N ‐linked glycosylation of At VSR 1 is important for vacuolar protein sorting in A rabidopsis

Summary Vacuolar sorting receptors ( VSR s) in Arabidopsis mediate the sorting of soluble proteins to vacuoles in the secretory pathway. The VSR s are post‐translationally modified by the attachment of N ‐glycans, but the functional significance of such a modification remains unknown. Here we have studied the role(s) of glycosylation in the stability, trafficking and vacuolar protein transport of At VSR 1 in Arabidopsis protoplasts. At VSR 1 harbors three complex‐type N ‐glycans, which are located in the N‐terminal ‘ PA domain’, the central region and the C‐terminal epidermal growth factor repeat domain, respectively. We have demonstrated that: (i) the N ‐glycans do not affect the targeting of At VSR 1 to pre‐vacuolar compartments ( PVC s) and its vacuolar degradation; and (ii) N ‐glycosylation alters the binding affinity of At VSR 1 to cargo proteins and affects the transport of cargo into the vacuole. Hence, N ‐glycosylation of At VSR 1 plays a critical role in its function as a VSR in plants.