Recent Advances on the Posttranslational Modifications of EXTs and Their Roles in Plant Cell Walls.
The genetic set up and the enzymes that define the O-glycosylation sites and transfer the activated sugars to cell wall glycoprotein Extensins (EXTs) have remained unknown for a long time. We are now beginning to see the emerging components of the molecular machinery that assembles these complex O-glycoproteins on the plant cell wall. Genes conferring the posttranslational modifications, i.e., proline hydroxylation and subsequent O-glycosylation, of the EXTs have been recently identified. In this review we summarize the enzymes that define the O-glycosylation sites on the O-glycoproteins, i.e., the prolyl 4-hydroxylases (P4Hs), the glycosyltransferases that transfer arabinose units (named arabinosyltransferases, AraTs), and the one responsible for transferring a single galactose (galactosyltransferase, GalT) on the protein EXT backbones. We discuss the effects of posttranslational modifications on the structure and function of extensins in plant cell walls.
Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIByNE-CONICET), Universidad de Buenos Aires Buenos Aires, Argentina.
Melina
M
Velasquez
Juan Salgado
JS
Salter
Javier Gloazzo
JG
Dorosz
Bent L
BL
Petersen
José M
JM
Estevez