Fig. 10

Proposed model for the potential role of ATGLCAT14A and ATGLCAT14C in Arabidopsis mucilage secretory cells during mucilage formation. This proposed model was based on previous studies [12, 42, 45, 56]. In a, the interaction of glucuronidated AG glycan and Ca²⁺ may stabilize the interaction between AGPs (e.g., SOS5) and FEI receptor kinases leading to the activation of the FEI kinase domain. FEI1/FE2 binding to ACC synthase (ACS5/9) limits the production of ACC, and influences either directly or indirectly, the formation of cellulose microfibril assembly, independent of ethylene [45]. In b, the absence or reduction of glucuronidated AG glycans may interfere with and reduce Ca²⁺ binding [12, 40] and may destabilize the activities of FEI receptor like proteins by altering potential interactions between AGPs and FEI. ACC synthase remains unbound to FEI proteins and becomes freely available for the increased production of ACC, which inhibits cellulose synthesis and increases the production of ethylene [42]. Similarly, hypoglycosylated moieties characterized by AG glycan modifications are targeted for destruction to the vacuoles via multivesicular bodies [56]