FUNCTIONAL CHARACTERIZATION OF A NOVEL PUTATIVE GTPase ACTIVATING PROTEING (GAP) INVOLVED IN HUMAN EPILEPSY

We have recently identified the gene responsible for a familial form of epilepsy. The main goal of the project is to determine the biological role of this gene and to clarify the epileptogenic pathways of mutations. We will initially determine which tissues and organs express the novel protein and where the protein is located within the cell. We will then try to identify proteins of known function, specifically interacting with our protein in order to define a possible molecular pathway in which the protein is involved. On the basis of aminoacid sequence similarity with proteins (GAPs) that activate small GTPases (Rabs) regulating vescicular transport and membrane trafficking, we hypothesized that the novel protein might also interact with some Rab protein. Hence, we will first determine if interactions occur with members of Rab family implicated in neuronal functions. Moreover we will search for additional interacting proteins by a new technology, combining Laser Ionization and Mass Spectrometry (SELDI-TOF-MS). On the basis of previous experiments we will explore the role of the novel protein in specific processes by selectively overexpressing and silencing the protein. Finally, the molecular and cellular dysfunction associated to epileptogenic mutations will be also investigated by comparing the behaviour of wt and mutant proteins at each stage of the project. The present proposal will shed light into molecular pathways regulating neuronal and brain functions and open novel insights into biological events leading to neuronal hyperexcitability and seizures. In addition, the characterization of novel proteins involved in epilepsy will also provide a novel biological target for the development of antiepileptic drugs.