Two studies include both Rab4a and Rab11a in their analyses: Go et al. (2021) use BioID to map the proteome in HEK-293 cells (spectral counting-based quantification, two replicates), whereas Liu et al. (2018) combine affinity purification and BioID in a ‘multiple approaches combined’-tagging strategy (HEK-293 and cancer cell lines, spectral counting-based quantification, two replicates), but neither allow for direct quantitative comparison between GTPases. Here, RAB4A is linked to cancer.