Luciferase assay
Cells were lysed with Luciferase Cell Culture Lysis Reagent (Promega); after protein concentration determination (Bradford assay) luciferase quantification was assessed in luciferase assay buffer (470 μM luciferin, 20mM Tricine, 0.1 Mm EDTA, 1.07 Mm (MgCO3)4·Mg(OH)2×5H2O; 2.67 mM MgSO4×7H2O in H2O, pH 7.8, with 33.3 mM DTT and 530 μM ATP), by measuring luminescence emission with a Veritas luminometer (Promega). The relative luminescence units (RLU), determined during a measurement of 10 s time and expressed as luciferase units/μg protein, were calculated as compared with blank control samples.