{"title":"Highlight: on the past and the future of cellular microcompartments.","authors":"Milos Galic, Christian Ungermann, Katia Cosentino","doi":"10.1515/hsz-2023-0153","DOIUrl":"https://doi.org/10.1515/hsz-2023-0153","url":null,"abstract":"","PeriodicalId":8885,"journal":{"name":"Biological Chemistry","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9307013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Classical fluorescence microscopy is a powerful technique to image biological specimen under close-to-native conditions, but light diffraction limits its optical resolution to 200-300 nm-two orders of magnitude worse than the size of biomolecules. Assuming single fluorescent emitters, the final image of the optical system can be described by a convolution with the point spread function (PSF) smearing out details below the size of the PSF. In mathematical terms, fluorescence microscopy produces bandlimited space-continuous images that can be recovered from their spatial samples under the conditions of the classical Shannon-Nyquist theorem. During the past two decades, several single molecule localization techniques have been established and these allow for the determination of molecular positions with sub-pixel accuracy. Without noise, single emitter positions can be recovered precisely - no matter how close they are. We review recent work on the computational resolution limit with a sharp phase transition between two scenarios: 1) where emitters are well-separated with respect to the bandlimit and can be recovered up to the noise level and 2) closely distributed emitters which results in a strong noise amplification in the worst case. We close by discussing additional pitfalls using single molecule localization techniques based on structured illumination.
{"title":"Computational resolution in single molecule localization - impact of noise level and emitter density.","authors":"Mathias Hockmann, Stefan Kunis, Rainer Kurre","doi":"10.1515/hsz-2022-0301","DOIUrl":"https://doi.org/10.1515/hsz-2022-0301","url":null,"abstract":"<p><p>Classical fluorescence microscopy is a powerful technique to image biological specimen under close-to-native conditions, but light diffraction limits its optical resolution to 200-300 nm-two orders of magnitude worse than the size of biomolecules. Assuming single fluorescent emitters, the final image of the optical system can be described by a convolution with the point spread function (PSF) smearing out details below the size of the PSF. In mathematical terms, fluorescence microscopy produces bandlimited space-continuous images that can be recovered from their spatial samples under the conditions of the classical Shannon-Nyquist theorem. During the past two decades, several single molecule localization techniques have been established and these allow for the determination of molecular positions with sub-pixel accuracy. Without noise, single emitter positions can be recovered precisely - no matter how close they are. We review recent work on the computational resolution limit with a sharp phase transition between two scenarios: 1) where emitters are well-separated with respect to the bandlimit and can be recovered up to the noise level and 2) closely distributed emitters which results in a strong noise amplification in the worst case. We close by discussing additional pitfalls using single molecule localization techniques based on structured illumination.</p>","PeriodicalId":8885,"journal":{"name":"Biological Chemistry","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9367349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the CNS communication between neurons occurs at synapses by secretion of neurotransmitter via exocytosis of synaptic vesicles (SVs) at the active zone. Given the limited number of SVs in presynaptic boutons a fast and efficient recycling of exocytosed membrane and proteins by triggered compensatory endocytosis is required to maintain neurotransmission. Thus, pre-synapses feature a unique tight coupling of exo- and endocytosis in time and space resulting in the reformation of SVs with uniform morphology and well-defined molecular composition. This rapid response requires early stages of endocytosis at the peri-active zone to be well choreographed to ensure reformation of SVs with high fidelity. The pre-synapse can address this challenge by a specialized membrane microcompartment, where a pre-sorted and pre-assembled readily retrievable pool (RRetP) of endocytic membrane patches is formed, consisting of the vesicle cargo, presumably bound within a nucleated Clathrin and adaptor complex. This review considers evidence for the RRetP microcompartment to be the primary organizer of presynaptic triggered compensatory endocytosis.
{"title":"The readily retrievable pool of synaptic vesicles.","authors":"Sai Krishnan, Jürgen Klingauf","doi":"10.1515/hsz-2022-0298","DOIUrl":"https://doi.org/10.1515/hsz-2022-0298","url":null,"abstract":"<p><p>In the CNS communication between neurons occurs at synapses by secretion of neurotransmitter via exocytosis of synaptic vesicles (SVs) at the active zone. Given the limited number of SVs in presynaptic boutons a fast and efficient recycling of exocytosed membrane and proteins by triggered compensatory endocytosis is required to maintain neurotransmission. Thus, pre-synapses feature a unique tight coupling of exo- and endocytosis in time and space resulting in the reformation of SVs with uniform morphology and well-defined molecular composition. This rapid response requires early stages of endocytosis at the peri-active zone to be well choreographed to ensure reformation of SVs with high fidelity. The pre-synapse can address this challenge by a specialized membrane microcompartment, where a pre-sorted and pre-assembled readily retrievable pool (RRetP) of endocytic membrane patches is formed, consisting of the vesicle cargo, presumably bound within a nucleated Clathrin and adaptor complex. This review considers evidence for the RRetP microcompartment to be the primary organizer of presynaptic triggered compensatory endocytosis.</p>","PeriodicalId":8885,"journal":{"name":"Biological Chemistry","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9305955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Recent findings expanded our knowledge about plant redox regulation in stress responses by demonstrating that redox processes exert crucial nuclear regulatory functions in meristems and other developmental processes. Analyses of redox-modulated transcription factor functions and coregulatory ROXYs, CC-type land-plant specific glutaredoxins, reveal new insights into the redox control of plant transcription factors and participation of ROXYs in plant development. The role for ROS and redox signaling in response to low-oxygen conditions further strengthens the importance of redox processes in meristems and tissue differentiation as well as for adaptation to changing environments effecting food crop productivity.
{"title":"Nuclear redox processes in land plant development and stress adaptation.","authors":"Sabine Zachgo","doi":"10.1515/hsz-2022-0288","DOIUrl":"https://doi.org/10.1515/hsz-2022-0288","url":null,"abstract":"<p><p>Recent findings expanded our knowledge about plant redox regulation in stress responses by demonstrating that redox processes exert crucial nuclear regulatory functions in meristems and other developmental processes. Analyses of redox-modulated transcription factor functions and coregulatory ROXYs, CC-type land-plant specific glutaredoxins, reveal new insights into the redox control of plant transcription factors and participation of ROXYs in plant development. The role for ROS and redox signaling in response to low-oxygen conditions further strengthens the importance of redox processes in meristems and tissue differentiation as well as for adaptation to changing environments effecting food crop productivity.</p>","PeriodicalId":8885,"journal":{"name":"Biological Chemistry","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9312788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lipids function as the major building blocks of cellular membranes, as signaling molecules and as energy stores for metabolism. These important functions require a precise regulation of lipid biosynthesis, transport, turnover and storage. Lipids are exchanged among organelles through a sophisticated network of vesicular and non-vesicular transport routes. Lysosomes, as the main catabolic organelle, are at the center of this network and have recently evolved as one of the master-regulators of cellular lipid metabolism. Lipids from both endogenous and exogenous sources can be processed, sensed and sorted in and out of the lysosome. In this review, we focus on the role of the lysosome in lipid catabolism, transport and signaling. We highlight recent discoveries on the transport of lipids out of the lysosomal lumen and their exchange with other organelles via membrane contact sites. We also discuss the direct role of lysosomal lipids in the TORC1 signaling pathway, a regulator of cellular metabolism. Finally, we address lysosomal biogenesis, its role in the sorting of lipid metabolic enzymes and the dysregulation of these processes in disease.
{"title":"The role of lysosomes in lipid homeostasis.","authors":"Florian Fröhlich, Ayelén González Montoro","doi":"10.1515/hsz-2022-0287","DOIUrl":"https://doi.org/10.1515/hsz-2022-0287","url":null,"abstract":"<p><p>Lipids function as the major building blocks of cellular membranes, as signaling molecules and as energy stores for metabolism. These important functions require a precise regulation of lipid biosynthesis, transport, turnover and storage. Lipids are exchanged among organelles through a sophisticated network of vesicular and non-vesicular transport routes. Lysosomes, as the main catabolic organelle, are at the center of this network and have recently evolved as one of the master-regulators of cellular lipid metabolism. Lipids from both endogenous and exogenous sources can be processed, sensed and sorted in and out of the lysosome. In this review, we focus on the role of the lysosome in lipid catabolism, transport and signaling. We highlight recent discoveries on the transport of lipids out of the lysosomal lumen and their exchange with other organelles via membrane contact sites. We also discuss the direct role of lysosomal lipids in the TORC1 signaling pathway, a regulator of cellular metabolism. Finally, we address lysosomal biogenesis, its role in the sorting of lipid metabolic enzymes and the dysregulation of these processes in disease.</p>","PeriodicalId":8885,"journal":{"name":"Biological Chemistry","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9317347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mechanical forces exerted to the plasma membrane induce cell shape changes. These transient shape changes trigger, among others, enrichment of curvature-sensitive molecules at deforming membrane sites. Strikingly, some curvature-sensing molecules not only detect membrane deformation but can also alter the amplitude of forces that caused to shape changes in the first place. This dual ability of sensing and inducing membrane deformation leads to the formation of curvature-dependent self-organizing signaling circuits. How these cell-autonomous circuits are affected by auxiliary parameters from inside and outside of the cell has remained largely elusive. Here, we explore how such factors modulate self-organization at the micro-scale and its emerging properties at the macroscale.
{"title":"Modulation of self-organizing circuits at deforming membranes by intracellular and extracellular factors.","authors":"Anastasiia Sokolova, Milos Galic","doi":"10.1515/hsz-2022-0290","DOIUrl":"https://doi.org/10.1515/hsz-2022-0290","url":null,"abstract":"<p><p>Mechanical forces exerted to the plasma membrane induce cell shape changes. These transient shape changes trigger, among others, enrichment of curvature-sensitive molecules at deforming membrane sites. Strikingly, some curvature-sensing molecules not only detect membrane deformation but can also alter the amplitude of forces that caused to shape changes in the first place. This dual ability of sensing and inducing membrane deformation leads to the formation of curvature-dependent self-organizing signaling circuits. How these cell-autonomous circuits are affected by auxiliary parameters from inside and outside of the cell has remained largely elusive. Here, we explore how such factors modulate self-organization at the micro-scale and its emerging properties at the macroscale.</p>","PeriodicalId":8885,"journal":{"name":"Biological Chemistry","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9311600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
While the FAIR (Findable, Accessible, Interoperable, and Re-usable) principles are well accepted in the scientific community, there are still many challenges in implementing them in the day-to-day scientific process. Data management of microscopy images poses special challenges due to the volume, variety, and many proprietary formats. In particular, appropriate metadata collection, a basic requirement for FAIR data, is a real challenge for scientists due to the technical and content-related aspects. Researchers benefit here from interdisciplinary research network with centralized data management. The typically multimodal structure requires generalized data management and the corresponding acquisition of metadata. Here we report on the establishment of an appropriate infrastructure for the research network by a Core Facility and the development and integration of a software tool MDEmic that allows easy and convenient processing of metadata of microscopy images while providing high flexibility in terms of customization of metadata sets. Since it is also in the interest of the core facility to apply standards regarding the scope and serialization formats to realize successful and sustainable data management for bioimaging, we report on our efforts within the community to define standards in metadata, interfaces, and to reduce the barriers of daily data management.
{"title":"Setting up a data management infrastructure for bioimaging.","authors":"Susanne Kunis, Karen Bernhardt, Michael Hensel","doi":"10.1515/hsz-2022-0304","DOIUrl":"https://doi.org/10.1515/hsz-2022-0304","url":null,"abstract":"<p><p>While the FAIR (<b>F</b>indable, <b>A</b>ccessible, <b>I</b>nteroperable, and <b>R</b>e-usable) principles are well accepted in the scientific community, there are still many challenges in implementing them in the day-to-day scientific process. Data management of microscopy images poses special challenges due to the volume, variety, and many proprietary formats. In particular, appropriate metadata collection, a basic requirement for FAIR data, is a real challenge for scientists due to the technical and content-related aspects. Researchers benefit here from interdisciplinary research network with centralized data management. The typically multimodal structure requires generalized data management and the corresponding acquisition of metadata. Here we report on the establishment of an appropriate infrastructure for the research network by a Core Facility and the development and integration of a software tool MDEmic that allows easy and convenient processing of metadata of microscopy images while providing high flexibility in terms of customization of metadata sets. Since it is also in the interest of the core facility to apply standards regarding the scope and serialization formats to realize successful and sustainable data management for bioimaging, we report on our efforts within the community to define standards in metadata, interfaces, and to reduce the barriers of daily data management.</p>","PeriodicalId":8885,"journal":{"name":"Biological Chemistry","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9312789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tasnim Arroum, Marie-Theres Borowski, Nico Marx, Frank Schmelter, Martin Scholz, Olympia Ekaterini Psathaki, Michael Hippler, José Antonio Enriquez, Karin B Busch
The orchestrated activity of the mitochondrial respiratory or electron transport chain (ETC) and ATP synthase convert reduction power (NADH, FADH2) into ATP, the cell's energy currency in a process named oxidative phosphorylation (OXPHOS). Three out of the four ETC complexes are found in supramolecular assemblies: complex I, III, and IV form the respiratory supercomplexes (SC). The plasticity model suggests that SC formation is a form of adaptation to changing conditions such as energy supply, redox state, and stress. Complex I, the NADH-dehydrogenase, is part of the largest supercomplex (CI + CIII2 + CIVn). Here, we demonstrate the role of NDUFB10, a subunit of the membrane arm of complex I, in complex I and supercomplex assembly on the one hand and bioenergetics function on the other. NDUFB10 knockout was correlated with a decrease of SCAF1, a supercomplex assembly factor, and a reduction of respiration and mitochondrial membrane potential. This likely is due to loss of proton pumping since the CI P P -module is downregulated and the P D -module is completely abolished in NDUFB10 knock outs.
线粒体呼吸链或电子传递链(ETC)和ATP合成酶的协调活动将还原力(NADH, FADH2)转化为ATP,这是细胞在氧化磷酸化(OXPHOS)过程中的能量货币。四种ETC配合物中有三种存在于超分子组装体中:配合物I、III和IV形成呼吸超配合物(SC)。可塑性模型表明,SC的形成是一种适应变化条件的形式,如能量供应、氧化还原状态和应激。复合体I, nadh脱氢酶,是最大的超复合体(CI + CIII2 + CIVn)的一部分。在这里,我们展示了NDUFB10(复合体I膜臂的一个亚基)一方面在复合体I和超复合体组装中的作用,另一方面在生物能量学功能上的作用。NDUFB10基因敲除与SCAF1(一种超复合体组装因子)的降低、呼吸和线粒体膜电位的降低相关。这可能是由于质子泵送的损失,因为在NDUFB10敲除中,CI P P -模块被下调,P D -模块被完全取消。
{"title":"Loss of respiratory complex I subunit NDUFB10 affects complex I assembly and supercomplex formation.","authors":"Tasnim Arroum, Marie-Theres Borowski, Nico Marx, Frank Schmelter, Martin Scholz, Olympia Ekaterini Psathaki, Michael Hippler, José Antonio Enriquez, Karin B Busch","doi":"10.1515/hsz-2022-0309","DOIUrl":"https://doi.org/10.1515/hsz-2022-0309","url":null,"abstract":"<p><p>The orchestrated activity of the mitochondrial respiratory or electron transport chain (ETC) and ATP synthase convert reduction power (NADH, FADH<sub>2</sub>) into ATP, the cell's energy currency in a process named oxidative phosphorylation (OXPHOS). Three out of the four ETC complexes are found in supramolecular assemblies: complex I, III, and IV form the respiratory supercomplexes (SC). The plasticity model suggests that SC formation is a form of adaptation to changing conditions such as energy supply, redox state, and stress. Complex I, the NADH-dehydrogenase, is part of the largest supercomplex (CI + CIII<sub>2</sub> + CIV<sub>n</sub>). Here, we demonstrate the role of NDUFB10, a subunit of the membrane arm of complex I, in complex I and supercomplex assembly on the one hand and bioenergetics function on the other. NDUFB10 knockout was correlated with a decrease of SCAF1, a supercomplex assembly factor, and a reduction of respiration and mitochondrial membrane potential. This likely is due to loss of proton pumping since the CI P <sub><i>P</i></sub> -module is downregulated and the P <sub><i>D</i></sub> -module is completely abolished in NDUFB10 knock outs.</p>","PeriodicalId":8885,"journal":{"name":"Biological Chemistry","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9313652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Stress granules are cytosolic, membraneless RNA-protein complexes that form in the cytosol in response to various stressors. Stress granules form through a process termed liquid-liquid phase separation, which increases the local concentration of RNA and protein within the granules, creates dynamic sorting stations for mRNAs and associated proteins, and modulates the availability of mRNA for protein translation. We introduce the concept that neuronal stress granules act as dynamic cytosolic microcompartments in which their components differentially cycle in and out, monitoring the cellular environment. We discuss that neuronal stress granules have distinctive features and contain substructures in which individual components interact transiently. We describe that neuronal stress granules modulate protein expression at multiple levels and affect the proteoform profile of the cytoskeletal protein tau. We argue that a better knowledge of the regulation of stress granule dynamics in neurons and the modulation of their material state is necessary to understand their function during physiological and pathological stress responses. Finally, we delineate approaches to determine the behavior and regulation of critical stress granule organizers and the physical state of stress granules in living neurons.
{"title":"Neuronal stress granules as dynamic microcompartments: current concepts and open questions.","authors":"Anna-Carina Söhnel, Roland Brandt","doi":"10.1515/hsz-2022-0302","DOIUrl":"https://doi.org/10.1515/hsz-2022-0302","url":null,"abstract":"<p><p>Stress granules are cytosolic, membraneless RNA-protein complexes that form in the cytosol in response to various stressors. Stress granules form through a process termed liquid-liquid phase separation, which increases the local concentration of RNA and protein within the granules, creates dynamic sorting stations for mRNAs and associated proteins, and modulates the availability of mRNA for protein translation. We introduce the concept that neuronal stress granules act as dynamic cytosolic microcompartments in which their components differentially cycle in and out, monitoring the cellular environment. We discuss that neuronal stress granules have distinctive features and contain substructures in which individual components interact transiently. We describe that neuronal stress granules modulate protein expression at multiple levels and affect the proteoform profile of the cytoskeletal protein tau. We argue that a better knowledge of the regulation of stress granule dynamics in neurons and the modulation of their material state is necessary to understand their function during physiological and pathological stress responses. Finally, we delineate approaches to determine the behavior and regulation of critical stress granule organizers and the physical state of stress granules in living neurons.</p>","PeriodicalId":8885,"journal":{"name":"Biological Chemistry","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9367357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Proteolysis is an essential process to maintain cellular homeostasis. One pathway that mediates selective protein degradation and which is in principle conserved throughout the kingdoms of life is the N-degron pathway, formerly called the 'N-end rule'. In the cytosol of eukaryotes and prokaryotes, N-terminal residues can be major determinants of protein stability. While the eukaryotic N-degron pathway depends on the ubiquitin proteasome system, the prokaryotic counterpart is driven by the Clp protease system. Plant chloroplasts also contain such a protease network, which suggests that they might harbor an organelle specific N-degron pathway similar to the prokaryotic one. Recent discoveries indicate that the N-terminal region of proteins affects their stability in chloroplasts and provides support for a Clp-mediated entry point in an N-degron pathway in plastids. This review discusses structure, function and specificity of the chloroplast Clp system, outlines experimental approaches to test for an N-degron pathway in chloroplasts, relates these aspects into general plastid proteostasis and highlights the importance of an understanding of plastid protein turnover.
{"title":"Molecular determinants of protein half-life in chloroplasts with focus on the Clp protease system.","authors":"Lioba Inken Winckler, Nico Dissmeyer","doi":"10.1515/hsz-2022-0320","DOIUrl":"https://doi.org/10.1515/hsz-2022-0320","url":null,"abstract":"<p><p>Proteolysis is an essential process to maintain cellular homeostasis. One pathway that mediates selective protein degradation and which is in principle conserved throughout the kingdoms of life is the N-degron pathway, formerly called the 'N-end rule'. In the cytosol of eukaryotes and prokaryotes, N-terminal residues can be major determinants of protein stability. While the eukaryotic N-degron pathway depends on the ubiquitin proteasome system, the prokaryotic counterpart is driven by the Clp protease system. Plant chloroplasts also contain such a protease network, which suggests that they might harbor an organelle specific N-degron pathway similar to the prokaryotic one. Recent discoveries indicate that the N-terminal region of proteins affects their stability in chloroplasts and provides support for a Clp-mediated entry point in an N-degron pathway in plastids. This review discusses structure, function and specificity of the chloroplast Clp system, outlines experimental approaches to test for an N-degron pathway in chloroplasts, relates these aspects into general plastid proteostasis and highlights the importance of an understanding of plastid protein turnover.</p>","PeriodicalId":8885,"journal":{"name":"Biological Chemistry","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2023-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9314676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}