Related Experiment Video
Updated: Jul 15, 2026

OLIgo Mass Profiling (OLIMP) of Extracellular Polysaccharides
Published on: June 20, 2010
Homogalacturonan synthesis in Arabidopsis thaliana requires a Golgi-localized protein with a putative
Grégory Mouille1, Marie-Christine Ralet, Céline Cavelier
1Laboratoire de Biologie Cellulaire, Institut Jean-Pierre Bourgin, INRA, Route de Saint Cyr, 78026 Versailles Cedex, France. gmouille@versailles.inra.fr
Abstract:
Pectins are a family of complex cell-wall polysaccharides, the biosynthesis of which remains poorly understood. We identified dwarf mutants with reduced cell adhesion at a novel locus, QUASIMODO2 (QUA2). qua2-1 showed a 50% reduction in homogalacturonan (HG) content compared with the wild type, without affecting other cell-wall polysaccharides. The remaining HG in qua2-1 showed an unaltered degree of methylesterification. Positional cloning and GFP fusions showed that QUA2, consistent with a role in HG synthesis, encodes a Golgi-localized protein. In contrast to QUA1, another Golgi-localized protein required for HG-synthesis, QUA2 does not show sequence similarity to glycosyltransferases, but instead contains a putative methyltransferase (MT) domain. The Arabidopsis genome encodes 29 QUA2-related proteins. Interestingly, the transcript profiles of QUA1 and QUA2 are correlated and other pairs of QUA1 and QUA2 homologues with correlated transcript profiles can be identified. Together, the results lead to the hypothesis that QUA2 is a pectin MT, and that polymerization and methylation of homogalacturonan are interdependent reactions.
More Related Videos
Related Concept Videos
Oligosaccharide Assembly
Multiple sugar molecules that may or may...
Proteoglycans
Golgi Matrix Proteins
One of the first identified Golgi matrix proteins was GM130, a rod-like protein located in the cis-Golgi. Subsequently, many Golgi...
Role of Microtubules in Cell Wall Deposition
Protein Glycosylation
Glycosylation occurs in...
Protein Transport to the Stroma
Protein complexes called the translocon of the outer chloroplast membrane or TOC complex, and the translocon of the inner chloroplast membrane or TIC complex mediate the...

