Based on studies in mice, FOXO1 and possibly FOXO3 directly stimulate transcription of the KLF4 gene, encoding a transcription factor Krueppel-like factor 4. KLF4 inhibits proliferation of mouse B cells (Yusuf et al. 2008). KLF4 has been reported to transcriptionally repress FOXO1 gene (Tang et al. 2016). In hypothalamic orexigenic neurons, KLF4 positively regulates expression of AGRP (agouti-related protein), an established FOXO target (Imbernon et al. 2014).