Analysis of Occludin Trafficking, Demonstrating Continuous Endocytosis, Degradation, Recycling and Biosynthetic Secretory Trafficking

摘要: Tight junctions (TJs) link adjacent cells and are critical for maintenance of apical-basolateral polarity in epithelial monolayers. The TJ protein occludin functions disparate processes, including wound healing Hepatitis C Virus infection. Little is known about steady-state trafficking into out the plasma membrane. Therefore, we determined mechanisms responsible turnover confluent Madin-Darby canine kidney (MDCK) Using various biotin-based assays observed continuous rapid endocytosis membrane localised (the majority internalised within 30 minutes). By 120 minutes a significant reduction was observed. Inhibition lysosomal function attenuated signal post-endocytosis promoted co-localisation with late endocytic system. similar method demonstrated that ∼20% transported back to cell surface. Consistent these findings, between recycling endosomal compartments We then quantified extent which synthesis transport contributes homeostasis, identifying inhibition led decreased occludin. Significant biosynthetic secretory pathway demonstrated. Thus, under conditions undergoes via cycle endocytosis, degradation, degradation compensated by exocytic trafficking. developed mathematical model describe occludin, utilising experimental data provide quantitative estimates rates processes.