Determining the molecular mechanisms of extracellular vesicle budding

• Applicant: Professor Dr. José Pedro Friedmann Angeli, since 3/2020
• Subject Area: Cell Biology ; Developmental Biology
• Term: from 2017 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 378148210

Cells release extracellular vesicles that can act as signaling platforms during development and in numerous diseases. Many extracellular vesicles form by budding outward from the plasma membrane, but the mechanisms were previously unknown. In previous studies, I established a unique genetic model system to define the mechanisms of extracellular vesicle budding. I discovered that loss of the conserved lipid flippase TAT-5 causes increased budding of extracellular vesicles in C. elegans embryos. Using this system, I found that regulators of viral budding are also required for extracellular vesicle budding, demonstrating that budding occurs via conserved mechanisms hijacked by viruses. This work established the first system to study extracellular vesicles in vivo. The goals of this proposal are to determine how proteins regulate extracellular vesicle budding. These aims are an essential first step to defining the signaling roles of extracellular vesicles, which have primarily been demonstrated with purified vesicles. In Aim 1, we identify new proteins that regulate extracellular vesicle budding and assemble them into a molecular pathway with TAT-5, expanding our understanding of how membrane dynamics are regulated. In Aim 2, we determine how the proteins PAD-1 and MON-2 regulate TAT-5 activity to control extracellular vesicle formation. In Aim 3, we test the hypothesis that TAT-5 is trafficked by the retromer recycling pathway and determine whether TAT-5 functions in retromer trafficking. This aim would link TAT-5 to a new cellular function. In summary, the proposed research will reveal how the dynamic budding of extracellular vesicles is regulated in the genetic model organism C. elegans. These aims form the basis for future experiments where we will define the functional role of extracellular vesicles, which would provide the first in vivo evidence for extracellular vesicle signaling. This proposal forms the groundwork for studies determining the mechanisms of extracellular vesicle budding in mammalian cells during development and disease. Because viruses co-opt extracellular vesicle budding mechanisms, this study may also reveal new antiviral targets and thereby impact human health. Thus, the proposed work has the potential to impact many fields ranging from membrane biophysics to developmental biology to disease modeling.

• DFG Programme: Research Grants
• Ehemalige Antragstellerin: Dr. Ann Wehman, until 2/2020