Calcium acts as a second messenger for signaling to a variety of stimuli including MAMPs （Microbe-Associated Molecular Patterns）, such as fig22 and elf18 that are derived from bacterial flagellin and elongation fact...Calcium acts as a second messenger for signaling to a variety of stimuli including MAMPs （Microbe-Associated Molecular Patterns）, such as fig22 and elf18 that are derived from bacterial flagellin and elongation factor Tu, respectively. Here, Arabidopsis thaliana mutants with changed calcium elevation （cce） in response to fig22 treatment were isolated and characterized. Besides novel mutant alleles of the fig22 receptor, FLS2 （Flagellin-Sensitive 2）, and the receptor-associated kinase, BAK1 （Brassinosteroid receptor 1-Associated Kinase 1）, the new cce mutants can be categorized into two main groups--those with a reduced or an enhanced calcium elevation. Moreover, cce mutants from both groups show differ- ential phenotypes to different sets of MAMPs. Thus, these mutants will facilitate the discovery of novel components in early MAMP signaling and bridge the gaps in current knowledge of calcium signaling during plant-microbe interactions. Last but not least, the screening method is optimized for speed （covering 384 plants in 3 or 10 h） and can be adapted to genetically dissect any other stimuli that induce a change in calcium levels.展开更多
Eukaryotic cells contain semi-autonomous organelles that have lost most of their coding capacity for essential proteins to the nucleus.Therefore,their functioning depends on the cytosolic translation products of nucle...Eukaryotic cells contain semi-autonomous organelles that have lost most of their coding capacity for essential proteins to the nucleus.Therefore,their functioning depends on the cytosolic translation products of nuclear-encoded genes that must be imported by a specialized protein import machinery.Chloroplasts import between 2500 and 3500 proteins for their functioning,demonstrating that the bulk of the chloroplast proteome is shuttied through the cytosol as precursor proteins.Precursor proteins usually contain an N-terminal transit peptide that is cleaved off by a signa/processing peptidase(SPP)and degraded by the chloroplast protease network upon import.In the cytosol,precursors can be co-and post-translationally modified,interact with a set of chaperones,co-chaperones,14-3-3 proteins,and/or E3 ligases before they are either imported or degraded by the cytosolic proteasome complex.It is now clear that precursors are not only a transient transport form of functional proteins but that their cytosolic transition is of regulatory importance.展开更多
基金This work was supported by a Deutsche Forschungsgemeinschaft (DFG) grant，financed by the DFG grant，by the Swiss National Science Foundation grant
文摘Calcium acts as a second messenger for signaling to a variety of stimuli including MAMPs （Microbe-Associated Molecular Patterns）, such as fig22 and elf18 that are derived from bacterial flagellin and elongation factor Tu, respectively. Here, Arabidopsis thaliana mutants with changed calcium elevation （cce） in response to fig22 treatment were isolated and characterized. Besides novel mutant alleles of the fig22 receptor, FLS2 （Flagellin-Sensitive 2）, and the receptor-associated kinase, BAK1 （Brassinosteroid receptor 1-Associated Kinase 1）, the new cce mutants can be categorized into two main groups--those with a reduced or an enhanced calcium elevation. Moreover, cce mutants from both groups show differ- ential phenotypes to different sets of MAMPs. Thus, these mutants will facilitate the discovery of novel components in early MAMP signaling and bridge the gaps in current knowledge of calcium signaling during plant-microbe interactions. Last but not least, the screening method is optimized for speed （covering 384 plants in 3 or 10 h） and can be adapted to genetically dissect any other stimuli that induce a change in calcium levels.
文摘Eukaryotic cells contain semi-autonomous organelles that have lost most of their coding capacity for essential proteins to the nucleus.Therefore,their functioning depends on the cytosolic translation products of nuclear-encoded genes that must be imported by a specialized protein import machinery.Chloroplasts import between 2500 and 3500 proteins for their functioning,demonstrating that the bulk of the chloroplast proteome is shuttied through the cytosol as precursor proteins.Precursor proteins usually contain an N-terminal transit peptide that is cleaved off by a signa/processing peptidase(SPP)and degraded by the chloroplast protease network upon import.In the cytosol,precursors can be co-and post-translationally modified,interact with a set of chaperones,co-chaperones,14-3-3 proteins,and/or E3 ligases before they are either imported or degraded by the cytosolic proteasome complex.It is now clear that precursors are not only a transient transport form of functional proteins but that their cytosolic transition is of regulatory importance.
