A multidisciplinary approach to unravel the novel role of Rab proteins in cell migration

Cell migration is a very complex process that has a fundamental role in different physiological situations (e.g. development, immune response, repair of injured tissues), and in pathological conditions such as cancer or immune disorders. It is therefore important to understand in detail the entire components and mechanisms regulating this sophisticate process. Based on our results that indicate the involvement of a family of proteins, the Rabs, in the process of cell migration, the main objective of this project was to identify and characterize novel members of this family of proteins and their interaction partners involved in the process of cell migration. By using a multidisciplinary approach which combines cell and molecular biology, proteomics, biophysics and biochemistry, we aimed to unravel the structure-function relationship of the identified proteins, cell dynamics and mechanical properties that they regulate, and their functional implications at organism level. In this project, we identified and characterized new Rab proteins involved in the process of cell migration, as well as their interactors, in order to further understand how they regulate cell migration. In this way, we have revealed different molecular mechanisms used by Rab proteins to modulate cytoskeleton dynamics and formation of cellular protrusions required for proper cell motility. We have also validated the functional relevance of our findings in in vivo systems using zebrafish and mice models. In sum, this approach allowed us to entirely characterize novel pathways involved in cell migration from molecular to organism level. Since cell migration is a fundamental process also for many pathological situations, the results achieved in this project can provide important and entirely new information not only for a basic understanding of cell biology, but also for further applications in designing therapies to counter diseases.

The results obtained in this project contribute to scientific innovation and development of new knowledge by providing new insights into the fields of intracellular trafficking and cell migration, all basic processes with strong implication in physiological and pathological conditions like immunity and cancer. By combining cell biology, proteomics, biochemistry and biophysics, and involving collaboration with several international and Norwegian laboratories, this project has contributed to increase interdisciplinary and international research collaboration. Furthermore, the discovery of a key involvement of Rab proteins in cell migration, a key process also for pathologic conditions such as inflammation and cancer, may have further potential application in the development of new therapies to fight these diseases (e.g. development of new targeted cell migration inhibitors for anti-inflammatory or anti-cancer therapies).

Rab proteins are small GTPases, master regulators of the intracellular trafficking. In their active form, they associate with downstream effectors such as tethering factors, motor proteins, kinases, and phosphatases. The interaction between Rabs and cytoskeletal proteins was believed to only regulate intracellular transport. However, we have recently found that it is also central for the regulation of cell migration. The objective of our project is therefore to identify Rabs that regulate cell migration, their interactors, and the underlying molecular mechanisms, using an innovative multidisciplinary approach that relies on state-of-the-art technologies. In particular, we will perform microscopy and proteomic screenings to identify Rab proteins and their interactors regulating cell migration. Subsequently, we will characterize the structure/function relationship of the identified complexes by molecular dynamics simulations in combination with 5D-imaging. We will also study how the identified Rabs and their interactors regulates the physical properties in migrating cells. Finally, we will study the functional relevance of the identified proteins in animal models. Cell migration is a fundamental process regulating physiological and pathological situation (such as inflammation and cancer). Therefore, the results achieved will provide important and entirely new information not only for a basic understanding of cell biology, but also for further applications in designing therapies to counter diseases. Indeed, the identification of novel regulators of cell migration can open new possibilities for the development of targeted inhibitors with potential use in anti-inflammatory or anti-cancer therapies.