In both unicellular and multicellular organisms, transmembrane （TM） proteins are sorted to and retained at specific membrane domains by endomembrane trafficking mechanisms that recognize sorting signals in the these...In both unicellular and multicellular organisms, transmembrane （TM） proteins are sorted to and retained at specific membrane domains by endomembrane trafficking mechanisms that recognize sorting signals in the these proteins. The trafficking and distribution of plasma membrane （PM）-localized TM proteins （PM proteins）, especially of those PM proteins that show an asymmetric distribution over the PM, has received much attention, as their proper PM localization is crucial for elementary signaling and transport processes, and defects in their localization often lead to severe disease symptoms or developmental defects. The subcellular localization of PM proteins is dynamically regulated by post-translational modifications, such as phosphorylation and ubiquitination. These modificaitons mostly occur on sorting signals that are located in the larger cytosolic domains of the cargo proteins. Here we review the effects of phosphorylation of PM proteins on their trafficking, and present the key examples from the animal field that have been subject to studies for already several decades, such as that of aquaporin 2 and the epidermal growth factor receptor. Our knowledge on cargo trafficking in plants is largely based on studies of the family of PIN FORMED （PIN） carriers that mediate the efflux of the plant hormone auxin. We will review what is known on the subcellular distribution and trafficking of PIN proteins, with a focus on how this is modulated by phosphorylation, and identify and discuss analogies and differences in trafficking with the well-studied animal examples.展开更多
Seed dispersal is an important moment in the life cycle of a plant species. In Arabidopsis thaliana, it is dependent on transcription factor INDEHISCENT （IND）-mediated specification of a separation layer in the dehi...Seed dispersal is an important moment in the life cycle of a plant species. In Arabidopsis thaliana, it is dependent on transcription factor INDEHISCENT （IND）-mediated specification of a separation layer in the dehiscence zone found in the margin between the valves （carpel walls） and the central replum of the developing fruit. It was proposed that IND specifies the separation layer by inducing a local auxin minimum at late stages of fruit development. Here we show that morphological differences between the ind mutant and wild-type fruit already arise at early stages of fruit development, coinciding with strong IND expression in the valve margin. We show that IND-reduced PIN-FORMED3 （PIN3） auxin efflux carrier abundance leads to an increased auxin response in the valve margin during early fruit develop- ment, and that the concomitant cell divisions that form the dehiscence zone are lacking in ind mutant fruit. Moreover, IND promoter-driven ectopic expression of the AGC kinases PINOID （PID） and WAG2 induced indehiscence by expelling auxin from the valve margin at stages 14-16 of fruit development through increased PIN3 abundance. Our results show that IND, besides its role at late stages of Arabi- dopsis fruit development, functions at early stages to facilitate the auxin-triggered cell divisions that form the dehiscence zone.展开更多
All ceiis show some degree of poiarity, either by asymmetrically distributed membrane or cytosolic components. Even in bacterial cells that do not have the eukaryotic membrane compartmentalization of the cytoplasm, pr...All ceiis show some degree of poiarity, either by asymmetrically distributed membrane or cytosolic components. Even in bacterial cells that do not have the eukaryotic membrane compartmentalization of the cytoplasm, proteins can be localized at specific areas. In rod-shaped bacteria, many processes such as signaling, flagella formation, and DNA uptake occur at the cell poles. In addition,展开更多
基金F.H. was supported by grants from the China Scholarship Councilthe Research Council for Chemical Sciences (700.58.301 to R.O.) with fnancial aid from The Netherlands Organization for Scientifc Research
文摘In both unicellular and multicellular organisms, transmembrane （TM） proteins are sorted to and retained at specific membrane domains by endomembrane trafficking mechanisms that recognize sorting signals in the these proteins. The trafficking and distribution of plasma membrane （PM）-localized TM proteins （PM proteins）, especially of those PM proteins that show an asymmetric distribution over the PM, has received much attention, as their proper PM localization is crucial for elementary signaling and transport processes, and defects in their localization often lead to severe disease symptoms or developmental defects. The subcellular localization of PM proteins is dynamically regulated by post-translational modifications, such as phosphorylation and ubiquitination. These modificaitons mostly occur on sorting signals that are located in the larger cytosolic domains of the cargo proteins. Here we review the effects of phosphorylation of PM proteins on their trafficking, and present the key examples from the animal field that have been subject to studies for already several decades, such as that of aquaporin 2 and the epidermal growth factor receptor. Our knowledge on cargo trafficking in plants is largely based on studies of the family of PIN FORMED （PIN） carriers that mediate the efflux of the plant hormone auxin. We will review what is known on the subcellular distribution and trafficking of PIN proteins, with a focus on how this is modulated by phosphorylation, and identify and discuss analogies and differences in trafficking with the well-studied animal examples.
文摘Seed dispersal is an important moment in the life cycle of a plant species. In Arabidopsis thaliana, it is dependent on transcription factor INDEHISCENT （IND）-mediated specification of a separation layer in the dehiscence zone found in the margin between the valves （carpel walls） and the central replum of the developing fruit. It was proposed that IND specifies the separation layer by inducing a local auxin minimum at late stages of fruit development. Here we show that morphological differences between the ind mutant and wild-type fruit already arise at early stages of fruit development, coinciding with strong IND expression in the valve margin. We show that IND-reduced PIN-FORMED3 （PIN3） auxin efflux carrier abundance leads to an increased auxin response in the valve margin during early fruit develop- ment, and that the concomitant cell divisions that form the dehiscence zone are lacking in ind mutant fruit. Moreover, IND promoter-driven ectopic expression of the AGC kinases PINOID （PID） and WAG2 induced indehiscence by expelling auxin from the valve margin at stages 14-16 of fruit development through increased PIN3 abundance. Our results show that IND, besides its role at late stages of Arabi- dopsis fruit development, functions at early stages to facilitate the auxin-triggered cell divisions that form the dehiscence zone.
文摘All ceiis show some degree of poiarity, either by asymmetrically distributed membrane or cytosolic components. Even in bacterial cells that do not have the eukaryotic membrane compartmentalization of the cytoplasm, proteins can be localized at specific areas. In rod-shaped bacteria, many processes such as signaling, flagella formation, and DNA uptake occur at the cell poles. In addition,
