Publications (2)4.63 Total impact
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Article: Ligand-dependent nucleo-cytoplasmic shuttling of peroxisome proliferator-activated receptors, PPARα and PPARγ.
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ABSTRACT: Peroxisome proliferator-activated receptors (PPARs) play important roles in diverse biological processes including metabolisms of sugars and lipids and differentiation of cells such as adipocytes. PPARs are transcription factors belonging to the ligand-dependent hormone receptor group. To function as transcription factors, PPARs translocate into nucleus where they associate with transcription apparatus. However, mechanisms underlying nuclear transport of PPARs remain enigmatic. We show here that PPARα and PPARγ dynamically shuttle between nucleus and cytoplasm, although they constitutively and predominantly appear in nucleus. With a series of truncation mutants, we identify that PPAR nuclear transport is mediated by at least two nuclear localization signals (NLSs) in DNA-binding domain (DBD)-hinge and activation function 1 (AF1) regions and their respective receptors including importinα/β, importin 7, and an unidentified receptor. PPARs also harbor two nuclear export signals in DBD and ligand-binding domain regions that are recognized by distinct export receptors, calreticulin and CRM1. Moreover, we show that nuclear-cytoplasmic shuttling of PPARs is regulated by respective PPAR ligands and Ca2+ concentration. Taken together, we suggest that the multiple pathways for the nuclear-cytoplasmic transport of PPARs regulate the biological functions of PPARs in response to external signals.Genes to Cells 05/2012; 17(7):576-96. · 2.68 Impact Factor -
Article: Nuclear transport of peroxisome-proliferator activated receptor α.
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ABSTRACT: Peroxisome-proliferator activated receptor α (PPARα) is a ligand-activated transcription factor, playing a key role in several essential pathways including lipid metabolism. Although nuclear localization of PPARα is essential for its transactivation activity, mechanisms underlying intracellular traffics of PPARα remain undefined. We here identify and characterize a nuclear localization signal (NLS) residing in the junction between DNA-binding domain and hinge regions of PPARα. The NLS consists of two basic-amino acid clusters locating in the sequence encompassing amino acid residues at 144-187. We evidently show by mutational analysis that the basic residues in this NLS are essential for the nuclear import. Moreover, the PPARα NLS binds well-known nuclear transporters, importin α and importin β, in a manner independent of DNA-binding activity.Journal of biochemistry 03/2011; 149(3):311-9. · 1.95 Impact Factor
