1
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Yu CW, Nguyen VC, Barroga NAM, Nakamura Y, Li HM. Plastid LPAT1 is an integral inner envelope membrane protein with the acyltransferase domain located in the stroma. PLANT CELL REPORTS 2024; 43:257. [PMID: 39382709 DOI: 10.1007/s00299-024-03347-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2024] [Accepted: 09/30/2024] [Indexed: 10/10/2024]
Abstract
KEY MESSAGE The N-terminal transmembrane domain of LPAT1 crosses the inner membrane placing the N terminus in the intermembrane space and the C-terminal enzymatic domain in the stroma. Galactolipids mono- and di-galactosyl diacylglycerol are the major and vital lipids of photosynthetic membranes. They are synthesized by five enzymes hosted at different sub-chloroplast locations. However, localization and topology of the second-acting enzyme, lysophosphatidic acid acyltransferase 1 (LPAT1), which acylates the sn-2 position of glycerol-3-phosphate (G3P) to produce phosphatidic acid (PA), remain unclear. It is not known whether LPAT1 is located at the outer or the inner envelope membrane and whether its enzymatic domain faces the cytosol, the intermembrane space, or the stroma. Even the size of mature LPAT1 in chloroplasts is not known. More information is essential for understanding the pathways of metabolite flow and for future engineering endeavors to modify glycerolipid biosynthesis. We used LPAT1 preproteins translated in vitro for import assays to determine the precise size of the mature protein and found that the LPAT1 transit peptide is at least 85 residues in length, substantially longer than previously predicted. A construct comprising LPAT1 fused to the Venus fluorescent protein and driven by the LPAT1 promoter was used to complement an Arabidopsis lpat1 knockout mutant. To determine the sub-chloroplast location and topology of LPAT1, we performed protease treatment and alkaline extraction using chloroplasts containing in vitro-imported LPAT1 and chloroplasts isolated from LPAT1-Venus-complemented transgenic plants. We show that LPAT1 traverses the inner membrane via an N-terminal transmembrane domain, with its N terminus protruding into the intermembrane space and the C-terminal enzymatic domain residing in the stroma, hence displaying a different membrane topology from its bacterial homolog, PlsC.
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Affiliation(s)
- Chun-Wei Yu
- Institute of Molecular Biology, Academia Sinica, Taipei, 11529, Taiwan
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei, 10617, Taiwan
| | - Van C Nguyen
- RIKEN Center for Sustainable Resource Science (CSRS), Yokohama, 230-0045, Japan
| | - Niña Alyssa M Barroga
- RIKEN Center for Sustainable Resource Science (CSRS), Yokohama, 230-0045, Japan
- Institute of Biological Chemistry, Washington State University, Pullman, USA
| | - Yuki Nakamura
- RIKEN Center for Sustainable Resource Science (CSRS), Yokohama, 230-0045, Japan
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, 113-8654, Japan
| | - Hsou-Min Li
- Institute of Molecular Biology, Academia Sinica, Taipei, 11529, Taiwan.
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2
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Liang K, Zhan X, Li Y, Yang Y, Xie Y, Jin Z, Xu X, Zhang W, Lu Y, Zhang S, Zou Y, Feng S, Wu J, Yan Z. Conservation and specialization of the Ycf2-FtsHi chloroplast protein import motor in green algae. Cell 2024; 187:5638-5650.e18. [PMID: 39197449 DOI: 10.1016/j.cell.2024.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 05/31/2024] [Accepted: 08/05/2024] [Indexed: 09/01/2024]
Abstract
The protein import motor in chloroplasts plays a pivotal role in their biogenesis and homeostasis by driving the translocation of preproteins into chloroplasts. While the Ycf2-FtsHi complex serves as the import motor in land plants, its evolutionary conservation, specialization, and mechanisms across photosynthetic organisms are largely unexplored. Here, we isolated and determined the cryogenic electron microscopy (cryo-EM) structures of the native Ycf2-FtsHi complex from Chlamydomonas reinhardtii, uncovering a complex composed of up to 19 subunits, including multiple green-algae-specific components. The heterohexameric AAA+ ATPase motor module is tilted, potentially facilitating preprotein handover from the translocon at the inner chloroplast membrane (TIC) complex. Preprotein interacts with Ycf2-FtsHi and enhances its ATPase activity in vitro. Integrating Ycf2-FtsHi and translocon at the outer chloroplast membrane (TOC)-TIC supercomplex structures reveals insights into their physical and functional interplay during preprotein translocation. By comparing these findings with those from land plants, our study establishes a structural foundation for understanding the assembly, function, evolutionary conservation, and diversity of chloroplast protein import motors.
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Affiliation(s)
- Ke Liang
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310024, China; Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Xiechao Zhan
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Yuxin Li
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310024, China; Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Yi Yang
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Yanqiu Xie
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Zeyu Jin
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Xiaoyan Xu
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Mass Spectrometry & Metabolomics Core Facility, The Biomedical Research Core Facility, Westlake University, Hangzhou, Zhejiang 310024, China
| | - Wenwen Zhang
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Mass Spectrometry & Metabolomics Core Facility, The Biomedical Research Core Facility, Westlake University, Hangzhou, Zhejiang 310024, China
| | - Yang Lu
- Westlake Four-Dimensional Dynamic Metabolomics (Meta4D) Lab, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Research Center for the Industries of the Future, Westlake University, Hangzhou, Zhejiang, China
| | - Sheng Zhang
- Westlake Four-Dimensional Dynamic Metabolomics (Meta4D) Lab, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Research Center for the Industries of the Future, Westlake University, Hangzhou, Zhejiang, China
| | - Yilong Zou
- Westlake Four-Dimensional Dynamic Metabolomics (Meta4D) Lab, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Research Center for the Industries of the Future, Westlake University, Hangzhou, Zhejiang, China
| | - Shan Feng
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Mass Spectrometry & Metabolomics Core Facility, The Biomedical Research Core Facility, Westlake University, Hangzhou, Zhejiang 310024, China
| | - Jianping Wu
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Zhen Yan
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China.
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3
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Liang K, Jin Z, Zhan X, Li Y, Xu Q, Xie Y, Yang Y, Wang S, Wu J, Yan Z. Structural insights into the chloroplast protein import in land plants. Cell 2024; 187:5651-5664.e18. [PMID: 39197452 DOI: 10.1016/j.cell.2024.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 05/16/2024] [Accepted: 08/05/2024] [Indexed: 09/01/2024]
Abstract
Chloroplast proteins are imported via the translocon at the outer chloroplast membrane (TOC)-translocon at the inner chloroplast membrane (TIC) supercomplex, driven by an ATPase motor. The Ycf2-FtsHi complex has been identified as the chloroplast import motor. However, its assembly and cooperation with the TIC complex during preprotein translocation remain unclear. Here, we present the structures of the Ycf2-FtsHi and TIC complexes from Arabidopsis and an ultracomplex formed between them from Pisum. The Ycf2-FtsHi structure reveals a heterohexameric AAA+ ATPase motor module with characteristic features. Four previously uncharacterized components of Ycf2-FtsHi were identified, which aid in complex assembly and anchoring of the motor module at a tilted angle relative to the membrane. When considering the structures of the TIC complex and the TIC-Ycf2-FtsHi ultracomplex together, it becomes evident that the tilted motor module of Ycf2-FtsHi enables its close contact with the TIC complex, thereby facilitating efficient preprotein translocation. Our study provides valuable structural insights into the chloroplast protein import process in land plants.
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Affiliation(s)
- Ke Liang
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Zeyu Jin
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Xiechao Zhan
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Yuxin Li
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Qikui Xu
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Yanqiu Xie
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Yi Yang
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Shaojie Wang
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Jianping Wu
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Zhen Yan
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China.
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4
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Liu M, Chen L, Gu S, Zhang A, Tong M, Wang S, Wang J, Zhu Y, Zhang J, Sun Y, Guo Y, Li R. Arabidopsis TIC236 contributes to proplastid development and chloroplast biogenesis during embryogenesis. FRONTIERS IN PLANT SCIENCE 2024; 15:1424994. [PMID: 39246812 PMCID: PMC11377289 DOI: 10.3389/fpls.2024.1424994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Accepted: 08/01/2024] [Indexed: 09/10/2024]
Abstract
Plastids are essential, semi-autonomous organelles in plants that carry out a multitude of functions during development. Plastids existing in different subtypes are derived from proplastids progenitors and interconvert in response to environmental and growth cues. Most efforts focus on the differentiation from proplastid to other forms. However, the studies of proplastid development are insufficient and whether proplastid biogenesis affects plant growth is yet to be determined. Arabidopsis TIC236, a translocon component at the inner membrane of the chloroplast envelope, is critical for importing chloroplast-targeted preproteins and chloroplast division. In this study, we uncovered the fundamental influence of proplastid biogenesis on embryo development by exploring the function of TIC236 during embryogenesis. Widespread and strong expression of TIC236 was observed in leaves and embryos. The null mutant tic236 had an embryo-lethal phenotype, with cell division in the mutant embryos delayed starting at the octant stage and arrested at the globular stage. Transmission electron microscopy revealed enlarged proplastids with an aberrant inner structure at the dermatogen and globular stages that ultimately did not differentiate into chloroplasts. Additionally, the fluorescence signal distribution patterns of tic236 embryos carrying the pDR5rev::3xVENUS-N7, pPIN1::PIN1-GFP, pWOX5::GFP, and pSCR::H2B-YFP reporter systems were altered. Together, we provide genetic evidence supporting proplastid biogenesis plays a vital role in embryo development and TIC236 is identified as an indispensable player, ensuring normal proplastid development.
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Affiliation(s)
- Mei Liu
- Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Normal University, Shijiazhuang, China
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang, China
- Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Normal University, Shijiazhuang, China
- Hebei Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang, China
- College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Lifen Chen
- Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Normal University, Shijiazhuang, China
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang, China
- Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Normal University, Shijiazhuang, China
- Hebei Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang, China
- College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Shijie Gu
- Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Normal University, Shijiazhuang, China
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang, China
- Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Normal University, Shijiazhuang, China
- Hebei Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang, China
- College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Aiwei Zhang
- Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Normal University, Shijiazhuang, China
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang, China
- Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Normal University, Shijiazhuang, China
- Hebei Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang, China
- College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Mengjuan Tong
- Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Normal University, Shijiazhuang, China
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang, China
- Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Normal University, Shijiazhuang, China
- Hebei Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang, China
- College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Shuailei Wang
- Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Normal University, Shijiazhuang, China
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang, China
- Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Normal University, Shijiazhuang, China
- Hebei Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang, China
- College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Juntao Wang
- Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Normal University, Shijiazhuang, China
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang, China
- Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Normal University, Shijiazhuang, China
- Hebei Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang, China
- College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Yirui Zhu
- Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Normal University, Shijiazhuang, China
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang, China
- Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Normal University, Shijiazhuang, China
- Hebei Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang, China
- College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Jingsheng Zhang
- Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Normal University, Shijiazhuang, China
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang, China
- Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Normal University, Shijiazhuang, China
- Hebei Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang, China
- College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Yu Sun
- Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Normal University, Shijiazhuang, China
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang, China
- Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Normal University, Shijiazhuang, China
- Hebei Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang, China
- College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Yi Guo
- Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Normal University, Shijiazhuang, China
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang, China
- Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Normal University, Shijiazhuang, China
- Hebei Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang, China
- College of Life Sciences, Hebei Normal University, Shijiazhuang, China
| | - Rui Li
- Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Normal University, Shijiazhuang, China
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang, China
- Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Normal University, Shijiazhuang, China
- Hebei Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang, China
- College of Life Sciences, Hebei Normal University, Shijiazhuang, China
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5
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Zhu M, Tang Y, Xie Y, He B, Ding G, Zhou X. Research progress on differentiation and regulation of plant chromoplasts. Mol Biol Rep 2024; 51:810. [PMID: 39001942 DOI: 10.1007/s11033-024-09753-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Accepted: 06/24/2024] [Indexed: 07/15/2024]
Abstract
Carotenoids, natural tetraterpenoids found abundantly in plants, contribute to the diverse colors of plant non-photosynthetic tissues and provide fragrance through their cleavage products, which also play crucial roles in plant growth and development. Understanding the synthesis, degradation, and storage pathways of carotenoids and identifying regulatory factors represents a significant strategy for enhancing plant quality. Chromoplasts serve as the primary plastids responsible for carotenoid accumulation, and their differentiation is linked to the levels of carotenoids, rendering them a subject of substantial research interest. The differentiation of chromoplasts involves alterations in plastid structure and protein import machinery. Additionally, this process is influenced by factors such as the ORANGE (OR) gene, Clp proteases, xanthophyll esterification, and environmental factors. This review shows the relationship between chromoplast and carotenoid accumulation by presenting recent advances in chromoplast structure, the differentiation process, and key regulatory factors, which can also provide a reference for rational exploitation of chromoplasts to enhance plant quality.
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Affiliation(s)
- Mengyao Zhu
- College of Landscape Architecture and Art, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Yunxia Tang
- College of Landscape Architecture and Art, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Yiqing Xie
- Institute of Economic Forestry, Fujian Academy of Forestry, Fuzhou, 350012, China
| | - BingBing He
- College of Landscape Architecture and Art, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Guochang Ding
- College of Landscape Architecture and Art, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
| | - Xingwen Zhou
- College of Architecture and Planning, Fujian University of Technology, Fuzhou, 350118, China.
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6
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Hanson SE, Dowdy T, Larion M, Doyle MT, Bernstein HD. The patatin-like protein PlpD forms structurally dynamic homodimers in the Pseudomonas aeruginosa outer membrane. Nat Commun 2024; 15:4389. [PMID: 38782915 PMCID: PMC11116518 DOI: 10.1038/s41467-024-48756-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 05/13/2024] [Indexed: 05/25/2024] Open
Abstract
Members of the Omp85 superfamily of outer membrane proteins (OMPs) found in Gram-negative bacteria, mitochondria and chloroplasts are characterized by a distinctive 16-stranded β-barrel transmembrane domain and at least one periplasmic POTRA domain. All previously studied Omp85 proteins promote critical OMP assembly and/or protein translocation reactions. Pseudomonas aeruginosa PlpD is the prototype of an Omp85 protein family that contains an N-terminal patatin-like (PL) domain that is thought to be translocated across the OM by a C-terminal β-barrel domain. Challenging the current dogma, we find that the PlpD PL-domain resides exclusively in the periplasm and, unlike previously studied Omp85 proteins, PlpD forms a homodimer. Remarkably, the PL-domain contains a segment that exhibits unprecedented dynamicity by undergoing transient strand-swapping with the neighboring β-barrel domain. Our results show that the Omp85 superfamily is more structurally diverse than currently believed and suggest that the Omp85 scaffold was utilized during evolution to generate novel functions.
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Affiliation(s)
- Sarah E Hanson
- Genetics and Biochemistry Branch, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Tyrone Dowdy
- Neuro-Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Mioara Larion
- Neuro-Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Matthew Thomas Doyle
- Genetics and Biochemistry Branch, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.
- Sydney Infectious Diseases Institute and School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, 2006, Australia.
| | - Harris D Bernstein
- Genetics and Biochemistry Branch, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.
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7
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Nair AM, Jiang T, Mu B, Zhao R. Plastid Molecular Chaperone HSP90C Interacts with the SecA1 Subunit of Sec Translocase for Thylakoid Protein Transport. PLANTS (BASEL, SWITZERLAND) 2024; 13:1265. [PMID: 38732479 PMCID: PMC11085213 DOI: 10.3390/plants13091265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 04/24/2024] [Accepted: 04/29/2024] [Indexed: 05/13/2024]
Abstract
The plastid stroma-localized chaperone HSP90C plays a crucial role in maintaining optimal proteostasis within chloroplasts and participates in protein translocation processes. While existing studies have revealed HSP90C's direct interaction with the Sec translocase-dependent client pre-protein PsbO1 and the SecY1 subunit of the thylakoid membrane-bound Sec1 translocase channel system, its direct involvement with the extrinsic homodimeric Sec translocase subunit, SecA1, remains elusive. Employing bimolecular fluorescence complementation (BiFC) assay and other in vitro analyses, we unraveled potential interactions between HSP90C and SecA1. Our investigation revealed dynamic interactions between HSP90C and SecA1 at the thylakoid membrane and stroma. The thylakoid membrane localization of this interaction was contingent upon active HSP90C ATPase activity, whereas their stromal interaction was associated with active SecA1 ATPase activity. Furthermore, we observed a direct interaction between these two proteins by analyzing their ATP hydrolysis activities, and their interaction likely impacts their respective functional cycles. Additionally, using PsbO1, a model Sec translocase client pre-protein, we studied the intricacies of HSP90C's possible involvement in pre-protein translocation via the Sec1 system in chloroplasts. The results suggest a complex nature of the HSP90C-SecA1 interaction, possibly mediated by the Sec client protein. Our studies shed light on the nuanced aspects of HSP90C's engagement in orchestrating pre-protein translocation, and we propose a potential collaborative role of HSP90C with SecA1 in actively facilitating pre-protein transport across the thylakoid membrane.
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Affiliation(s)
| | | | | | - Rongmin Zhao
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON M1C 1A4, Canada; Department of Cell & Systems Biology, University of Toronto, Toronto, ON M5S 3B2, Canada; (A.M.N.); (T.J.); (B.M.)
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8
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Nogales E, Mahamid J. Bridging structural and cell biology with cryo-electron microscopy. Nature 2024; 628:47-56. [PMID: 38570716 PMCID: PMC11211576 DOI: 10.1038/s41586-024-07198-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 02/13/2024] [Indexed: 04/05/2024]
Abstract
Most life scientists would agree that understanding how cellular processes work requires structural knowledge about the macromolecules involved. For example, deciphering the double-helical nature of DNA revealed essential aspects of how genetic information is stored, copied and repaired. Yet, being reductionist in nature, structural biology requires the purification of large amounts of macromolecules, often trimmed off larger functional units. The advent of cryogenic electron microscopy (cryo-EM) greatly facilitated the study of large, functional complexes and generally of samples that are hard to express, purify and/or crystallize. Nevertheless, cryo-EM still requires purification and thus visualization outside of the natural context in which macromolecules operate and coexist. Conversely, cell biologists have been imaging cells using a number of fast-evolving techniques that keep expanding their spatial and temporal reach, but always far from the resolution at which chemistry can be understood. Thus, structural and cell biology provide complementary, yet unconnected visions of the inner workings of cells. Here we discuss how the interplay between cryo-EM and cryo-electron tomography, as a connecting bridge to visualize macromolecules in situ, holds great promise to create comprehensive structural depictions of macromolecules as they interact in complex mixtures or, ultimately, inside the cell itself.
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Affiliation(s)
- Eva Nogales
- Molecular and Cell Biology Department, Institute for Quantitative Biomedicine, University of California, Berkeley, CA, USA.
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Howard Hughes Medical Institute, Berkeley, CA, USA.
| | - Julia Mahamid
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
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9
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Yoshimura R, Minamikawa S, Suzuki T, Goto K, Latrasse D, Sicar S, Raynaud C, Benhamed M, Yoshioka Y. CRUMPLED LEAF supports plastid OUTER ENVELOPE PROTEIN OF 80 KDA complex formation in Arabidopsis. PLANT PHYSIOLOGY 2024; 194:2422-2433. [PMID: 38235762 DOI: 10.1093/plphys/kiae005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 11/17/2023] [Accepted: 11/22/2023] [Indexed: 01/19/2024]
Abstract
Embedded β-barrel proteins in the outer envelope membrane mediate most cellular trafficking between the cytoplasm and plastids. Although the TRANSLOCON AT THE OUTER ENVELOPE MEMBRANE OF CHLOROPLASTS 75-V (TOC75-V)/OUTER ENVELOPE PROTEIN OF 80 KDA (OEP80) complex has been implicated in the insertion and assembly of β-barrel proteins in the outer envelope membrane of Arabidopsis (Arabidopsis thaliana) chloroplasts, relatively little is known about this process. CRUMPLED LEAF (CRL) encodes a chloroplast outer envelope membrane-localized protein, and its loss-of-function mutation results in pleiotropic defects, including altered plant morphogenesis, growth retardation, suppression of plastid division, and spontaneous light intensity-dependent localized cell death. A suppressor screen conducted on mutagenized crl mutants revealed that a missense mutation in OEP80 suppresses the pleiotropic defects of crl. Furthermore, we found that OEP80 complex formation is compromised in crl. Additionally, we demonstrated that CRL interacts with OEP80 in vivo and that a portion of CRL is present at the same molecular weight as the OEP80 complex. Our results suggest that CRL interacts with OEP80 to facilitate its complex formation. CRL is involved in plastid protein import; therefore, the pleiotropic defects in crl are likely due to the combined effects of decreased plastid protein import and altered membrane integration of β-barrel proteins in the outer envelope membrane. This study sheds light on the mechanisms that allow β-barrel protein integration into the plastid outer envelope membrane and the importance of this finding for plant cellular processes.
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Affiliation(s)
- Ryo Yoshimura
- Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Syun Minamikawa
- Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Takamasa Suzuki
- Department of Biological Chemistry, College of Bioscience and Biotechnology, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan
| | - Kotaro Goto
- Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - David Latrasse
- CNRS, INRAE, Univ Evry, Institute of Plant Sciences Paris-Saclay (IPS2), Université Paris-Saclay, 91405 Orsay, France
- CNRS, INRAE, Institute of Plant Sciences Paris-Saclay (IPS2), Université de Paris, 91405 Orsay, France
| | - Sanchari Sicar
- CNRS, INRAE, Univ Evry, Institute of Plant Sciences Paris-Saclay (IPS2), Université Paris-Saclay, 91405 Orsay, France
- CNRS, INRAE, Institute of Plant Sciences Paris-Saclay (IPS2), Université de Paris, 91405 Orsay, France
| | - Cécile Raynaud
- CNRS, INRAE, Univ Evry, Institute of Plant Sciences Paris-Saclay (IPS2), Université Paris-Saclay, 91405 Orsay, France
- CNRS, INRAE, Institute of Plant Sciences Paris-Saclay (IPS2), Université de Paris, 91405 Orsay, France
| | - Moussa Benhamed
- CNRS, INRAE, Univ Evry, Institute of Plant Sciences Paris-Saclay (IPS2), Université Paris-Saclay, 91405 Orsay, France
- CNRS, INRAE, Institute of Plant Sciences Paris-Saclay (IPS2), Université de Paris, 91405 Orsay, France
- Institut Universitaire de France (IUF)
| | - Yasushi Yoshioka
- Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
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10
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Mehra HS, Wang X, Russell BP, Kulkarni N, Ferrari N, Larson B, Vinyard DJ. Assembly and Repair of Photosystem II in Chlamydomonas reinhardtii. PLANTS (BASEL, SWITZERLAND) 2024; 13:811. [PMID: 38592843 PMCID: PMC10975043 DOI: 10.3390/plants13060811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 03/05/2024] [Accepted: 03/07/2024] [Indexed: 04/11/2024]
Abstract
Oxygenic photosynthetic organisms use Photosystem II (PSII) to oxidize water and reduce plastoquinone. Here, we review the mechanisms by which PSII is assembled and turned over in the model green alga Chlamydomonas reinhardtii. This species has been used to make key discoveries in PSII research due to its metabolic flexibility and amenability to genetic approaches. PSII subunits originate from both nuclear and chloroplastic gene products in Chlamydomonas. Nuclear-encoded PSII subunits are transported into the chloroplast and chloroplast-encoded PSII subunits are translated by a coordinated mechanism. Active PSII dimers are built from discrete reaction center complexes in a process facilitated by assembly factors. The phosphorylation of core subunits affects supercomplex formation and localization within the thylakoid network. Proteolysis primarily targets the D1 subunit, which when replaced, allows PSII to be reactivated and completes a repair cycle. While PSII has been extensively studied using Chlamydomonas as a model species, important questions remain about its assembly and repair which are presented here.
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Affiliation(s)
| | | | | | | | | | | | - David J. Vinyard
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA; (H.S.M.); (X.W.); (B.P.R.); (N.K.); (N.F.); (B.L.)
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11
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Nieto-Panqueva F, Rubalcava-Gracia D, Hamel PP, González-Halphen D. The constraints of allotopic expression. Mitochondrion 2023; 73:30-50. [PMID: 37739243 DOI: 10.1016/j.mito.2023.09.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 08/28/2023] [Accepted: 09/18/2023] [Indexed: 09/24/2023]
Abstract
Allotopic expression is the functional transfer of an organellar gene to the nucleus, followed by synthesis of the gene product in the cytosol and import into the appropriate organellar sub compartment. Here, we focus on mitochondrial genes encoding OXPHOS subunits that were naturally transferred to the nucleus, and critically review experimental evidence that claim their allotopic expression. We emphasize aspects that may have been overlooked before, i.e., when modifying a mitochondrial gene for allotopic expression━besides adapting the codon usage and including sequences encoding mitochondrial targeting signals━three additional constraints should be considered: (i) the average apparent free energy of membrane insertion (μΔGapp) of the transmembrane stretches (TMS) in proteins earmarked for the inner mitochondrial membrane, (ii) the final, functional topology attained by each membrane-bound OXPHOS subunit; and (iii) the defined mechanism by which the protein translocator TIM23 sorts cytosol-synthesized precursors. The mechanistic constraints imposed by TIM23 dictate the operation of two pathways through which alpha-helices in TMS are sorted, that eventually determine the final topology of membrane proteins. We used the biological hydrophobicity scale to assign an average apparent free energy of membrane insertion (μΔGapp) and a "traffic light" color code to all TMS of OXPHOS membrane proteins, thereby predicting which are more likely to be internalized into mitochondria if allotopically produced. We propose that the design of proteins for allotopic expression must make allowance for μΔGapp maximization of highly hydrophobic TMS in polypeptides whose corresponding genes have not been transferred to the nucleus in some organisms.
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Affiliation(s)
- Felipe Nieto-Panqueva
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Diana Rubalcava-Gracia
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico; Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Patrice P Hamel
- Department of Molecular Genetics and Department of Biological Chemistry and Pharmacology, Ohio State University, Columbus, OH, USA; Vellore Institute of Technology (VIT), School of BioScience and Technology, Vellore, Tamil Nadu, India
| | - Diego González-Halphen
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico.
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12
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Chen J, Yu R, Li N, Deng Z, Zhang X, Zhao Y, Qu C, Yuan Y, Pan Z, Zhou Y, Li K, Wang J, Chen Z, Wang X, Wang X, He SN, Dong J, Deng XW, Chen H. Amyloplast sedimentation repolarizes LAZYs to achieve gravity sensing in plants. Cell 2023; 186:4788-4802.e15. [PMID: 37741279 PMCID: PMC10615846 DOI: 10.1016/j.cell.2023.09.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Revised: 08/04/2023] [Accepted: 09/14/2023] [Indexed: 09/25/2023]
Abstract
Gravity controls directional growth of plants, and the classical starch-statolith hypothesis proposed more than a century ago postulates that amyloplast sedimentation in specialized cells initiates gravity sensing, but the molecular mechanism remains uncharacterized. The LAZY proteins are known as key regulators of gravitropism, and lazy mutants show striking gravitropic defects. Here, we report that gravistimulation by reorientation triggers mitogen-activated protein kinase (MAPK) signaling-mediated phosphorylation of Arabidopsis LAZY proteins basally polarized in root columella cells. Phosphorylation of LAZY increases its interaction with several translocons at the outer envelope membrane of chloroplasts (TOC) proteins on the surface of amyloplasts, facilitating enrichment of LAZY proteins on amyloplasts. Amyloplast sedimentation subsequently guides LAZY to relocate to the new lower side of the plasma membrane in columella cells, where LAZY induces asymmetrical auxin distribution and root differential growth. Together, this study provides a molecular interpretation for the starch-statolith hypothesis: the organelle-movement-triggered molecular polarity formation.
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Affiliation(s)
- Jiayue Chen
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agricultural Sciences and School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Renbo Yu
- State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agricultural Sciences and School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China; Key Laboratory of Vegetable Research Center, Tropical Crops Genetic Resources Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China
| | - Na Li
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Zhaoguo Deng
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Xinxin Zhang
- State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agricultural Sciences and School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Yaran Zhao
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agricultural Sciences and School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Chengfu Qu
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Yanfang Yuan
- State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agricultural Sciences and School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Zhexian Pan
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Yangyang Zhou
- State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agricultural Sciences and School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Kunlun Li
- State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agricultural Sciences and School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Jiajun Wang
- State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agricultural Sciences and School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Zhiren Chen
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Xiaoyi Wang
- State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agricultural Sciences and School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Xiaolian Wang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Shu-Nan He
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Juan Dong
- The Waksman Institute of Microbiology, Rutgers, the State University of New Jersey, Piscataway, NJ 08854, USA; Department of Plant Biology, Rutgers, the State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Xing Wang Deng
- State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agricultural Sciences and School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Haodong Chen
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agricultural Sciences and School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China.
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13
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Nellaepalli S, Lau AS, Jarvis RP. Chloroplast protein translocation pathways and ubiquitin-dependent regulation at a glance. J Cell Sci 2023; 136:jcs241125. [PMID: 37732520 PMCID: PMC10546890 DOI: 10.1242/jcs.241125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2023] Open
Abstract
Chloroplasts conduct photosynthesis and numerous metabolic and signalling processes that enable plant growth and development. Most of the ∼3000 proteins in chloroplasts are nucleus encoded and must be imported from the cytosol. Thus, the protein import machinery of the organelle (the TOC-TIC apparatus) is of fundamental importance for chloroplast biogenesis and operation. Cytosolic factors target chloroplast precursor proteins to the TOC-TIC apparatus, which drives protein import across the envelope membranes into the organelle, before various internal systems mediate downstream routing to different suborganellar compartments. The protein import system is proteolytically regulated by the ubiquitin-proteasome system (UPS), enabling centralized control over the organellar proteome. In addition, the UPS targets a range of chloroplast proteins directly. In this Cell Science at a Glance article and the accompanying poster, we present mechanistic details of these different chloroplast protein targeting and translocation events, and of the UPS systems that regulate chloroplast proteins.
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Affiliation(s)
- Sreedhar Nellaepalli
- Section of Molecular Plant Biology, Department of Biology, University of Oxford, Oxford OX1 3RB, UK
| | - Anne Sophie Lau
- Section of Molecular Plant Biology, Department of Biology, University of Oxford, Oxford OX1 3RB, UK
- Department of Plant Physiology, Faculty of Biology, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - R. Paul Jarvis
- Section of Molecular Plant Biology, Department of Biology, University of Oxford, Oxford OX1 3RB, UK
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14
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Yang Y, Forsythe ES, Ding YM, Zhang DY, Bai WN. Genomic Analysis of Plastid-Nuclear Interactions and Differential Evolution Rates in Coevolved Genes across Juglandaceae Species. Genome Biol Evol 2023; 15:evad145. [PMID: 37515592 PMCID: PMC10410296 DOI: 10.1093/gbe/evad145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 07/07/2023] [Accepted: 07/25/2023] [Indexed: 07/31/2023] Open
Abstract
The interaction between the nuclear and chloroplast genomes in plants is crucial for preserving essential cellular functions in the face of varying rates of mutation, levels of selection, and modes of transmission. Despite this, identifying nuclear genes that coevolve with chloroplast genomes at a genome-wide level has remained a challenge. In this study, we conducted an evolutionary rate covariation analysis to identify candidate nuclear genes coevolving with chloroplast genomes in Juglandaceae. Our analysis was based on 4,894 orthologous nuclear genes and 76 genes across seven chloroplast partitions in nine Juglandaceae species. Our results indicated that 1,369 (27.97%) of the nuclear genes demonstrated signatures of coevolution, with the Ycf1/2 partition yielding the largest number of hits (765) and the ClpP1 partition yielding the fewest (13). These hits were found to be significantly enriched in biological processes related to leaf development, photoperiodism, and response to abiotic stress. Among the seven partitions, AccD, ClpP1, MatK, and RNA polymerase partitions and their respective hits exhibited a narrow range, characterized by dN/dS values below 1. In contrast, the Ribosomal, Photosynthesis, Ycf1/2 partitions and their corresponding hits, displayed a broader range of dN/dS values, with certain values exceeding 1. Our findings highlight the differences in the number of candidate nuclear genes coevolving with the seven chloroplast partitions in Juglandaceae species and the correlation between the evolution rates of these genes and their corresponding chloroplast partitions.
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Affiliation(s)
- Yang Yang
- State Key Laboratory of Earth Surface Processes and Resource Ecology, and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Evan S Forsythe
- Department of Biology, Oregon State University-Cascades, Bend, Oregon, USA
- Integrative Biology Department, Oregon State University, Corvallis, Oregon, USA
| | - Ya-Mei Ding
- State Key Laboratory of Earth Surface Processes and Resource Ecology, and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing, China
- South China Botanical Garden, The Chinese Academy of Sciences, Guangdong, China
| | - Da-Yong Zhang
- State Key Laboratory of Earth Surface Processes and Resource Ecology, and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Wei-Ning Bai
- State Key Laboratory of Earth Surface Processes and Resource Ecology, and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing, China
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15
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Abstract
Protein translocases, such as the bacterial SecY complex, the Sec61 complex of the endoplasmic reticulum (ER) and the mitochondrial translocases, facilitate the transport of proteins across membranes. In addition, they catalyze the insertion of integral membrane proteins into the lipid bilayer. Several membrane insertases cooperate with these translocases, thereby promoting the topogenesis, folding and assembly of membrane proteins. Oxa1 and BamA family members serve as core components in the two major classes of membrane insertases. They facilitate the integration of proteins with α-helical transmembrane domains and of β-barrel proteins into lipid bilayers, respectively. Members of the Oxa1 family were initially found in the internal membranes of bacteria, mitochondria and chloroplasts. Recent studies, however, also identified several Oxa1-type insertases in the ER, where they serve as catalytically active core subunits in the ER membrane protein complex (EMC), the guided entry of tail-anchored (GET) and the GET- and EMC-like (GEL) complex. The outer membrane of bacteria, mitochondria and chloroplasts contain β-barrel proteins, which are inserted by members of the BamA family. In this Cell Science at a Glance article and the accompanying poster, we provide an overview of these different types of membrane insertases and discuss their function.
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Affiliation(s)
- Büsra Kizmaz
- Cell Biology, University of Kaiserslautern, Kaiserslautern 67663, Germany
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16
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Ballabani G, Forough M, Kessler F, Shanmugabalaji V. The journey of preproteins across the chloroplast membrane systems. Front Physiol 2023; 14:1213866. [PMID: 37324391 PMCID: PMC10267391 DOI: 10.3389/fphys.2023.1213866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 05/22/2023] [Indexed: 06/17/2023] Open
Abstract
The photosynthetic capacity of chloroplasts is vital for autotrophic growth in algae and plants. The origin of the chloroplast has been explained by the endosymbiotic theory that proposes the engulfment of a cyanobacterium by an ancestral eukaryotic cell followed by the transfer of many cyanobacterial genes to the host nucleus. As a result of the gene transfer, the now nuclear-encoded proteins acquired chloroplast targeting peptides (known as transit peptides; transit peptide) and are translated as preproteins in the cytosol. Transit peptides contain specific motifs and domains initially recognized by cytosolic factors followed by the chloroplast import components at the outer and inner envelope of the chloroplast membrane. Once the preprotein emerges on the stromal side of the chloroplast protein import machinery, the transit peptide is cleaved by stromal processing peptidase. In the case of thylakoid-localized proteins, cleavage of the transit peptides may expose a second targeting signal guiding the protein to the thylakoid lumen or allow insertion into the thylakoid membrane by internal sequence information. This review summarizes the common features of targeting sequences and describes their role in routing preproteins to and across the chloroplast envelope as well as the thylakoid membrane and lumen.
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Affiliation(s)
| | | | - Felix Kessler
- *Correspondence: Felix Kessler, ; Venkatasalam Shanmugabalaji,
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17
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Shanmugabalaji V, Kessler F. Shining light on the chloroplast protein import machinery of plants. Structure 2023; 31:509-510. [PMID: 37146573 DOI: 10.1016/j.str.2023.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 04/03/2023] [Accepted: 04/03/2023] [Indexed: 05/07/2023]
Abstract
Sunny days for chloroplast protein import: Srinivasan et al. (2023) report on the isolation and provide the first structural information on the pea TOC complex that mediates protein translocation across the outer chloroplast membrane. While two cryoEM structures for algal import complexes have been published, this is the gateway to long-sought-after structures from land plants.
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Affiliation(s)
| | - Felix Kessler
- Plant Physiology Laboratory, University of Neuchâtel, Neuchâtel, Switzerland.
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18
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Srinivasan K, Erramilli SK, Chakravarthy S, Gonzalez A, Kossiakoff A, Noinaj N. Characterization of synthetic antigen binding fragments targeting Toc75 for the isolation of TOC in A. thaliana and P. sativum. Structure 2023; 31:595-606.e5. [PMID: 36977410 PMCID: PMC10164082 DOI: 10.1016/j.str.2023.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 12/21/2022] [Accepted: 03/02/2023] [Indexed: 03/29/2023]
Abstract
Roughly 95% of the proteins that make up the chloroplast must be imported from the cytoplasm. The machinery responsible for the translocation of these cargo proteins is called the translocon at the outer membrane of chloroplast (TOC). The TOC core consists of three proteins, Toc34, Toc75, and Toc159; no high-resolution structure has been solved of fully assembled TOC from plants. Efforts toward determining the structure of the TOC have been hindered almost entirely by difficulties in producing sufficient yields for structural studies. In this study, we introduce an innovative method that utilizes synthetic antigen binding fragments (sABs) to isolate TOC directly from wild-type plant biomass including A. thaliana and P. sativum. Binding between the sABs and the POTRA domains was characterized by size-exclusion chromatography coupled with small-angle X-ray scattering (SEC-SAXS), X-ray crystallography, and isothermal titration calorimetry. We also demonstrate the isolation of the TOC from P. sativum, laying the framework for large-scale isolation and purification of TOC for functional and structural studies.
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Affiliation(s)
- Karthik Srinivasan
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Satchal K Erramilli
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Srinivas Chakravarthy
- The Biophysics Collaborative Access Team (BioCAT), Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL, USA
| | - Adrian Gonzalez
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Anthony Kossiakoff
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Nicholas Noinaj
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA.
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19
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Hanson SE, Doyle MT, Bernstein HD. The patatin-like protein PlpD forms novel structurally dynamic homodimers in the Pseudomonas aeruginosa outer membrane. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.17.537245. [PMID: 37333265 PMCID: PMC10274916 DOI: 10.1101/2023.04.17.537245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Members of the Omp85 superfamily of outer membrane proteins (OMPs) found in Gram-negative bacteria, mitochondria and chloroplasts are characterized by a distinctive 16-stranded β-barrel transmembrane domain and at least one periplasmic POTRA domain. All previously studied Omp85 proteins promote critical OMP assembly and/or protein translocation reactions. Pseudomonas aeruginosa PlpD is the prototype of an Omp85 protein family that contains an N-terminal patatin-like (PL) domain that is thought to be translocated across the OM by a C-terminal β-barrel domain. Challenging the current dogma, we found that the PlpD PL-domain resides exclusively in the periplasm and, unlike previously studied Omp85 proteins, PlpD forms a homodimer. Remarkably, the PL-domain contains a segment that exhibits unprecedented dynamicity by undergoing transient strand-swapping with the neighboring β-barrel domain. Our results show that the Omp85 superfamily is more structurally diverse than currently believed and suggest that the Omp85 scaffold was utilized during evolution to generate novel functions.
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Affiliation(s)
- Sarah E. Hanson
- Genetics and Biochemistry Branch, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892 USA
| | | | - Harris D. Bernstein
- Genetics and Biochemistry Branch, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892 USA
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