Year: 2022
Type: dissertation
Abstract: Membrane traffic is an essential process to regulate the functions and survival of cells by allowing the transport of various cargo to their target compartments. As a result, the regulation of this traffic is very important, and when defects occur, different diseases can be associated with it. Therefore, several classes of proteins are responsible for maintaining this balance. Notably, one of the crucial families is the RAB GTPases. These RABs are controlled by Guanine Exchange Factors (GEFs) that enable their activation. This activation allows RABs to interact with their effectors to mediate their functions. GTPases Activating Proteins (GAPs) are responsible for activating the intrinsic activity of GTPase to hydrolyze GTP into GDP, thus inactivating them once their functions have been performed. Identifying these positive and negative regulators is essential to better understand the various functions of RABs in vesicular transport. The research conducted in this thesis attempted to define new regulatory or effector proteins for RAB25. To identify these regulators and effectors, the proximity ligation technique mediated by the APEX2 fusion protein coupled with mass spectrometry was used. Using these proteomics data, it was possible to observe that the GTPase RAB25 was associated with many enriched interactors, such as the proteins ALS2, TBC1D8B and DENND6A. Thus, interaction and/or proximity tests were carried out with the proteins ALS2, TBC1D8B and more particularly DENND6A. In addition, functional assays were performed to validate the effects of the GEF DENND6A on RAB25 functions in migration and invasion in MCF-7 and/or MDA-MB- 231 cancer cells. These tests seem to show that the loss of DENND6A in the presence of RAB25 induces an increase in migration and cell invasion. This work identified novel RAB25 interactors with potential functions in cell migration and invasion.
Author: Larcher, Raphaëlle
Language: French
Subfield: Cell Biology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7201927016