Transcriptional activator. Important for maintenance of pluripotency in embryonic stem cells. Binds directly to the POU5F1 distal enhancer and the NANOG proximal promoter, and enhances expression of both genes. Can also bind to numerous other gene promoters and regulates expression of many other pluripotency factors, either directly or indirectly. Promotes inhibition of MAPK signaling during embryonic stem cell differentiation. Interacts with POU5F1. Mainly found in the nucleus. Significantly enhances POU5F1/OCT4-SOX2-KLF4-MYC (OSKM) mediated reprogramming of mouse embryonic fibroblasts into induced pluripotent stem cells, and can also substitute for SOX2 in this process. Belongs to the krueppel C2H2-type zinc-finger protein family.