Involved in the formation of X-, Y-shaped and twinned plasmodesmata (PD), thus modelating PD size exclusion limit and regulating cell-to-cell transport (PubMed:22411811). Cell cycle checkpoint regulator that monitors and responds to DNA damage such as DNA cross-links, and triggers the halt of the cell cycle progression in the presence of DNA cross-linking agents. Mediates the active process of aluminum- (Al) dependent root growth inhibition and thus is required for response to Al toxicity (PubMed:22345493). Required for both early and late phases of embryo development as well as during seedling growth (PubMed:16113228, PubMed:15266054). Essential for signal transduction and development of both male and female organs (PubMed:22411811).