Effect of NAP1L1 silencing. Effect of NAP1L1 silencing on p57Kip2 and menin expression as well as on the mTOR pathway in BON cells. An effective NAP1L1 knockdown (approximately 3-fold, *p < 0.001) increased p57Kip2 protein (A) and mRNA (B) (#p < 0.01), while menin was increased at protein level only (A and B). The ERK pathway was unaffected in NAP1L1-silenced cells, while total mTOR as well as phosphorylated mTOR decreased in NAP1L1 silenced BON cells (C). The mTOR downstream effectors eukaryotic initiation factor 4E-binding protein (4E-BP1) and S6 kinase (S6K1) also showed less protein expression and decreased phosphorylation when NAP1L1 was absent (D and E) (*p < 0.05). MRNA levels of the two ribosomal proteins RPS24 and RPL28, as a measure of mTOR activity, were also decreased in NAP1L1 knockdown cells (*p < 0.05), indicating that NAP1L1 may promote mTOR signaling (F). 4E-BP1, lower band. Mean ± standard error of mean (SEM).