The endoplasmic reticulum quality control(ER-QC)is a conserved mechanism in surveillance of secreted signaling factors during cell-to-cell communication in eukaryotes.Recent data show that the ER-QC plays important ro...The endoplasmic reticulum quality control(ER-QC)is a conserved mechanism in surveillance of secreted signaling factors during cell-to-cell communication in eukaryotes.Recent data show that the ER-QC plays important roles in diverse cell-to-cell signaling processes during immune response,vegetative and reproductive development in plants.Pollen tube guidance is a precisely guided cell-cell communication process between the male and female gametophytes during plant reproduction.Recently,the female signal has been identified as small secreted peptides,but how the pollen tube responds to this signal is still unclear.In this review,we intend to summarize the role of ER-QC in plants and discuss the recent advances regarding our understanding of the mechanism of pollen tube response to the female signals.展开更多
The endoplasmic reticulum-associated degradation （ERAD） is a highly conserved mechanism to remove mis- folded membrane/secretory proteins from the endoplasmic reticulum （ER）. While many of the individual component...The endoplasmic reticulum-associated degradation （ERAD） is a highly conserved mechanism to remove mis- folded membrane/secretory proteins from the endoplasmic reticulum （ER）. While many of the individual components of the ERAD machinery are well characterized in yeast and mammals, our knowledge of a plant ERAD process is rather limited. Here, we report a functional study of an Arabidopsis homolog （AtOS9） of an ER luminal lectin Yos9 （OS-9 in mammals） that recognizes a unique asparagine-linked glycan on misfolded proteins. We discovered that AtOS9 is an ER-Iocalized glyco- protein that is co-expressed with many known/predicted ER chaperones. AT-DNA insertional atos9-t mutation blocks the degradation of a structurally imperfect yet biochemically competent brassinosteroid （BR） receptor bril-9, causing its increased accumulation in the ER and its consequent leakage to the cell surface responsible for restoring the BR sensitivity and suppressing the dwarfism of the bril-9 mutant. In addition, we identified a missense mutation in AtOS9 in a recently discovered ERAD mutant ems-rnutagenized bril suppressor 6 （ebs6-1）. Moreover, we showed that atos9-t also inhibits the ERAD of bril-5, another ER-retained BR receptor, and a misfolded EFR, a BRIl-like receptor for the bacterial translation elongation factor EF-Tu. Furthermore, we found that AtOS9 interacted biochemically and genetically with EBS5, an Arabidopsis homolog of the yeast Hrd3/mammalian SellL known to collaborate with Yos9/OS-9 to select ERAD clients. Taken together, our results demonstrated a functional role of AtOS9 in a plant ERAD process that degrades misfolded receptor-like kinases.展开更多
基金by grants from the Ministry of Science and Technology of China(No.2007CB947600)National Natural Science Foundation of China(Grant Nos.30830063 and 30921003)to W.C.Y.
文摘The endoplasmic reticulum quality control(ER-QC)is a conserved mechanism in surveillance of secreted signaling factors during cell-to-cell communication in eukaryotes.Recent data show that the ER-QC plays important roles in diverse cell-to-cell signaling processes during immune response,vegetative and reproductive development in plants.Pollen tube guidance is a precisely guided cell-cell communication process between the male and female gametophytes during plant reproduction.Recently,the female signal has been identified as small secreted peptides,but how the pollen tube responds to this signal is still unclear.In this review,we intend to summarize the role of ER-QC in plants and discuss the recent advances regarding our understanding of the mechanism of pollen tube response to the female signals.
基金This work was partly supported by grants from National Institutes of Health （GM060519） and National Science Foundation （IOS 1121496） to J.L.
文摘The endoplasmic reticulum-associated degradation （ERAD） is a highly conserved mechanism to remove mis- folded membrane/secretory proteins from the endoplasmic reticulum （ER）. While many of the individual components of the ERAD machinery are well characterized in yeast and mammals, our knowledge of a plant ERAD process is rather limited. Here, we report a functional study of an Arabidopsis homolog （AtOS9） of an ER luminal lectin Yos9 （OS-9 in mammals） that recognizes a unique asparagine-linked glycan on misfolded proteins. We discovered that AtOS9 is an ER-Iocalized glyco- protein that is co-expressed with many known/predicted ER chaperones. AT-DNA insertional atos9-t mutation blocks the degradation of a structurally imperfect yet biochemically competent brassinosteroid （BR） receptor bril-9, causing its increased accumulation in the ER and its consequent leakage to the cell surface responsible for restoring the BR sensitivity and suppressing the dwarfism of the bril-9 mutant. In addition, we identified a missense mutation in AtOS9 in a recently discovered ERAD mutant ems-rnutagenized bril suppressor 6 （ebs6-1）. Moreover, we showed that atos9-t also inhibits the ERAD of bril-5, another ER-retained BR receptor, and a misfolded EFR, a BRIl-like receptor for the bacterial translation elongation factor EF-Tu. Furthermore, we found that AtOS9 interacted biochemically and genetically with EBS5, an Arabidopsis homolog of the yeast Hrd3/mammalian SellL known to collaborate with Yos9/OS-9 to select ERAD clients. Taken together, our results demonstrated a functional role of AtOS9 in a plant ERAD process that degrades misfolded receptor-like kinases.
