I selected several ubiquitin ligases involved in cellular growth and survival and affinity-purified their complexes. Systematic analysis and biochemical approaches led to the discovery of new substrates of these ligases and description of signaling pathways involved in these regulations. These results led us to conclusions and hypotheses describing the physiologic roles of these proteins. To confirm the physiological role of these ligases we prepared cellular and mouse models of their deficiencies and characterize their role in the complex context of cell or organism. Results obtained from the LIGER project were already presented in the CSHL - prestigious conference focused on the proteasome-ubiquitin system, where they were selected for oral and poster presentations. Besides the scientific community, this project has been presented to professionals active in scientific communication and museum exhibitions at ECSITE (15-17 June 2017, Porto) and at the 100.000th MSCA Fellow Awards Ceremony (27 September 2017, Brussels) with the attendance of Tibor Navracsics, Commissioner for Education, Culture, Youth and Sport.