Showing papers by "Debra Mohnen published in 2011"
TL;DR: This study provides conclusive evidence that the GAUT1:GAUT7 complex is the catalytic core of an HG:GalAT complex and that cell wall matrix polysaccharide biosynthesis occurs via protein complexes.
Abstract: Plant cell wall pectic polysaccharides are arguably the most complex carbohydrates in nature. Progress in understanding pectin synthesis has been slow due to its complex structure and difficulties in purifying and expressing the low-abundance, Golgi membrane-bound pectin biosynthetic enzymes. Arabidopsis galacturonosyltransferase (GAUT) 1 is an α-1,4-galacturonosyltransferase (GalAT) that synthesizes homogalacturonan (HG), the most abundant pectic polysaccharide. We now show that GAUT1 functions in a protein complex with the homologous GAUT7. Surprisingly, although both GAUT1 and GAUT7 are type II membrane proteins with single N-terminal transmembrane-spanning domains, the N-terminal region of GAUT1, including the transmembrane domain, is cleaved in vivo. This raises the question of how the processed GAUT1 is retained in the Golgi, the site of HG biosynthesis. We show that the anchoring of GAUT1 in the Golgi requires association with GAUT7 to form the GAUT1:GAUT7 complex. Proteomics analyses also identified 12 additional proteins that immunoprecipitate with the GAUT1:GAUT7 complex. This study provides conclusive evidence that the GAUT1:GAUT7 complex is the catalytic core of an HG:GalAT complex and that cell wall matrix polysaccharide biosynthesis occurs via protein complexes. The processing of GAUT1 to remove its N-terminal transmembrane domain and its anchoring in the Golgi by association with GAUT7 provides an example of how specific catalytic domains of plant cell wall biosynthetic glycosyltransferases could be assembled into protein complexes to enable the synthesis of the complex and developmentally and environmentally plastic plant cell wall.
196 citations
TL;DR: A specific type of O-glycosylation is explored for plant cell wall structural proteins and this modification to root hair growth is connected to cell recognition processes.
Abstract: The two most abundant natural organic polymers on Earth are cellulose and chitin, characterized by long chains of carbohydrates that bear a specific type of sugar linkage called O-glycosylation. This type of linkage also occurs between polysaccharides (glycans) and proteins and glycans and lipids, yielding glycoconjugates that are well known to function in cell recognition processes ( 1 ). On page 1401 in this issue, Velasquez et al. ( 2 ) explore a specific type of O-glycosylation for plant cell wall structural proteins and connect this modification to root hair growth.
8 citations
Patent•
15 Apr 2011TL;DR: In this article, plants having altered expression of a GAUT polypeptide have been identified as having phenotypes that may include decreased recalcitrance, increased growth, decreased lignin content, or a combination thereof.
Abstract: Provided herein are plants having altered expression of a GAUT polypeptide. Such plants have phenotypes that may include decreased recalcitrance, increased growth, decreased lignin content, or a combination thereof. Also provided herein are methods of making and using such plants.
4 citations
Patent•
15 Apr 2011
TL;DR: In this article, an invention concerne des plantes don't express l'expression d'un polypeptide GAUT est modifiee, and concernes egalement des methodes de fabrication and d'utilisation of ces plantes.
Abstract: Cette invention concerne des plantes dont l'expression d'un polypeptide GAUT est modifiee. Les phenotypes de ces plantes peuvent inclure une reduction de l'etat de dormance, une augmentation de la croissance, une baisse de la teneur en lignine, ou une association de ces proprietes. L'invention concerne egalement des methodes de fabrication et d'utilisation de ces plantes.