NEDD4 co-expression enhances the transcriptional activity of KLF8 in the pS48 dependent manner. luciferase activity in NIH3T3 cells co-transfected with the plasmid vectors encoding wild type (WT) KLF8, its mutants (S48A or S48D) or nothing (vector), alone or together with NEDD4 expressing vector, along with the cyclin D1 promoter luciferase reporter plasmid [9,44]. The reporter activity was performed as described in the Materials and Methods section [44]. *P<0.05, **P<0.01, ***P<0.005.