title: The inside and outside: topological issues in plant cell wall biosynthesis and the roles of nucleotide sugar transporters.
abstract: The cell wall is a complex extracellular matrix composed primarily of polysaccharides. Noncellulosic polysaccharides, glycoproteins and proteoglycans are synthesized in the Golgi apparatus by glycosyltransferases (GTs), which use nucleotide sugars as donors to glycosylate nascent glycan and glycoprotein acceptors that are subsequently exported to the extracellular space. Many nucleotide sugars are synthesized in the cytosol, leading to a topological issue because the active sites of most GTs are located in the Golgi lumen. Nucleotide sugar transporters (NSTs) overcome this problem by translocating nucleoside diphosphate sugars from the cytosol into the lumen of the organelle. The structures of the cell wall components synthesized in the Golgi are diverse and complex; therefore, transporter activities are necessary so that the nucleotide sugars can provide substrates for the GTs. In this review, we describe the topology of reactions involved in polysaccharide biosynthesis in the Golgi and focus on the roles of NSTs as well as their impacts on cell wall structure when they are altered.
authors: Centro de Biotecnología Vegetal, FONDAP Center for Genome Regulation, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Avenida República 217, Santiago, RM 837-0146, Chile.
authors: Henry
authors: H
authors: Temple
authors: Centro de Biotecnología Vegetal, FONDAP Center for Genome Regulation, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Avenida República 217, Santiago, RM 837-0146, Chile.
authors: Susana
authors: S
authors: Saez-Aguayo
authors: Centro de Biotecnología Vegetal, FONDAP Center for Genome Regulation, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Avenida República 217, Santiago, RM 837-0146, Chile.
authors: Francisca C
authors: FC
authors: Reyes
authors: Centro de Biotecnología Vegetal, FONDAP Center for Genome Regulation, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Avenida República 217, Santiago, RM 837-0146, Chile aorellana@unab.cl.
authors: Ariel
authors: A
authors: Orellana
mesh_terms: D001692:Biological Transport / Q000235:genetics; D002473:Cell Wall / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D006031:Glycosylation; D006056:Golgi Apparatus / Q000235:genetics / Q000378:metabolism; D009004:Monosaccharide Transport Proteins; D009711:Nucleotides / Q000737:chemistry / Q000378:metabolism; D059828:Plant Cells / Q000378:metabolism*; D011134:Polysaccharides / Q000096:biosynthesis* / Q000235:genetics; D000073893:Sugars / Q000378:metabolism*
chemical_list: D009004:Monosaccharide Transport Proteins; D009711:Nucleotides; D011134:Polysaccharides; D000073893:Sugars
keywords: cell wall biosynthesis, glycosyltransferases, Golgi, nucleotide sugar transporters, polysaccharides