KLF3
Krüppel-like factor 3 is a protein that in humans is encoded by the KLF3 gene.
Structure
KLF3, originally termed Basic Krüppel-like Factor (BKLF), was the third member of the Krüppel-like factor family of zinc finger transcription factors to be discovered. Transcription factors in this family bind DNA by virtue of 3 characteristic three C2H2zinc fingers at their C-termini. Since their DNA-binding domains are highly conserved within the family, all KLF proteins recognize CACCC or CGCCC boxes of the general form NCR CRC CCN, (where N is any base and R is a purine).
Function
While the C-termini are similar in different KLFs, the N-termini vary and accordingly different KLFs can either activate or repress transcription or both. KLF3 appears to function predominantly as a repressor of transcription. It turns genes off. It does this by recruiting the C-terminal Binding Protein co-repressors CTBP1 and CTBP2. CtBP docks onto a short motif (residues 61-65) in the N-terminus of KLF3, of the general form Proline - Isoleucine - Aspartate - Leucine - Serine (the PIDLS motif). CtBP in turn recruits histone modifying enzymes to alter chromatin and repress gene expression.
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