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Cell Research (2005) 15, 92–96. doi:10.1038/sj.cr.7290271
Krüppel-like factors 4 and 5: the yin and yang regulators of cellular proliferation
Amr M GHALEB1, Mandayam O NANDAN1, Sengthong CHANCHEVALAP1, W Brian DALTON1, Irfan M HISAMUDDIN1 and Vincent W YANG1,2
- 1Division of Digestive Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA.
- 2Department of Hematology and Oncology, Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia, USA
Correspondence: Vincent W Yang, Tel: +404-727-5638; Fax: +404-727-5767 E-mail: vyang@emory.edu
Abstract
Krüppel-like factors (KLFs) are evolutionarily conserved zinc finger-containing transcription factors with diverse regulatory functions in cell growth, proliferation, differentiation, and embryogenesis. KLF4 and KLF5 are two closely related members of the KLF family that have a similar tissue distribution in embryos and adults. However, the two KLFs often exhibit opposite effects on regulation of gene transcription, despite binding to similar, if not identical, cis-acting DNA sequences. In addition, KLF4 and 5 exert contrasting effects on cell proliferation in many instances; while KLF4 is an inhibitor of cell growth, KLF5 stimulates proliferation. Here we review the biological properties and biochemical mechanisms of action of the two KLFs in the context of growth regulation.
Keywords:
cancer, cell cycle, KLF, transcription, transformation, zinc fingers
Abbreviations:
BTE, basic transcription element; BTEB2, basic transcription element binding protein 2; CYP1A1, cytochrome P-450IA1; KLF, Krüppel-like factor; MAPK, mitogen-activated protein kinase

