Deg5,deg8 and the double mutant,deg5deg8 of Arabidopsis thaliana were used to study the physiological role of the DEG proteases in the repair cycle of photosystem II (PSII) under heat stress. PSII activity in deg muta...Deg5,deg8 and the double mutant,deg5deg8 of Arabidopsis thaliana were used to study the physiological role of the DEG proteases in the repair cycle of photosystem II (PSII) under heat stress. PSII activity in deg mutants showed increased sensitivity to heat stress, and the extent of this effect was greater in the double mutant, deg5deg8, than in the single mutants, deg5 and deg8. Degradation of the D1 protein was slower in the mutants than in the WT plants. Furthermore, the levels of other PSII reaction center proteins tested remained relatively stable in the mutant and WT plants following high-temperature treatment. Thus, our results indicate that DEG5 and DEG8 may have synergistic function in degradation of D1 protein under heat stress.展开更多
A T-DNA insertion mutant AtctpA1 was identified to study the physiological roles of a carboxyl-terminal processing protease (CtpA) homologue in Arabidopsis. Under normal growth conditions, disruption of AtctpA1 did no...A T-DNA insertion mutant AtctpA1 was identified to study the physiological roles of a carboxyl-terminal processing protease (CtpA) homologue in Arabidopsis. Under normal growth conditions, disruption of AtctpA1 did not result in any apparent alterations in growth rate and thylakoid membrane protein components. However the mutant plants exhibited increased sensitivity to high irradiance. Degradation of PSII reaction center protein D1 was accelerated in the mutant during photoinhibition. These results demostrated that AtctpA1 was required for efficient repair of PSII in Arabidopsis under high irradiance.展开更多
Deg1,a thylakoid lumen-localized protease,retains both chaperone and protease activities.The in vivo function of Deg1 has been shown to be involved not only in PSII assembly but also in the degradation of PSII reactio...Deg1,a thylakoid lumen-localized protease,retains both chaperone and protease activities.The in vivo function of Deg1 has been shown to be involved not only in PSII assembly but also in the degradation of PSII reaction center protein D1.Here we used the transgenic plants with reduced Deg1 to examine whether the lumen-localized proteins are also the substrates of Deg1 in vivo.Our results showed that the transgenic plants accumulated degradation products of the PsbO protein while the levels of full-length PsbO were not affected.The PsbO degradation products could be efficiently degraded by the recombinant Deg1.These results suggest that Deg1 is involved in the degradation of the PsbO degradation fragments,but not in the initial cleavage event itself.展开更多
The ATP-dependent serine protease Lon belongs to the AAA+ superfamily,which is widely distributed in bacteria,archaea,and eukaryotic cells. Lon participates in the regulation of numerous physiological processes and ge...The ATP-dependent serine protease Lon belongs to the AAA+ superfamily,which is widely distributed in bacteria,archaea,and eukaryotic cells. Lon participates in the regulation of numerous physiological processes and gene expression via degrading various unstable and non-native regulators. In this study,we showed that the Arabidopsis atlon4 mutant is more sensitive to drought stress than wild-type plants. Compared with wild-type plants,atlon4 mutant plants showed increased water loss,decreased water use efficiency,and impaired stomatal closure in drought stress conditions.展开更多
基金the Frontier Project of the Knowledge Innovation Program of the Chinese Academy of Science (Grant No. KJCX2-SW-w29)
文摘Deg5,deg8 and the double mutant,deg5deg8 of Arabidopsis thaliana were used to study the physiological role of the DEG proteases in the repair cycle of photosystem II (PSII) under heat stress. PSII activity in deg mutants showed increased sensitivity to heat stress, and the extent of this effect was greater in the double mutant, deg5deg8, than in the single mutants, deg5 and deg8. Degradation of the D1 protein was slower in the mutants than in the WT plants. Furthermore, the levels of other PSII reaction center proteins tested remained relatively stable in the mutant and WT plants following high-temperature treatment. Thus, our results indicate that DEG5 and DEG8 may have synergistic function in degradation of D1 protein under heat stress.
基金the Frontier Project of Knowledge Innovation Engineering of the Chinese Academy of Sciences (Grant No. KJCX2-SW-w29)
文摘A T-DNA insertion mutant AtctpA1 was identified to study the physiological roles of a carboxyl-terminal processing protease (CtpA) homologue in Arabidopsis. Under normal growth conditions, disruption of AtctpA1 did not result in any apparent alterations in growth rate and thylakoid membrane protein components. However the mutant plants exhibited increased sensitivity to high irradiance. Degradation of PSII reaction center protein D1 was accelerated in the mutant during photoinhibition. These results demostrated that AtctpA1 was required for efficient repair of PSII in Arabidopsis under high irradiance.
基金supported by the State Key Basic Research Program of China(2006CB910300)the National Natural Science Foundation of China(30725003)
文摘Deg1,a thylakoid lumen-localized protease,retains both chaperone and protease activities.The in vivo function of Deg1 has been shown to be involved not only in PSII assembly but also in the degradation of PSII reaction center protein D1.Here we used the transgenic plants with reduced Deg1 to examine whether the lumen-localized proteins are also the substrates of Deg1 in vivo.Our results showed that the transgenic plants accumulated degradation products of the PsbO protein while the levels of full-length PsbO were not affected.The PsbO degradation products could be efficiently degraded by the recombinant Deg1.These results suggest that Deg1 is involved in the degradation of the PsbO degradation fragments,but not in the initial cleavage event itself.
基金supported by the National Basic Research Program of China (2009CB118500)
文摘The ATP-dependent serine protease Lon belongs to the AAA+ superfamily,which is widely distributed in bacteria,archaea,and eukaryotic cells. Lon participates in the regulation of numerous physiological processes and gene expression via degrading various unstable and non-native regulators. In this study,we showed that the Arabidopsis atlon4 mutant is more sensitive to drought stress than wild-type plants. Compared with wild-type plants,atlon4 mutant plants showed increased water loss,decreased water use efficiency,and impaired stomatal closure in drought stress conditions.
