Positions 5, 8 and 9 within the Nβ motif differ between secretory and cytosolic proteins.

(A) Distribution of the protein sequences among the categories generated based on the UniProtKB database regarding cellular localisation: A category (2.63%); B category (25.66%); C category (2.63%); D category (69.08%). (B) Logos of the sequences found in A category (upper) and C category proteins (down). (C) Transient expression assays in onion epidermal cells (as in Fig 2) of the different Nβ variants fused to GFP. Cyt: cytoplasm; CW: cell wall. Scale bar: 50 μm.