Project description
Molecular insight into the dynamics of the actin cytoskeleton
Cell shape and movement are primarily driven by the actin cytoskeleton, a dynamic network of actin filaments. Mutations in actin impair cell integrity and function and may lead to disease. The scope of the EU-funded MolecularArp project is to delve into the role of the Arp2/3 protein complex, which is responsible for the branching of actin filaments. Researchers will investigate the individual properties of the different Arp2/3 complexes and delineate their impact on the structure and function of the actin cytoskeleton as well as on cell migration. Overall, the project will provide important insight into the dynamics of the cell cytoskeleton and the diversity of its molecular determinants.
Objective
The actin cytoskeleton is a dynamic polymer system, that provides the driving force and structural support for the physical integrity of cells, and their interactions. It also regulates many essential cellular processes, such as membrane trafficking and cell migration. Not surprisingly, its malfunction results in a wide variety of syndromes and diseases. Branched actin networks can only be assembled by the Arp2/3 complex, consisting of seven protein subunits. Activated by nucleation promoting factors (NPFs), Arp2/3 binds to the side of an actin filament to initiate an actin branch and new filament growth. Arp2/3 has been regarded as a single entity, but in mammals, three of its subunits exist as two isoforms, thus allowing the formation of 8 different complexes. Recent work demonstrates that the 8 human Arp2/3 complexes have unique cellular properties. However, it is unclear why these complexes are so different and whether they have distinct cellular functions. Using in vitro biochemical assays and single molecule analysis together with sophisticated cell biology approaches, I will determine the molecular basis for the individual properties of the different Arp2/3 complexes. Observing in vitro reconstituted actin networks, I will perform a detailed analysis of the actin nucleation properties of the 8 Arp2/3 complexes and the impact of different NPFs. In addition, I will also analyse actin branch disassembly to uncover the molecular basis of actin debranching, which still remains to be established. To investigate the cellular function of individual Arp2/3 family members, I will generate genome edited cells expressing defined Arp2/3 complexes and examine their lamellipodial actin dynamics and cell migration. Moreover, by generating Arp2/3 complex specific biosensors, I will map the cellular distribution of individual Arp2/3 complexes. My combined approaches will allow me to understand the molecular and cellular basis of Arp2/3 diversity in humans.
Fields of science
Programme(s)
Funding Scheme
MSCA-IF - Marie Skłodowska-Curie Individual Fellowships (IF)Coordinator
NW1 1AT London
United Kingdom