Project Details
Projekt
Elucidation of the molecular mechanisms regulating the deubiquitylase AMSH and its targets (C08)
Subject Area
Biochemistry
Term
from 2018 to 2023
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 189682160
Selective protein degradation is one of the key processes that regulate proteostasis in eukaryotic cells. To optimize growth and development according to diverse external factors and react to various stresses, the abundance of plasma membrane receptors and transporters has to be precisely regulated. Besides transcriptional regulation, ubiquitin-mediated endosomal degradation plays a key role in this process. The ESCRTs (Endosomal Sorting Complexes Required for Transport) comprise the core endocytic machinery that guide the ubiquitylated membrane protein from the plasma membrane to the vacuoles or lysosomes for degradation. ESCRTs contain ubiquitin-binding subunits but interact also with other ubiquitin adaptors and DUBs (deubiquitylating enzymes) such as AMSH (Associated Molecule with the SH3-domain of STAM) that are important for the coordination of cargo trafficking. Intensive structural, biochemical and genetic studies in the past decade on core ESCRT components have elucidated various molecular details. In contrast, functions of ESCRT-interacting proteins and the molecular mechanisms by which they affect ESCRT-function and endocytic degradation is yet mostly unknown. In this project, we focus on the ESCRT-associated DUB AMSH and the AMSH-interacting ubiquitin adopter protein ALIX (ALG2-interacting protein X). Though both proteins are essential in higher eukaryotes, the mechanisms by which AMSH and ALIX are regulated has not yet been understood. Thus, we aim to elucidate the molecular mechanisms by which ALIX and ALIX-interacting proteins recruit AMSH to endosomal membranes and how this is coordinated during endosomal transport and degradation. Although many ubiquitin-proteomes have been published in recent years, specific targets of AMSH have been so far only identified in targeted analyses. Another goal of this project is therefore to identify targets of AMSH by proteomic analysis. By verifying the proteins that are enriched in either in the wild type or in the amsh mutant, we aim to identify AMSH targets and investigate whether and how AMSH regulates cargo stability.
DFG Programme
Collaborative Research Centres
Applicant Institution
Universität Konstanz
Project Head
Professorin Dr. Erika Isono
