ALG11 encodes the GDP-Man:Man3GlcNAc2-PP-Dol alpha-1,2-mannosyltransferase (EC 2.4.1.131) of S. cerevisiae, an ER membrane protein of glycosyltransferase family GT4. On the cytoplasmic face of the ER it adds two sequential alpha-1,2-linked mannoses from GDP-mannose, converting Man3GlcNAc2-PP-Dol to Man4- and then Man5GlcNAc2-PP-Dol, the last cytosolic intermediate of the N-glycan precursor before it is flipped into the ER lumen for extension by Dol-P-Man- and Dol-P-Glc-dependent enzymes. Alg11p associates with Alg1p in a mannosyltransferase complex distinct from the Alg1-Alg2 complex. alg11 deletion causes poor growth, temperature sensitivity and transfer of truncated glycans lacking the lower-arm alpha-1,2-mannoses; its activity depends on the conserved EX7E motif.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0000026 alpha-1,2-mannosyltransferase activity | IMP PMID:11278778 The yeast ALG11 gene specifies addition of the terminal alph... | ACCEPT | Summary: IMP (Cipollo et al. 2001): alg11 mutants lack the lower-arm alpha-1,2-linked mannoses, defining Alg11 as the alpha-1,2-mannosyltransferase. Correct; parent of the more specific GO:0004377. Reason: Kept ACCEPT for consistency with the RCA and TAS rows for the same term; this IMP is the experimental basis for the alpha-1,2-mannosyltransferase assignment. Supporting Evidence: PMID:11278778 This leads to a unique family of oligosaccharide structures lacking one or both of the lower arm alpha1,2-linked Man residues. PMID:11278778 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. |
| GO:0000026 alpha-1,2-mannosyltransferase activity | RCA GO_REF:0000123 | ACCEPT | Summary: RCA from YeastPathways LLO biosynthesis (two GDP-Man-dependent steps Man3->Man4->Man5GlcNAc2-PP-Dol assigned to Alg11). Correct. Supporting Evidence: PMID:19929855 In the present study we characterize Alg11 from yeast as a mannosyltransferase catalysing the sequential transfer of two alpha1,2-linked mannose residues from GDP-mannose to Man3GlcNAc2-PP-Dol and subsequently to Man4GlcNAc2-PP-Dol forming the Man5GlcNAc2-PP-Dol intermediate at the cytosolic side of the ER before flipping to the luminal side. |
| GO:0000026 alpha-1,2-mannosyltransferase activity | TAS Reactome:R-SCE-449324 | ACCEPT | Summary: TAS from Reactome R-SCE-449324 (addition of the fourth and fifth mannose by Alg11). Correct. Supporting Evidence: Reactome:R-SCE-449324 A fourth and fifth mannose is added to the N-glycan precursor skeleton by Alg11, characterized from yeast (Cipollo JF et al, 2001). |
| GO:0004377 GDP-Man:Man(3)GlcNAc(2)-PP-Dol alpha-1,2-mannosyltransferase activity | EXP PMID:19929855 Biochemical characterization, membrane association and ident... | ACCEPT | Summary: EXP (Absmanner et al. 2010): biochemical characterisation of Alg11 transferring two alpha-1,2-mannoses to Man3- and Man4GlcNAc2-PP-Dol; EX7E, Gly85/87 and Lys319 required. Supporting Evidence: PMID:19929855 In the present study we characterize Alg11 from yeast as a mannosyltransferase catalysing the sequential transfer of two alpha1,2-linked mannose residues from GDP-mannose to Man3GlcNAc2-PP-Dol and subsequently to Man4GlcNAc2-PP-Dol forming the Man5GlcNAc2-PP-Dol intermediate at the cytosolic side of the ER before flipping to the luminal side. |
| GO:0004377 GDP-Man:Man(3)GlcNAc(2)-PP-Dol alpha-1,2-mannosyltransferase activity | IBA GO_REF:0000033 | ACCEPT | Summary: IBA from PANTHER ALG11 node (yeast, S. pombe, Arabidopsis, human ALG11). Correct core activity. Supporting Evidence: PMID:19929855 In the present study we characterize Alg11 from yeast as a mannosyltransferase catalysing the sequential transfer of two alpha1,2-linked mannose residues from GDP-mannose to Man3GlcNAc2-PP-Dol and subsequently to Man4GlcNAc2-PP-Dol forming the Man5GlcNAc2-PP-Dol intermediate at the cytosolic side of the ER before flipping to the luminal side. |
| GO:0004377 GDP-Man:Man(3)GlcNAc(2)-PP-Dol alpha-1,2-mannosyltransferase activity | IDA PMID:16878994 In vitro evidence for the dual function of Alg2 and Alg11: e... | ACCEPT | Summary: IDA (O'Reilly et al. 2006): recombinant Alg11 catalyses two sequential alpha-1,2-mannosylations on chemoenzymatically prepared Man3GlcNAc2-PP-Dol. Supporting Evidence: PMID:16878994 it was thus possible to define the biochemical function of Alg11, which is to catalyze the next two sequential alpha1,2-mannosylations. |
| GO:0004377 GDP-Man:Man(3)GlcNAc(2)-PP-Dol alpha-1,2-mannosyltransferase activity | IEA GO_REF:0000120 | ACCEPT | Summary: IEA via EC 2.4.1.131 / RHEA:29523 and InterPro IPR038013. Correct. Supporting Evidence: PMID:19929855 In the present study we characterize Alg11 from yeast as a mannosyltransferase catalysing the sequential transfer of two alpha1,2-linked mannose residues from GDP-mannose to Man3GlcNAc2-PP-Dol and subsequently to Man4GlcNAc2-PP-Dol forming the Man5GlcNAc2-PP-Dol intermediate at the cytosolic side of the ER before flipping to the luminal side. |
| GO:0005515 protein binding | IPI PMID:15044395 Physical interactions between the Alg1, Alg2, and Alg11 mann... | REMOVE | Summary: IPI with Alg1 (P16661) from Gao et al. 2004. Alg11 genuinely associates with Alg1 in a mannosyltransferase complex, but 'protein binding' carries no functional information; removal does not mean the interaction is false. Reason: Uninformative MF term; the Alg1-Alg11 association is better captured as complex membership. Supporting Evidence: PMID:15044395 The two Alg1-containing complexes differ from one another in that one complex contains Alg2 and the other contains Alg11. |
| GO:0005789 endoplasmic reticulum membrane | EXP PMID:19929855 Biochemical characterization, membrane association and ident... | ACCEPT | Summary: EXP (Absmanner et al. 2010): topology and membrane-association analysis of Alg11 in the ER membrane. Supporting Evidence: PMID:19929855 this domain can be deleted without disturbing glycosyltransferase function and membrane association |
| GO:0005789 endoplasmic reticulum membrane | IBA GO_REF:0000033 | ACCEPT | Summary: IBA is_active_in ER membrane from PANTHER ALG11 node. Correct. Supporting Evidence: PMID:11278778 The ALG11 gene is predicted to encode a 63.1-kDa membrane protein that by indirect immunofluorescence resides in the ER. |
| GO:0005789 endoplasmic reticulum membrane | IDA PMID:11278778 The yeast ALG11 gene specifies addition of the terminal alph... | ACCEPT | Summary: IDA (Cipollo et al. 2001): indirect immunofluorescence places Alg11p in the ER. Supporting Evidence: PMID:11278778 The ALG11 gene is predicted to encode a 63.1-kDa membrane protein that by indirect immunofluorescence resides in the ER. |
| GO:0005789 endoplasmic reticulum membrane | IEA GO_REF:0000044 | ACCEPT | Summary: IEA from UniProt SubCell SL-0097 (ER membrane). Correct. Supporting Evidence: PMID:11278778 The ALG11 gene is predicted to encode a 63.1-kDa membrane protein that by indirect immunofluorescence resides in the ER. |
| GO:0005789 endoplasmic reticulum membrane | TAS Reactome:R-SCE-449324 | ACCEPT | Summary: TAS from Reactome R-SCE-449324 (ER membrane location of the Alg11 reaction). Correct. Supporting Evidence: Reactome:R-SCE-449324 A fourth and fifth mannose is added to the N-glycan precursor skeleton by Alg11, characterized from yeast (Cipollo JF et al, 2001). |
| GO:0005829 cytosol | RCA GO_REF:0000123 | MODIFY | Summary: RCA is_active_in cytosol from the YeastPathways LLO pathway conversion default. Alg11p is an ER membrane protein acting on dolichol-linked substrates at the cytosolic face of the ER membrane, not a soluble cytosolic enzyme. Reason: Converter compartment default; the precise site is the cytoplasmic side of the ER membrane. Proposed replacements: cytoplasmic side of endoplasmic reticulum membrane Supporting Evidence: PMID:19929855 In the present study we characterize Alg11 from yeast as a mannosyltransferase catalysing the sequential transfer of two alpha1,2-linked mannose residues from GDP-mannose to Man3GlcNAc2-PP-Dol and subsequently to Man4GlcNAc2-PP-Dol forming the Man5GlcNAc2-PP-Dol intermediate at the cytosolic side of the ER before flipping to the luminal side. PMID:11278778 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. |
| GO:0006488 dolichol-linked oligosaccharide biosynthetic process | IBA GO_REF:0000033 | ACCEPT | Summary: IBA for dolichol-linked oligosaccharide biosynthesis. Correct. Supporting Evidence: PMID:19929855 In the present study we characterize Alg11 from yeast as a mannosyltransferase catalysing the sequential transfer of two alpha1,2-linked mannose residues from GDP-mannose to Man3GlcNAc2-PP-Dol and subsequently to Man4GlcNAc2-PP-Dol forming the Man5GlcNAc2-PP-Dol intermediate at the cytosolic side of the ER before flipping to the luminal side. |
| GO:0006488 dolichol-linked oligosaccharide biosynthetic process | IDA PMID:16878994 In vitro evidence for the dual function of Alg2 and Alg11: e... | ACCEPT | Summary: IDA (O'Reilly et al. 2006): in vitro reconstitution of the Alg11 steps of the dolichol pathway. Supporting Evidence: PMID:16878994 it was thus possible to define the biochemical function of Alg11, which is to catalyze the next two sequential alpha1,2-mannosylations. |
| GO:0006488 dolichol-linked oligosaccharide biosynthetic process | IMP PMID:11278778 The yeast ALG11 gene specifies addition of the terminal alph... | ACCEPT | Summary: IMP (Cipollo et al. 2001): alg11 is defective in the last cytosolic step of Man5GlcNAc2-PP-Dol synthesis. Supporting Evidence: PMID:11278778 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. |
| GO:0006488 dolichol-linked oligosaccharide biosynthetic process | RCA GO_REF:0000123 | ACCEPT | Summary: RCA from YeastPathways LLO biosynthesis. Correct. Supporting Evidence: PMID:19929855 In the present study we characterize Alg11 from yeast as a mannosyltransferase catalysing the sequential transfer of two alpha1,2-linked mannose residues from GDP-mannose to Man3GlcNAc2-PP-Dol and subsequently to Man4GlcNAc2-PP-Dol forming the Man5GlcNAc2-PP-Dol intermediate at the cytosolic side of the ER before flipping to the luminal side. |
| GO:0009101 glycoprotein biosynthetic process | IMP PMID:11278778 The yeast ALG11 gene specifies addition of the terminal alph... | TOO GENERAL | Summary: IMP (Cipollo et al. 2001) for glycoprotein biosynthetic process: alg11 cells transfer truncated glycans to proteins. Correct but a broad parent of protein N-linked glycosylation; LLO biosynthesis is the specific process. Reason: Broad ancestor; GO:0006488 is the precise process. Supporting Evidence: PMID:11278778 This leads to a unique family of oligosaccharide structures lacking one or both of the lower arm alpha1,2-linked Man residues. |
| GO:0016757 glycosyltransferase activity | IEA GO_REF:0000002 | TOO GENERAL | Summary: IEA from InterPro IPR001296 (glycosyl transferase family 1). Correct but general. Reason: General parent of GO:0004377. |
Loading supporting content…
Download this section (compressed HTML)Q: Is Alg11 activity on Man4GlcNAc2-PP-Dol dependent on its association with Alg1, i.e. does the Alg1-Alg11 complex alter Alg11 substrate specificity or processivity?
Experiment: Compare kinetics of purified Alg11 alone versus Alg1-Alg11 co-purified complex on Man3- and Man4GlcNAc2-PP-Dol substrates.
Alpha-1,2-mannosyltransferase; catalyzes sequential addition of the two terminal alpha 1,2-mannose residues to the Man5GlcNAc2-PP-dolichol intermediate during asparagine-linked glycosylation in the ER
Loading supporting content…
Download this section (compressed HTML)Loading supporting content…
Download this section (compressed HTML)