The role of the membrane-spanning domain and stalk region of <i>N</i>-acetylglucosaminyltransferase I in retention, kin recognition and structural maintenance of the Golgi apparatus in HeLa cells

Nilsson, Tommy; Rabouille, Cathérine; Hui, Norman; Watson, Rose; Warren, Graham

doi:10.1242/jcs.109.7.1975

Cited by 127 publications

(5 citation statements)

References 31 publications

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“…However, the interactions observed here are of a completely different nature, being highly specific interactions between defined subsets of enzymes within the same Golgi compartment. Indeed this could also be the case for the NAGT I–mannosidase II complex as the region of NAGT I that is required for interaction with mannosidase II does not correlate to the region involved in retention (Munro, 1995; Nilsson et al ., 1996). Thus it may be that many Golgi enzymes exist in specific complexes which carry out reactions required in successive steps to generate elaborate products—as is indeed seen for many biosynthetic multi‐enzyme complexes such as fatty acid synthase.…”

Section: Discussionmentioning

confidence: 99%

Multi-protein complexes in the cis Golgi of Saccharomyces cerevisiae with alpha -1,6-mannosyltransferase activity

1998

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Anp1p, Van1p and Mnn9p constitute a family of membrane proteins required for proper Golgi function in Saccharomyces cerevisiae. We demonstrate that these proteins colocalize within the cis Golgi, and that they are physically associated in two distinct complexes, both of which contain Mnn9p. Furthermore, we identify two new proteins in the Anp1p-Mnn9p-containing complex which have homology to known glycosyltransferases. Both protein complexes have α-1,6-mannosyltransferase activity, forming a series of poly-mannose structures. These reaction products also contain some α-1,2-linked mannose residues. Our data suggest that these two multi-protein complexes are responsible for the synthesis and initial branching of the long α-1,6-linked backbone of the hypermannose structure attached to many yeast glycoproteins.

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Section: Discussionmentioning

confidence: 99%

Multi-protein complexes in the cis Golgi of Saccharomyces cerevisiae with alpha -1,6-mannosyltransferase activity

1998

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“…An example of this occurs in the Golgi complex, where resident Golgi proteins interact with each other to form oligomeric structures ( , ). The interaction between Golgi proteins was originally believed to be mediated by the transmembrane domains, yet now it appears that the regions flanking the transmembrane domain promote oligomer formation ( , ).…”

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confidence: 99%

Fragmentation of a Golgi-Localized Chimeric Protein Allows Detergent Solubilization and Reveals an Alternate Conformation of the Cytoplasmic Domain

Sevier

Machamer

1998

Biochemistry

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Golgi resident proteins maintain their localization despite a continual protein and lipid flux through the organelle. To study Golgi retention mechanisms, we have focused upon the chimeric protein Gm1. This protein contains the Golgi transmembrane domain targeting signal from the infectious bronchitis virus M protein and the lumenal and cytoplasmic domain of the vesicular stomatitis virus glycoprotein (VSV G). The Gm1 protein is targeted to the Golgi where it forms an unusually stable detergent-resistant oligomer. The formation of oligomeric structures may aid retention of Golgi resident proteins. Thus, determining the stabilization mechanism may shed light on Golgi protein retention. Previous work determined that the transmembrane domain is required for the targeting and oligomerization of Gm1, but it is the cytoplasmic tail that stabilizes the complexes [Weisz, O. A., Swift, A. M., and Machamer, C. E. (1993) J. Cell Biol. 122, 1185-1196]. However, further study of the oligomer has been difficult due to its insolubility. Here we report that fragmenting the Gm1 protein into several pieces facilitates solubilization by sodium dodecyl sulfate (SDS). By analyzing the fragments produced after cleavage, we determined that the stability of the oligomer is not caused by covalent linkage of Gm1 to itself or other proteins. The fragment corresponding to the transmembrane domain and tail of Gm1 had an enhanced mobility in SDS gels relative to the same fragment of the parent VSV G protein. The enhanced migration of the tail fragment does not reflect sequence differences or post-translational modification, but correlates with Golgi localization and oligomerization. We suggest that the enhanced mobility of the Gm1 tail fragment reflects an altered conformation which serves to stabilize the detergent-resistant oligomers.

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“…In addition, the XYLT2 zone is smaller than the GALNT6 zone based on the quantitative analysis of the data obtained by STORM. It was proposed that glycosylation enzymes were clustered by oligomerization or kin recognition 16 , 30 – 32 . However, as this is insufficient to explain the different behaviors of different zones, further investigation on the generation mechanism of the zone will be required.…”

Section: Discussionmentioning

confidence: 99%

Dynamic movement of the Golgi unit and its glycosylation enzyme zones

Harada,

Kunii,

Kurokawa

et al. 2024

Nat Commun

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Knowledge on the distribution and dynamics of glycosylation enzymes in the Golgi is essential for better understanding this modification. Here, using a combination of CRISPR/Cas9 knockin technology and super-resolution microscopy, we show that the Golgi complex is assembled by a number of small ‘Golgi units’ that have 1-3 μm in diameter. Each Golgi unit contains small domains of glycosylation enzymes which we call ‘zones’. The zones of N- and O-glycosylation enzymes are colocalised. However, they are less colocalised with the zones of a glycosaminoglycan synthesizing enzyme. Golgi units change shapes dynamically and the zones of glycosylation enzymes rapidly move near the rim of the unit. Photobleaching analysis indicates that a glycosaminoglycan synthesizing enzyme moves between units. Depletion of giantin dissociates units and prevents the movement of glycosaminoglycan synthesizing enzymes, which leads to insufficient glycosaminoglycan synthesis. Thus, we show the structure-function relationship of the Golgi and its implications in human pathogenesis.

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The role of the membrane-spanning domain and stalk region of N-acetylglucosaminyltransferase I in retention, kin recognition and structural maintenance of the Golgi apparatus in HeLa cells

Cited by 127 publications

References 31 publications

Multi-protein complexes in the cis Golgi of Saccharomyces cerevisiae with alpha -1,6-mannosyltransferase activity

Multi-protein complexes in the cis Golgi of Saccharomyces cerevisiae with alpha -1,6-mannosyltransferase activity

Fragmentation of a Golgi-Localized Chimeric Protein Allows Detergent Solubilization and Reveals an Alternate Conformation of the Cytoplasmic Domain

Dynamic movement of the Golgi unit and its glycosylation enzyme zones

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