Molecular Evolution and Adaptation Research, Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan.
FEBS Lett. 2010 Jan 4;584(1):55-60. doi: 10.1016/j.febslet.2009.11.076.
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 25 MPa, 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 25 MPa. These results suggest that Sna3 and Bul1 compete for the WW domain of Rsp5 upon Tat2 ubiquitination.
色氨酸通透酶 Tat2 在酿酒酵母中，在受到高静压时会发生依赖于 Rsp5 的降解，从而限制色氨酸营养缺陷型的生长。过表达具有 PPAY 基序的内体/液泡蛋白编码的 SNA3 允许在 25 MPa 下生长，而过表达 Tat2 则显著稳定了 Tat2。这似乎依赖于与 Rsp5 的 WW 结构域相互作用的 PPAY 基序。无论 SNA3 还是 SNA3-AAAY 的过表达都不会改变 Rsp5 的亚细胞定位。虽然 Bul1 的缺失，Rsp5 的结合蛋白，或 rsp5-ww3 突变允许在高压下生长，但 BUL1 的过表达则消除了 Sna3 在 25 MPa 下介导的生长。这些结果表明，在 Tat2 泛素化时，Sna3 和 Bul1 竞争 Rsp5 的 WW 结构域。
