An update on post-translational modifications of hydroxyproline-rich glycoproteins: Towards a model highlighting their contribution to plant cell wall architecture.

HIJAZI, M., M.S. VELASQUEZ, E. JAMET, J.M. ESTEVEZ, CÉCILE ALBENNE

Frontiers in Plant Science

Frontiers

Año: 2014 p. 1 - 10

Plant cell walls are composite structures mainly composed of polysaccharides, also containing a large set of proteins involved in diverse functions such as growth, environmental sensing, signaling, and defense. Research on cell wall proteins (CWPs) is a challenging field since present knowledge of their role into the structure and function of cell walls is very incomplete. Among CWPs, hydroxyproline (Hyp)-rich O-glycoproteins (HRGPs) were classified into three categories: (i) moderately glycosylated extensins (EXTs) able to form covalent scaffolds; (ii) hyperglycosylated arabinogalactan proteins (AGPs); and (iii) Hyp/proline (Pro)-Rich proteins (H/PRPs) that may be non-, weakly- or highly-glycosylated. In this review, we provide a description of the main features of their post-translational modifications (PTMs), biosynthesis, structure and function. We propose a new model integrating HRGPs and their partners in cell walls. Altogether, they could form a continuous glyco-network with non-cellulosic polysaccharides via covalent or non-covalent interactions, thus strongly contributing to cell wall architecture.