(d) HeLa cells were transfected with AMBRA1 RNAi oligonucleotide (siRNA AMBRA1). Then, cells were co-transfected with vectors encoding ubiquitin-HA and AMBRA1WT or AMBRA1AA, respectively. Protein extracts were immunoprecipitated using anti-ULK1 antibody; ubiquitin-HA, ULK1 and AMBRA1 were analysed by western blotting. 