Hiroshi Yamamoto, Fatma Ozturk, Camila Alvarez
Membrane trafficking is a fundamental process in cell biology that ensures proper distribution and function of cellular components. This study investigates the role of Rab GTPases in regulating endosomal membrane trafficking dynamics. Our objective was to delineate the specific contributions of Rab5 and Rab7 in the early and late endosomal stages, respectively. Using live-cell imaging and quantitative fluorescence microscopy, we tracked the motion and interaction of these GTPases in HeLa cells. Our findings reveal that Rab5 is crucial for the initial endocytic vesicle formation and early endosome fusion, with a significant increase in co-localization observed (p < 0.01). Conversely, Rab7 was found to facilitate the transition from early to late endosomes, enhancing cargo sorting efficiency (p < 0.05). These insights were further supported by gene knockdown studies, which demonstrated impaired trafficking and increased endosomal retention upon Rab7 depletion. Our study underscores the distinct but complementary roles of Rab5 and Rab7 in endosomal trafficking, highlighting their potential as therapeutic targets in diseases linked to trafficking dysregulation. These findings contribute to a deeper understanding of membrane trafficking mechanisms and open avenues for targeted cellular interventions.