Endosomal GTPases, while often used as markers for specific endosomal organelles, functionalize the surface of endosomal compartments into biochemically distinct subdomains. Their dynamic localization reshapes organelle identities, making it difficult to classify endosomes into rigid categories. In this review, we provide an overview of the functional diversity of endosomal organelles in the context of recent discoveries, highlighting the dynamic role of small GTPases in the organization of cargo trafficking and cargo identity. We suggest that a framework centred on functional subdomains coordinated by ARF and RAB GTPase networks provides an informed perspective on the organisation of endocytic and secretory systems and their crosstalk.
Gershlick et al. (Fri,) studied this question.