fig5

Figure 5. Pathways governing the secretion of exosomes from MVBs. MVBs can either fuse with the plasma membrane, resulting in the release of ILV as exosomes into the extracellular environment, or fuse with lysosomes for cargo degradation. The exosomal secretion pathway is facilitated by interactions that involve PSEN1, RAB27A, RAB31, and SUMOylated adapter protein SKP1, which promote vesicle trafficking to the plasma membrane. Conversely, lysosomal degradation is controlled by RAB7, RAB2A, and phosphorylated SKP1. The mechanism of microvesicle secretion remains poorly understood. Created in BioRender. Ju, J. (2025) https://BioRender.com/wcsvh0m. MVBs: Multivesicular bodies; ILVs: intraluminal vesicles; PSEN1: presenilin 1; SKP1: S-phase kinase-associated protein 1.