Transcription factor that forms a trimeric complex with POU5F1 (OCT3/4) on DNA and controls the expression of a number of genes involved in embryonic development such as YES1, FGF4, UTF1 and ZFP206 (PubMed:15863505, PubMed:17097055, PubMed:19740739). Binds to the proximal enhancer region of NANOG (PubMed:15863505). Critical for early embryogenesis and for embryonic stem cell pluripotency (By similarity). Downstream SRRT target that mediates the promotion of neural stem cell self-renewal (PubMed:22198669). Keeps neural cells undifferentiated by counteracting the activity of proneural proteins and suppresses neuronal differentiation (By similarity). May function as a switch in neuronal development (By similarity). Interacts with ZSCAN10 (PubMed:19740739). Interacts with SOX3 and FGFR1 (PubMed:17728342). Interacts with GLIS1 (By similarity). Interacts with POU5F1; binds synergistically with POU5F1 to DNA (PubMed:15863505). Nuclear import is facilitated by XPO4, a protein that usually acts as a nuclear export signal receptor. Expressed in the cochlea (at protein level) (PubMed:32127020). Expressed in the brain and retina (PubMed:7590241, PubMed:15863505). A very low level of expression is seen in the stomach and lung (PubMed:7590241, PubMed:15863505). Expressed in the kidney (PubMed:15863505). Expressed in the basal cells of the tongue epithelium at birth until P20 (PubMed:32758484). Expressed in the suprabasal cells of the buccal mucosa and esophagus at P20 (PubMed:32758484). By SRRT. The 9aaTAD motif is a transactivation domain present in a large number of yeast and animal transcription factors. Sumoylation inhibits binding on DNA and negatively regulates the FGF4 transactivation. Embryonically lethal. POU5F1/OCT4, SOX2, MYC/c-Myc and KLF4 are the four Yamanaka factors. When combined, these factors are sufficient to reprogram differentiated cells to an embryonic-like state designated iPS (induced pluripotent stem) cells. iPS cells exhibit the morphology and growth properties of ES cells and express ES cell marker genes.