Biogenesis and trafficking of EGFR-enriched extracellular vesicles

Abstract

Extracellular vesicles (EVs) are crucial for intercellular communication and material exchange. Epidermal Growth Factor Receptor (EGFR) is a vital single transmembrane signaling receptor, yet the specific mechanisms underlying the formation of EGFR-enriched EVs remain unclear. In this study, we employed a method to isolate EGFR-enriched EVs and discovered that both EGFR and its mutant EGFR (L858R) exhibit reversed orientation on the EV membrane compared to the cell membrane. Additionally, single-pass transmembrane proteins such as Integrin β3 and VTI1B also showed inverted orientation, while the four-pass transmembrane protein CD9 maintained its normal orientation. This suggests a propensity for orientation inversion in single-pass proteins during EV formation. We also found that the generation of EGFR-enriched EVs is independent of ESCRT-mediated exosome pathways, as disrupting VPS4 function did not affect the production of EGFR and its mutant EGFR (L858R) in EVs. However, this process is influenced by post-Golgi transport mechanisms, as knocking out AP-1, which is responsible for the post-Golgi transport of EGFR, significantly reduced the production of EGFR-enriched EVs. Furthermore, the content of EGFR (L858R) in EVs was lower compared to EGFR, and low concentrations of EGF stimulation led to a decrease in EGFR-enriched EV content, indicating that EGFR activation affects the production of these EVs. These findings provide new insights into the unique mechanisms governing the formation and regulation of EGFR-enriched EVs.

Date of Award	2024
Original language	English
Awarding Institution	The Hong Kong University of Science and Technology
Supervisor	Yusong GUO (Supervisor)