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| Entry URI | http://metadb.riken.jp/db/SciNetS_ria224i/cria224u4ria224u16460512i |
| Entry name | Strasser Richard et al. 2006 Mar. Plant J. 45(5):789-803. |
| Title | Molecular cloning and characterization of Arabidopsis thaliana Golgi alpha-mannosidase II, a key enzyme in the formation of complex N-glycans in plants. |
| Authors | Glössl Josef|Jin Chunsheng|Mach Lukas|Schoberer Jennifer|Steinkellner Herta|Strasser Richard |
| Abstract | N-glycosylation is one of the major post-translational modifications of proteins in eukaryotes; however, the processing reactions of oligomannosidic N-glycan precursors leading to hybrid-type and finally complex-type N-glycans are not fully understood in plants. To investigate the role of Golgi alpha-mannosidase II (GMII) in the formation of complex N-glycans in plants, we identified a putative GMII from Arabidopsis thaliana (AtGMII; EC 3.2.1.114) and characterized the enzyme at a molecular level. The putative AtGMII cDNA was cloned, and its deduced amino acid sequence revealed a typical type II membrane protein of 1173 amino acids. A soluble recombinant form of the enzyme produced in insect cells was capable of processing different physiologically relevant hybrid N-glycans. Furthermore, a detailed N-glycan analysis of two AtGMII knockout mutants revealed the predominant presence of unprocessed hybrid N-glycans. These results provide evidence that AtGMII plays a central role in the formation of complex N-glycans in plants. Furthermore, conclusive evidence was obtained that alternative routes in the conversion of hybrid N-glycans to complex N-glycans exist in plants. Transient expression of N-terminal AtGMII fragments fused to a GFP reporter molecule demonstrated that the transmembrane domain and 10 amino acids from the cytoplasmic tail are sufficient to retain a reporter molecule in the Golgi apparatus and that lumenal sequences are not involved in the retention mechanism. A GFP fusion construct containing only the transmembrane domain was predominantly retained in the ER, a result that indicates the presence of a motif promoting ER export within the last 10 amino acids of the cytoplasmic tail of AtGMII. |
| Pubmed ID | 16460512 |
| Journal | The Plant journal |
| Volume | 45 |
| Issue | 5 |
| Pages | 789-803 |
| Publication date | 2006 Mar |
| Num of phenotype gene | 0 |