Restricted processing of glycans by endomannosidase in mammalian cells.
Removal of α-glucose residues from nascent glycoproteins in the early secretory pathway is a requirement for further N-glycan maturation. Although deglucosylation is a stepwise process mediated by endoplasmic reticulum-associated glucosidases I and II for most glycoproteins, Golgi endo-α-mannosidase...
| Main Authors: | , , , |
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| Format: | Journal article |
| Language: | English |
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2012
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| _version_ | 1826279581138550784 |
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| author | Kukushkin, N Easthope, I Alonzi, D Butters, T |
| author_facet | Kukushkin, N Easthope, I Alonzi, D Butters, T |
| author_sort | Kukushkin, N |
| collection | OXFORD |
| description | Removal of α-glucose residues from nascent glycoproteins in the early secretory pathway is a requirement for further N-glycan maturation. Although deglucosylation is a stepwise process mediated by endoplasmic reticulum-associated glucosidases I and II for most glycoproteins, Golgi endo-α-mannosidase provides a backup mechanism for glycoprotein deglucosylation. Although conserved in mammals, in certain cell lines, endomannosidase activity in vitro appears to differ from its activity in cells following glucosidase inhibition. Here, we show that in bovine cells this is explained by restricted substrate specificity allowing processing of Glc(1)Man(7)GlcNAc(1/2) and Glc(1)Man(5)GlcNAc(1/2) but not fully glucosylated glycans that build up when glucosidases are inhibited. Our data further demonstrate that such specificity is determined genetically rather than post-translationally. We also demonstrate that the bovine endomannosidase is transcriptionally upregulated by comparison with glucosidase II in Madin-Darby bovine kidney cells and speculate that this is to compensate for the reduced catalytic activity as measured in the recombinant form of the enzyme. |
| first_indexed | 2024-03-07T00:00:53Z |
| format | Journal article |
| id | oxford-uuid:75e8a6b3-e0c1-413c-99d8-480c6d24e507 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T00:00:53Z |
| publishDate | 2012 |
| record_format | dspace |
| spelling | oxford-uuid:75e8a6b3-e0c1-413c-99d8-480c6d24e5072022-03-26T20:12:20ZRestricted processing of glycans by endomannosidase in mammalian cells.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:75e8a6b3-e0c1-413c-99d8-480c6d24e507EnglishSymplectic Elements at Oxford2012Kukushkin, NEasthope, IAlonzi, DButters, TRemoval of α-glucose residues from nascent glycoproteins in the early secretory pathway is a requirement for further N-glycan maturation. Although deglucosylation is a stepwise process mediated by endoplasmic reticulum-associated glucosidases I and II for most glycoproteins, Golgi endo-α-mannosidase provides a backup mechanism for glycoprotein deglucosylation. Although conserved in mammals, in certain cell lines, endomannosidase activity in vitro appears to differ from its activity in cells following glucosidase inhibition. Here, we show that in bovine cells this is explained by restricted substrate specificity allowing processing of Glc(1)Man(7)GlcNAc(1/2) and Glc(1)Man(5)GlcNAc(1/2) but not fully glucosylated glycans that build up when glucosidases are inhibited. Our data further demonstrate that such specificity is determined genetically rather than post-translationally. We also demonstrate that the bovine endomannosidase is transcriptionally upregulated by comparison with glucosidase II in Madin-Darby bovine kidney cells and speculate that this is to compensate for the reduced catalytic activity as measured in the recombinant form of the enzyme. |
| spellingShingle | Kukushkin, N Easthope, I Alonzi, D Butters, T Restricted processing of glycans by endomannosidase in mammalian cells. |
| title | Restricted processing of glycans by endomannosidase in mammalian cells. |
| title_full | Restricted processing of glycans by endomannosidase in mammalian cells. |
| title_fullStr | Restricted processing of glycans by endomannosidase in mammalian cells. |
| title_full_unstemmed | Restricted processing of glycans by endomannosidase in mammalian cells. |
| title_short | Restricted processing of glycans by endomannosidase in mammalian cells. |
| title_sort | restricted processing of glycans by endomannosidase in mammalian cells |
| work_keys_str_mv | AT kukushkinn restrictedprocessingofglycansbyendomannosidaseinmammaliancells AT easthopei restrictedprocessingofglycansbyendomannosidaseinmammaliancells AT alonzid restrictedprocessingofglycansbyendomannosidaseinmammaliancells AT butterst restrictedprocessingofglycansbyendomannosidaseinmammaliancells |