Structures of the Glycosyl-phosphatidylinositol Anchors of Porcine and Human Renal Membrane Dipeptidase

Brewis, Ian Andrew; Ferguson, Michael A. J.; Mehlert, Angela; Turner, Anthony J.; Hooper, Nigel M.

doi:10.1074/jbc.270.39.22946

Cited by 123 publications

(57 citation statements)

References 68 publications

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“…In support of this notion, a fourth mannose is present on 7 of 10 characterized mammalian protein-bound GPIs (6, 7, 26 -31, 41, 42). Six of the 7 Man 4 -GPIs were isolated from proteins purified directly from primary sources like homogenized organ tissue (6,26,28,29,31) or urine (27). Only 1 was from a protein purified from a cultured mouse cell line (30).…”

Section: Discussionmentioning

confidence: 99%

Human Smp3p Adds a Fourth Mannose to Yeast and Human Glycosylphosphatidylinositol Precursors in Vivo

Taron

Colussi

Wiedman³

et al. 2004

Journal of Biological Chemistry

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Yeast and human glycosylphosphatidylinositol (GPI) precursors differ in the extent to which a fourth mannose is present as a side branch of the third core mannose. A fourth mannose addition to GPIs has scarcely been detected in studies of mammalian GPI synthesis but is an essential step in the Saccharomyces cerevisiae pathway. We report that human SMP3 encodes a functional homolog of the yeast Smp3 GPI fourth mannosyltransferase. Expression of hSMP3 in yeast complements growth and biochemical defects of smp3 mutants and permits in vivo mannosylation of trimannosyl (Man 3 )-GPIs. Immunolocalization shows that hSmp3p resides in the endoplasmic reticulum in human cells. Northern analysis of mRNA from human tissues and cell lines indicates that hSMP3 is expressed in most tissues, with the highest levels in brain and colon, but its mRNA is nearly absent from cultured human cell lines. Correspondingly, increasing expression of hSMP3 in cultured HeLa cells causes abundant formation of three putative tetramannosyl (Man 4 )-GPIs. Our data indicate that hSmp3p functions as a mannosyltransferase that adds a fourth mannose to certain Man 3 -GPIs during biosynthesis of the human GPI precursor, and suggest it may do so in a tissue-specific manner.Glycosylphosphatidylinositols (GPIs) 1 are essential glycolipids synthesized by all eukaryotes. Many GPIs become covalently attached to the carboxyl termini of various secretory proteins and serve to anchor them to the exterior face of the plasma membrane (1, 2). Others remain protein-free and are distributed in the membranes of major cellular organelles and the plasma membrane (3, 4). GPIs are synthesized in the endoplasmic reticulum (ER) by stepwise addition of components to phosphatidylinositol. The end product of GPI synthesis is a "complete precursor" (5) that is substrate for the GPI transamidase complex that attaches it to proteins. Many of the steps and enzymes of GPI precursor assembly are conserved between humans and Saccharomyces cerevisiae and produce precursors with a common core structure of EthN-PO 4 -6Man␣1,2Man␣1,6Man␣1,4GlcN␣1,6Ins-PO 4 -lipid. In both pathways, the glycan portion of the GPI may be modified further with side branching ethanolamine phosphate (EthN-P) moieties on the first and second mannoses (6 -19).A notable difference in GPI structure between yeast and mammals is the extent to which a fourth mannose (Man-4) is present as a ␣1,2-linked side branch of the third mannose (Man-3). In S. cerevisiae, late stage intermediates in GPI precursor synthesis (17, 19 -21), the presumed GPI transamidase substrates (5), and protein-bound GPIs (22) all contain four mannoses. Addition of Man-4 to trimannosyl-GPIs (Man 3 -GPIs) by the essential Smp3 mannosyltransferase is a mandatory step in yeast GPI precursor assembly which precedes the addition of the terminal EthN-P to Man-3 through which the GPI is ultimately attached to protein (23). Thus, it is probable that all yeast GPI transamidase substrates bear four mannoses. Conversely, studies of the synthesis of mammal...

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Section: Discussionmentioning

confidence: 99%

Human Smp3p Adds a Fourth Mannose to Yeast and Human Glycosylphosphatidylinositol Precursors in Vivo

Taron

Colussi

Wiedman³

et al. 2004

Journal of Biological Chemistry

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“…However, definitive conclusions that relate GPI anchor structure and function have been difficult to draw. When produced in cells, GPI-anchored proteins exist as heterogeneous mixtures with considerable variation in their glycan core modifications and lipid moieties, a complicating feature with respect to functional analysis (1,(7)(8)(9). Furthermore, well defined modifications to the GPI anchor structure cannot be imposed by using conventional biological methods; the biosynthetic enzymes are not well characterized, and their disruption in cells simply leads to loss of the entire GPI structure (24)(25)(26)(27)(28)(29).…”

mentioning

confidence: 99%

“…1A) (1,2). The phosphoinositol, glucosamine, and mannose residues within the glycan core can be variously modified with phosphoethanolamine groups and other sugars (1,(7)(8)(9). Such complexity would be expected to encode diverse functional capability beyond membrane insertion (2,10,11).…”

mentioning

confidence: 99%

A chemical approach to unraveling the biological function of the glycosylphosphatidylinositol anchor

Paulick¹,

Forstner²,

Groves

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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The glycosylphosphatidylinositol (GPI) anchor is a C-terminal posttranslational modification found on many eukaryotic proteins that reside in the outer leaflet of the cell membrane. The complex and diverse structures of GPI anchors suggest a rich spectrum of biological functions, but few have been confirmed experimentally because of the lack of appropriate techniques that allow for structural perturbation in a cellular context. We previously synthesized a series of GPI anchor analogs with systematic deletions within the glycan core and coupled them to the GFP by a combination of expressed protein ligation and native chemical ligation Here we investigate the behavior of these GPI-protein analogs in living cells. These modified proteins integrated into the plasma membranes of a variety of mammalian cells and were internalized and directed to recycling endosomes similarly to GFP bearing a native GPI anchor. The GPI-protein analogs also diffused freely in cellular membranes. However, changes in the glycan structure significantly affected membrane mobility, with the loss of monosaccharide units correlating to decreased diffusion. Thus, this cellular system provides a platform for dissecting the contributions of various GPI anchor components to their biological function. cellular diffusion ͉ glycosylphosphatidylinositol-protein analogs ͉ intracellular trafficking ͉ GFP-GPI ͉ GPI glycan core

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“…β-1,4-linked N-acetylgalactosamine (GalNAc) is attached to Man1 in a fraction of GPI-anchored proteins (3,58,59). The GalNAc modification has not yet been observed in GPI precursors, suggesting that it is added after the attachment of GPI to proteins.…”

Section: C-5 Other Remodeling Reactionsmentioning

confidence: 99%

“…The GalNAc modification has not yet been observed in GPI precursors, suggesting that it is added after the attachment of GPI to proteins. The GalNAc residue can be further modified by a galactose (Gal) with or without a sialic acid (Neu5Ac) in some GPI-anchored proteins such as hamster prion and porcine membrane dipeptidase (44,58). It has been reported that GPIanchored proteins contain βGlcNAc phosphate linked to Man2 (60).…”

Section: C-5 Other Remodeling Reactionsmentioning

confidence: 99%

Potential Roles of GPI-Anchor Remodeling in Protein Trafficking and Raft Association in Mammalian Cells

Fujita

2012

TIGG

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Post-translational modification of proteins with glycosylphosphatidylinositol (GPI) is mediated by a mechanism that is conserved in all eukaryotes. GPI-anchored proteins are characterized by their association with specialized membrane domains called "lipid rafts," and the GPI-anchors are thought to regulate their intracellular trafficking pathways. These characteristics are regulated by the structural properties of GPI-anchors, remodeling enzymes and recognition molecules. The biogenesis of GPI-anchored proteins occurs in the ER, following which they are transported to the plasma membrane via the Golgi apparatus. During transport, the structures of the GPI-anchors are remodeled. In this minireview, the structural remodeling of mammalian GPIanchors and regulation of the transport and localization of GPI-anchored proteins are described.

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Structures of the Glycosyl-phosphatidylinositol Anchors of Porcine and Human Renal Membrane Dipeptidase

Cited by 123 publications

References 68 publications

Human Smp3p Adds a Fourth Mannose to Yeast and Human Glycosylphosphatidylinositol Precursors in Vivo

Human Smp3p Adds a Fourth Mannose to Yeast and Human Glycosylphosphatidylinositol Precursors in Vivo

A chemical approach to unraveling the biological function of the glycosylphosphatidylinositol anchor

Potential Roles of GPI-Anchor Remodeling in Protein Trafficking and Raft Association in Mammalian Cells

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