Role of Neddylation in neuronal development: phenotypes, targets and future directions

RAQUEL BECERRA; MORGAN SHENG; FERNANDO STEFANI; ANNETTE VOGL; WOLFGANG WURST; IVANA LINENBERG; JAN DEUSSING; SEBASTIAN GIUSTI; NARA I. MURARO; DAMIAN REFOJO

CABA

Congreso; Fronteras en Biociencia 3; 2018

IBioBA-CONICET-MPSP y la Max Planck Society de Alemania

Ubiquitin-like proteins (UBLs) represent a family of polypeptides characterized by their high homology with Ubiquitin and ability to bind to their target-proteins in a covalent and reversible fashion by an isopeptide bond to lysine amino acids. Even though Ubiquitin role is well established, the role of other UBLs, except SUMO, have not been yet broadly explored. Nedd8 is the UBL with the highest homology with Ubiquitin. The Cullins are the best-characterized substrates of the Nedd8 pathway. They are the main scaffolds of the SCF (Skp1/cullin/F-box) ubiquitin ligase complex, which control ubiquitylation and proteasomal degradation of proteins mainly involved in cell cycle control and cellular proliferation. In recent studies, our lab has demonstrated that Nedd8 is a critical factor for synapse development and stability and that these effects are Cullin-independent. However, Nedd8?s role as a true post-translational modification has been recently challenged under the argument that conclusive data supporting neddylation of non-Cullin targets is missing so far. This controversy is what this project will, in part, contribute to solve. To do this, and employing a new mass spectrometry-based approach, we have generated a complete atlas of neddylated proteins in a broadly used and accepted cellular model: HEK cells. In a second screening in primary cortical culture, we have identified potential neddylation targets in neurons. Furthermore, we have recently generated a transgenic mouse line specially designed to allow the biochemical detection of Nedd8 targets and their specific neddylated lysine residues and we will use it to identify the neddylome present in various tissues.Now it is necessary to start with a thorough process of biochemical and functional validation of selected Nedd8 target candidates focusing on their potential role in neuronal development and function. In this context, we are systematically analyzing the genes and, after selecting and validating them, we intend to investigate the functional role of neddylation in selected targets by generating transgenic flies, in which these genes are replaced by a non-neddylable isoform.