Abstract:

Structural proteins are important compositions in plant cell wall, and the first structural protein detected in plant cell wall is one of extensins which account for 1%-15% of the dry weight of the primary cell wall.The term extensin generally refers to all hydroxyproline-rich glycoprotein members in an inclusive sense. However, the term is also used to specifically describe HRGPs possessing Ser-Hyp₄ repeat motif. Their major functions are to control cell wall extension, and to enhance the mechanical resistance of plant cell wall. In recent years, studies on rsh mutant of Arabidopsis demonstrated that extensins also played an essential role in initiating the cell wall formation, which was a nascent function of extensins. The post-translational modifications of extensins include proline hydroxylation and the subsequent glycosylation of Hyp and Ser residues, intra- and inter-molecular cross-links activated by peroxidase, self-assembly through linear and lateral molecule links. Since extensins are one of the main structural proteins in plant cell wall, studying the function and structure of extensins is important for our better understanding about cell wall structure and cell wall assembly.

Key words: extensin, cross-link, glycosylation