KLF4 (Kruppel-like factor 4, Epithelial zinc finger protein EZF) is a zinc finger transcription factor thought to be involved in developmental differentiation and proliferation. It is considered a pluripotency reprogramming factor (PRF) due to its ability to change cell fate via gene expression conversion. Other PRFs including Sox2, Oct4 and KLF4, as well as a discussion about their capabilities, are reviewed by Jauch et al in hopes of enabling the engineering and optimization of PRFs1.