Caracterització de la via de senyalització MEK5-ERK5 en cèl·lules neuronals

Nearly all aspects of cell life are controlled by the reversible phosphorylation of proteins. Therefore, our understanding of the molecular control of cell physiology requires the identification of the substrates targeted by specific protein kinases, as well as the identification of interacting proteins that modulate their activities. Mitogen-activated protein kinases (MAP kinases) are signalling proteins that are activated sequentially. MAP kinases represent key signalling molecules through which cells integrate a variety of extracellular stimuli and they regulate many cellular activities such as mitosis, gene expression, metabolism and apoptosis. During the last years, two new members of the MAPK family have been described, namely ERK5 and its activator MEK5. This new signal transduction pathway is activated by growth factors and in response to cellular stress. The MEK5-ERK5 signalling pathway seems to play an important role in neuronal cells, since it is activated in response to neuronal survival factors (neurotrophins) or in response to oxidative stress (involved in the ischemia and reperfusion injury of the brain, as well as in certain neurodegenerative diseases such as Parkinson and Alzheimer). Since it is already known the molecular structure, activation mechanism and the stimuli that activate these kinases, the future lies on the identification of the substrates and the proteins that regulate this pathway. This project will address the following objectives: · Identification and characterization of new ERK5 substrates from neuronal cells. · Identification and characterization of MEK5- and ERK5-interacting proteins. Methodology to be used combines the classical techniques for the study of protein phosphorylation together with the newest technologies for the identification of protein kinase substrates and for the purification of protein complexes under native conditions.