Two soluble glycosyltransferases glycosylate less efficiently in vivo than their membrane bound counterparts

Zhu, Guofen; Allende, María L.; Jaśkiewicz, Ewa; Qian, Rong; Darling, Douglas S.; Worth, Christopher A.; Colley, Karen J.; Young, William W.

doi:10.1093/glycob/8.8.831

Cited by 29 publications

(21 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, membrane-bound glycosyltransferases interact with their membrane-bound glycolipid substrates by diffusion within the two-dimensional plane of the lipid bilayer. This explains the observation that reaction rates can become independent of the reaction volume and may obey two-dimensional enzyme kinetics (17,18).…”

Section: Ganglioside Metabolismmentioning

confidence: 86%

Combinatorial Ganglioside Biosynthesis

Kolter¹,

Proia

Sandhoff

2002

Journal of Biological Chemistry

291

212

View full text Add to dashboard Cite

Section: Ganglioside Metabolismmentioning

confidence: 86%

Combinatorial Ganglioside Biosynthesis

Kolter¹,

Proia

Sandhoff

2002

Journal of Biological Chemistry

291

212

View full text Add to dashboard Cite

“…The ability of soluble intracellular GnTI to form high molecular complexes may be important in its ability to coordinate the synthesis of complex N-glycans in Lec1 cells. The relative abilities of membranebound and soluble forms of other Golgi glycosyltransferases to glycosylate newly synthesized proteins have been compared, and differences between enzymes have been noted (44,45). A possible reason for these differences could be that the enzymes that glycosylate efficiently in vivo have sequences in their luminal domains that lead to the formation of protein complexes and retention of the soluble forms.…”

Section: Discussionmentioning

confidence: 99%

Medial Golgi but Not Late Golgi Glycosyltransferases Exist as High Molecular Weight Complexes

Opat¹,

Houghton

Gleeson

2000

Journal of Biological Chemistry

View full text Add to dashboard Cite

To investigate the organization of Golgi glycosyltransferases and their mechanism of localization, we have compared the properties of a number of medial and late acting Golgi enzymes. The medial Golgi enzymes, Nacetylglucosaminyltransferase I and II (GnTI and Gn-TII) required high salt for solubilization and migrated as high molecular weight complexes on sucrose density gradients. In contrast, the late acting Golgi enzymes, ␤1,4-galactosyltransferase and ␣1,2-fucosyltransferase, were readily solubilized in low salt and migrated as monomers/dimers by sucrose density gradient centrifugation. Analysis of membrane-bound GnTI chimeras indicates that the formation of high molecular weight complexes does not require the transmembrane domain and cytoplasmic tail sequences of GnTI. Furthermore, a soluble form of GnTI, containing the stem region and catalytic domain, accumulated in the Golgi prior to secretion, in contrast to ␤1,4-galactosyltransferase. Soluble GnTI, which also associated with high molecular weight complexes, was comparable with membranebound GnTI in its ability to glycosylate newly synthesized glycoproteins in vivo. Mutation of charged residues within the stem region of GnTI, known to be important for "kin recognition", had no effect on the efficiency of Golgi localization, the inclusion into high molecular weight complexes, nor functional activity in vivo. The differences in behavior between the medial and late acting Golgi enzymes may contribute to their differential localization and their ability to glycosylate efficiently in the correct Golgi subcompartment.

show abstract

“…Detergent solubilization of GalT-I from somatic cells allows the enzyme to bind to a much wider variety of ligands (Begovac et al, 1991). The soluble forms of some glycosyltransferases that are cleaved from the membrane-bound forms glycosylate substrates less efficiently (Zhu et al, 1998). In addition, the binding specificity of GalT-I could be influenced by other proteins in a putative receptor complex in the sperm plasma membrane.…”

Section: ␤14galactosyltransferase As An Adhesion Receptormentioning

confidence: 99%

Molecular Basis of Mammalian Gamete Binding

Miller

Shi

Burkin

2002

Recent Progress in Hormone Research

View full text Add to dashboard Cite

Despite the importance of fertilization for controlling human reproduction, regulating animal production, and promoting preservation of endangered species, the molecular basis underlying gamete binding and fertilization has been perplexing. More progress has been made in the mouse than in other mammals and, recently, targeted deletion of specific genes in the mouse has yielded intriguing results. This review will emphasize research performed by our laboratory and others done primarily with mouse gametes but will include some interesting observations from other mammals. Studies of murine fertilization indicate that oligosaccharides on the egg coat glycoprotein ZP3 bind sperm. The precise oligosaccharides that bind sperm are the subject of considerable debate. ZP3 also induces exocytosis of the sperm acrosome, allowing sperm to penetrate through the egg coat (zona pellucida). A number of candidate ZP3 receptors have been proposed and studies of ␤1,4galacto-syltransferase-I (GalT-I) are reviewed here in the most detail. Sperm from mice with a targeted deletion of GalT-I still are able to bind the zona pellucida but are unable to acrosome react and penetrate through the zona. Therefore, the unique role of GalT-I appears to be in signal transduction. GalT-I forms a complex with heterotrimeric G proteins and activates signaling, leading to exocytosis in sperm and in heterologous cells expressing GalT-I. Other signaling steps triggered by GalT-I are under active investigation; this receptor forms a complex with a protein kinase anchoring protein.After exocytosis of the acrosome, sperm penetrate the zona pellucida and fuse with the oocyte plasma membrane using ADAM family members on sperm and integrins on oocytes. These proteins, along with the tetraspanins on oocytes, may form a complex web at gamete fusion. Targeted deletion of specific genes in this putative complex has provided important information about their redundancy. After the oocyte is fertilized, the binding site for GalT-I is lost from ZP3, preventing additional sperm from binding to the zona pellucida. New technical advances and creative ideas offer the opportunity to make important advances and to solve the conundrum of fertilization.

show abstract

Two soluble glycosyltransferases glycosylate less efficiently in vivo than their membrane bound counterparts

Cited by 29 publications

References 45 publications

Combinatorial Ganglioside Biosynthesis

Combinatorial Ganglioside Biosynthesis

Medial Golgi but Not Late Golgi Glycosyltransferases Exist as High Molecular Weight Complexes

Molecular Basis of Mammalian Gamete Binding

Contact Info

Product

Resources

About