Fig. 1: Proximity proteomics of endosomal sorting sub-domains.

A Schematic representation of proximity-dependent biotin identification (BioID) of a protein of interest (POI) over the endosomal surface. B Cartoon depicting endosomal proteins tagged with BioID1, including a soluble version called cytosolic BioID1 and a TOM70-directed cytoplasmic facing mitochondrial external membrane. C Single experiment western blot showing comparison of total protein levels of the BioID1-tagged proteins expressed in the engineered cell lines using an antibody against the FLAG epitope. D Single experiment western blot comparing biotinylated proteins after 24 h biotin incubation, lysis and streptavidin purification among the different cell lines. E–H Volcano plots representing the proteins detected in proximity to the indicated endosomal proteins when compared with the cytosolic BioID1. n = 6 independent experiments, standard two-sided t-test analysis. X-axis denotes Fold Change (FC) in Log₂ scale and Y-axis statistical significance in -Log₁₀ scale format; for reference, 1.3 -Log₁₀ is equal to 0.05 p-value. The right insets are magnifications showing only significant proteins (\(\ge\)1.3) with FC \(\ge\) 0.8. In magenta, already known interactors, in blue, transmembrane proteins, in green, unrecognised or barely studied interactors. E BioID1-VPS35. F VPS35-BioID1. G BioID1-SNX27. H BioID1-HRS/HGS.