fig3

Figure 3. S1P receptor activation in ILV cargo sorting. During the maturation of MVBs, sphingolipids are hydrolyzed into ceramide and S1P. Activation of the S1P receptor on MVBs results in the dissociation of the G_βγ subunit from the G_i subunit and stimulates interaction with PLEKHG2 and P-Rex1. The subsequent activation of components of the Rho family GTPases (CDC42 and RAC1) results in F-actin alignment. F-actin is required for cargo sorting into exosomes through its adaptor protein function. Created in BioRender. Ju, J. (2025) https://BioRender.com/vhrj9op. S1P: Sphingosine 1-phosphotase; ILVs: intraluminal vesicles; MVBs: multivesicular bodies; RAC1: Ras-related C3 botulinum toxin substrate 1; EXO: a common short sequence motif enriched in miRNA; AP-2: adaptor-related protein complex 2; YBX1: Y-box protein I; CDC42: cell division control protein 42 homolog; SphK2: sphingosine kinase 2.