Overexpression of Sna3 stabilizes tryptophan permease Tat2, potentially competing for the WW domain of Rsp5 ubiquitin ligase with its binding protein Bul1

Hiraki, Toshiki; Abe, Fumiyoshi

doi:10.1016/j.febslet.2009.11.076

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Volume 584, Issue 1 , Pages 55-60, 4 January 2010

Overexpression of Sna3 stabilizes tryptophan permease Tat2, potentially competing for the WW domain of Rsp5 ubiquitin ligase with its binding protein Bul1

Edited by Francesc Posas

Molecular Evolution and Adaptation Research, Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka 237-0061, Japan

Received 25 August 2009; received in revised form 3 November 2009; accepted 20 November 2009. published online 25 November 2009.

Abstract

Tryptophan permease Tat2 in Saccharomyces cerevisiae undergoes Rsp5-dependent degradation upon exposure to high hydrostatic pressure and it limits the growth of tryptophan auxotrophs. Overexpression of SNA3 encoding an endosomal/vacuolar protein possessing the PPAY motif allowed growth at 25MPa, which was potentiated by marked stabilization of Tat2. This appeared to depend on the PPAY motif, which interacted with the WW domain of Rsp5. Subcellular localization of Rsp5 was unchanged by overexpression of either SNA3 or SNA3-AAAY. While the loss of Bul1, a binding protein of Rsp5, or the rsp5-ww3 mutation allowed high-pressure growth, overexpression of BUL1 abolished the Sna3-mediated growth at 25MPa. These results suggest that Sna3 and Bul1 compete for the WW domain of Rsp5 upon Tat2 ubiquitination.