... 1997, 1999; Kamijo et al., 1992). Indeed, both Pxa1p and Pxa2p localize to the peroxisomal me... more ... 1997, 1999; Kamijo et al., 1992). Indeed, both Pxa1p and Pxa2p localize to the peroxisomal membrane and might function as heterodimers (Shani et al., 1996; Swartzman, et al., 1996). They are thought to mediate peroxisomal ...
Exposure of the yeast Saccharomyces cerevisiae to weak organic acids such as the food preservativ... more Exposure of the yeast Saccharomyces cerevisiae to weak organic acids such as the food preservatives sorbate, benzoate and propionate leads to the pronounced induction of the plasma membrane ATP-binding cassette (ABC) transporter, Pdr12p. This protein mediates efflux of weak acid anions, which is essential for stress adaptation. Recently, we identified War1p as the dedicated transcriptional regulator required for PDR12 stress induction. Here, we report the results from a genetic screen that led to the isolation of two war1 alleles encoding mutant variants, War1-28p and War1-42p, which are unable to support cell growth in the presence of sorbate. DNA sequencing revealed that War1-28 encodes a truncated form of the transcriptional regulator, and War1-42 carries three clustered mutations near the C-terminal activation domain. Although War1-42 is expressed and properly localized in the nucleus, the War1-42p variant fails to bind the weak-acid-response elements in the PDR12 promoter, as shown by in vivo footprinting. Importantly, in contrast with wild-type War1p, War1-42p is also no longer phosphorylated upon weak-acid challenge, demonstrating that phosphorylation of War1p, its activation and DNA binding are tightly linked processes that are essential for adaptation to weak-acid stress.
From the skin of Xenopus laevis, the cloned cDNAs of two precursors of thyrotropin-releasing horm... more From the skin of Xenopus laevis, the cloned cDNAs of two precursors of thyrotropin-releasing hormone have been isolated and sequenced. These encode almost identical precursor polypeptides each containing seven copies of the end product flanked by typical prohormones processing signals. Northern blot analysis has corroborated the existence of two thyrotropin-releasing hormone precursor mRNAs of similar size as the cloned cDNA and demonstrated the existence of a third smaller species as well. Two or more mRNAs for this precursor are also present in the brain and eyes of X. laevis adults and tadpoles.
... 1997, 1999; Kamijo et al., 1992). Indeed, both Pxa1p and Pxa2p localize to the peroxisomal me... more ... 1997, 1999; Kamijo et al., 1992). Indeed, both Pxa1p and Pxa2p localize to the peroxisomal membrane and might function as heterodimers (Shani et al., 1996; Swartzman, et al., 1996). They are thought to mediate peroxisomal ...
Exposure of the yeast Saccharomyces cerevisiae to weak organic acids such as the food preservativ... more Exposure of the yeast Saccharomyces cerevisiae to weak organic acids such as the food preservatives sorbate, benzoate and propionate leads to the pronounced induction of the plasma membrane ATP-binding cassette (ABC) transporter, Pdr12p. This protein mediates efflux of weak acid anions, which is essential for stress adaptation. Recently, we identified War1p as the dedicated transcriptional regulator required for PDR12 stress induction. Here, we report the results from a genetic screen that led to the isolation of two war1 alleles encoding mutant variants, War1-28p and War1-42p, which are unable to support cell growth in the presence of sorbate. DNA sequencing revealed that War1-28 encodes a truncated form of the transcriptional regulator, and War1-42 carries three clustered mutations near the C-terminal activation domain. Although War1-42 is expressed and properly localized in the nucleus, the War1-42p variant fails to bind the weak-acid-response elements in the PDR12 promoter, as shown by in vivo footprinting. Importantly, in contrast with wild-type War1p, War1-42p is also no longer phosphorylated upon weak-acid challenge, demonstrating that phosphorylation of War1p, its activation and DNA binding are tightly linked processes that are essential for adaptation to weak-acid stress.
From the skin of Xenopus laevis, the cloned cDNAs of two precursors of thyrotropin-releasing horm... more From the skin of Xenopus laevis, the cloned cDNAs of two precursors of thyrotropin-releasing hormone have been isolated and sequenced. These encode almost identical precursor polypeptides each containing seven copies of the end product flanked by typical prohormones processing signals. Northern blot analysis has corroborated the existence of two thyrotropin-releasing hormone precursor mRNAs of similar size as the cloned cDNA and demonstrated the existence of a third smaller species as well. Two or more mRNAs for this precursor are also present in the brain and eyes of X. laevis adults and tadpoles.
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Papers by Karl Kuchler