showed that SKP1 was only partially hydroxylated at Pro-143 and that all hydroxylated SKP1 was completely glycosylated. Thus SKP1 is variably modified by an unusual linear pentasaccharide, suggesting the localization of a novel glycosylation pathway in the cytoplasm.SKP1 is found in a multiprotein complex with cullin (a cdc53 homologue) and an F-box-containing protein to form the SCF complex, named as an acronym of the participating proteins. When this complex contains an E2 enzyme, it is responsible for ubiquitinating various target proteins, depending on the identity of the F-box protein. Targets for subsequent degradation identified in Saccharomyces cerevisiae include cell cycle proteins such as the S-phase kinase inhibitor SIC1 and G 1 cyclins, and proteins specific to the nutrition of the cell (1-4). The SCF complex has also been implicated in phosphorylation of kinetochore proteins (5), and another distantly related complex affects mRNA metabolism (6). An SCF complex with Cyclin A and Cdk2 has been detected in mammalian cells, and its abundance appears increased in transformed cells (7,8). SKP1 itself is abundantly and dynamically expressed in the mouse embryo (9) and central nervous system including postmitotic neurons (10) and at very high concentrations in the inner ear organ of Corti (11,12), where it comprises up to 5% of total protein in the cytoplasm. The expression of several SKP1 genes in plants appears to be governed by morphogenetic boundaries (13). Thus SKP1 is expressed ubiquitously ...

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Glycoantigen expression is regulated both temporally and spatially during development in the cellular slime molds Dictyostelium discoideum and D. mucoroides

Cited by 26 publications

References 42 publications

A 60-Kilodalton Protein Component of the Counting Factor Complex Regulates Group Size in Dictyostelium discoideum

A 60-Kilodalton Protein Component of the Counting Factor Complex Regulates Group Size in Dictyostelium discoideum

Initiation of Mucin-type O-Glycosylation in Dictyostelium Is Homologous to the Corresponding Step in Animals and Is Important for Spore Coat Function

The Cytoplasmic F-box Binding Protein SKP1 Contains a Novel Pentasaccharide Linked to Hydroxyproline inDictyostelium

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