Amylose content(AC) is the main factor determining the palatability, viscosity, transparency, and digestibility of rice(Oryza sativa)grains. AC in rice grains is mainly controlled by different alleles of the Waxy(Wx) ...Amylose content(AC) is the main factor determining the palatability, viscosity, transparency, and digestibility of rice(Oryza sativa)grains. AC in rice grains is mainly controlled by different alleles of the Waxy(Wx) gene. The AP2/EREBP transcription factor OsEBP89 interacts with the MYC-like protein OsBP5 to synergistically regulate the expression of Wx.Here, we determined that the GLYCOGEN SYNTHASE KINASE 5(OsGSK5, also named SHAGGY-like kinase 41 [OsSK41]) inhibits the transcriptional activation activity of OsEBP89 in rice grains during amylose biosynthesis. The loss of OsSK41 function enhanced Wx expression and increased AC in rice grains. By contrast, the loss of function of OsEBP89 reduced Wx expression and decreased AC in rice grains. OsSK41 interacts with OsEBP89 and phosphorylates four of its sites(Thr-28,Thr-30, Ser-238, and Thr-257), which makes OsEBP89 unstable and attenuates its interaction with OsBP5. Wx promoter activity was relatively weak when regulated by the phosphomimicvariantOsEBP89E–OsBP5but relatively strong when regulated by the nonphosphorylatable variant OsEBP89A–OsBP5.Therefore, OsSK41-mediated phosphorylation of OsEBP89 represents an additional layer of complexity in the regulation of amylose biosynthesis during rice grain development. In addition, our findings provide four possible sites for regulating rice grain AC via precise gene editing.展开更多
Endosomal compartments sort and deliver exogenous lipoprotein-derived cholesterol to the endoplasmic reticulum for regulating cellular cholesterol homeostasis.A large number of studies have focused on the removal of e...Endosomal compartments sort and deliver exogenous lipoprotein-derived cholesterol to the endoplasmic reticulum for regulating cellular cholesterol homeostasis.A large number of studies have focused on the removal of endosomal cholesterol,since its accumulation leads to devastating human diseases.Recent studies suggest that cytoplasmic sterol-binding proteins may be involved in endosomal cholesterol transport.In particular,endosome/lysosome-localized or-associated cholesterol-binding proteins may serve as key mediators of cholesterol removal in a non-vesicular manner.Further characterization of these cholesterol-binding proteins will shed light on the molecular mechanisms that regulate endosomal cholesterol sorting.展开更多
基金financially supported by the Innovation Program of Shanghai Municipal Education Commission (2023ZKZD05)the National Natural Science Foundation of China (31971918, 32172043)+1 种基金the Agriculture Research System of Shanghai, China (Grant No. 202203)the Shanghai Science and Technology Innovation Action Plan Project (22N11900200)。
文摘Amylose content(AC) is the main factor determining the palatability, viscosity, transparency, and digestibility of rice(Oryza sativa)grains. AC in rice grains is mainly controlled by different alleles of the Waxy(Wx) gene. The AP2/EREBP transcription factor OsEBP89 interacts with the MYC-like protein OsBP5 to synergistically regulate the expression of Wx.Here, we determined that the GLYCOGEN SYNTHASE KINASE 5(OsGSK5, also named SHAGGY-like kinase 41 [OsSK41]) inhibits the transcriptional activation activity of OsEBP89 in rice grains during amylose biosynthesis. The loss of OsSK41 function enhanced Wx expression and increased AC in rice grains. By contrast, the loss of function of OsEBP89 reduced Wx expression and decreased AC in rice grains. OsSK41 interacts with OsEBP89 and phosphorylates four of its sites(Thr-28,Thr-30, Ser-238, and Thr-257), which makes OsEBP89 unstable and attenuates its interaction with OsBP5. Wx promoter activity was relatively weak when regulated by the phosphomimicvariantOsEBP89E–OsBP5but relatively strong when regulated by the nonphosphorylatable variant OsEBP89A–OsBP5.Therefore, OsSK41-mediated phosphorylation of OsEBP89 represents an additional layer of complexity in the regulation of amylose biosynthesis during rice grain development. In addition, our findings provide four possible sites for regulating rice grain AC via precise gene editing.
基金supported by research grants from the Ara Parseghian Medical Research Foundationthe National Health and Medical Research Council of Australia(#510271).
文摘Endosomal compartments sort and deliver exogenous lipoprotein-derived cholesterol to the endoplasmic reticulum for regulating cellular cholesterol homeostasis.A large number of studies have focused on the removal of endosomal cholesterol,since its accumulation leads to devastating human diseases.Recent studies suggest that cytoplasmic sterol-binding proteins may be involved in endosomal cholesterol transport.In particular,endosome/lysosome-localized or-associated cholesterol-binding proteins may serve as key mediators of cholesterol removal in a non-vesicular manner.Further characterization of these cholesterol-binding proteins will shed light on the molecular mechanisms that regulate endosomal cholesterol sorting.
