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Parra M, Coppola M, Hellmann H. PDX proteins from Arabidopsis thaliana as novel substrates of cathepsin B: implications for vitamin B 6 biosynthesis regulation. FEBS J 2024; 291:2372-2387. [PMID: 38431778 DOI: 10.1111/febs.17110] [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: 05/29/2023] [Revised: 12/18/2023] [Accepted: 02/21/2024] [Indexed: 03/05/2024]
Abstract
Vitamin B6 is a critical molecule for metabolism, development, and stress sensitivity in plants. It is a cofactor for numerous biochemical reactions, can serve as an antioxidant, and has the potential to increase tolerance against both biotic and abiotic stressors. Due to the importance of vitamin B6, its biosynthesis is likely tightly regulated. Plants can synthesize vitamin B6 de novo via the concerted activity of Pyridoxine Biosynthesis Protein 1 (PDX1) and PDX2. Previously, PDX proteins have been identified as targets for ubiquitination, indicating they could be marked for degradation by two highly conserved pathways: the Ubiquitin Proteasome Pathway (UPP) and the autophagy pathway. Initial experiments show that PDXs are in fact degraded, but surprisingly, in a ubiquitin-independent manner. Inhibitor studies pointed toward cathepsin B, a conserved lysosomal cysteine protease, which is implicated in both programed cell death and autophagy in humans and plants. In plants, cathepsin Bs are poorly described, and no confirmed substrates have been identified. Here, we present PDX proteins from Arabidopsis thaliana as interactors and substrates of a plant Cathepsin B. These findings not only describe a novel cathepsin B substrate in plants, but also provide new insights into how plants regulate de novo biosynthesis of vitamin B6.
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Affiliation(s)
- Marcelina Parra
- School of Biological Sciences, Washington State University, Pullman, WA, USA
| | | | - Hanjo Hellmann
- School of Biological Sciences, Washington State University, Pullman, WA, USA
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2
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Hashimi SM, Huang MJ, Amini MQ, Wang WX, Liu TY, Chen Y, Liao LN, Lan HJ, Liu JZ. Silencing GmATG7 Leads to Accelerated Senescence and Enhanced Disease Resistance in Soybean. Int J Mol Sci 2023; 24:16508. [PMID: 38003698 PMCID: PMC10671774 DOI: 10.3390/ijms242216508] [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: 10/07/2023] [Revised: 11/14/2023] [Accepted: 11/16/2023] [Indexed: 11/26/2023] Open
Abstract
Autophagy plays a critical role in nutrient recycling/re-utilizing under nutrient deprivation conditions. However, the role of autophagy in soybeans has not been intensively investigated. In this study, the Autophay-related gene 7 (ATG7) gene in soybeans (referred to as GmATG7) was silenced using a virus-induced gene silencing approach mediated by Bean pod mottle virus (BPMV). Our results showed that ATG8 proteins were highly accumulated in the dark-treated leaves of the GmATG7-silenced plants relative to the vector control leaves (BPMV-0), which is indicative of an impaired autophagy pathway. Consistent with the impaired autophagy, the dark-treated GmATG7-silenced leaves displayed an accelerated senescence phenotype, which was not seen on the dark-treated BPMV-0 leaves. In addition, the accumulation levels of both H2O2 and salicylic acid (SA) were significantly induced in the GmATG7-silenced plants compared with the BPMV-0 plants, indicating an activated immunity. Consistently, the GmATG7-silenced plants were more resistant against both Pseudomonas syringae pv. glycinea (Psg) and Soybean mosaic virus (SMV) compared with the BPMV-0 plants. However, the activated immunity in the GmATG7-silenced plant was not dependent upon the activation of MPK3/MPK6. Collectively, our results demonstrated that the function of GmATG7 is indispensable for autophagy in soybeans, and the activated immunity in the GmATG7-silenced plant is a result of impaired autophagy.
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Affiliation(s)
- Said M. Hashimi
- College of Life Sciences, Zhejiang Normal University, Jinhua 321004, China; (S.M.H.); (M.-J.H.); (M.Q.A.); (W.-X.W.); (T.-Y.L.); (Y.C.); (L.-N.L.); (H.-J.L.)
| | - Min-Jun Huang
- College of Life Sciences, Zhejiang Normal University, Jinhua 321004, China; (S.M.H.); (M.-J.H.); (M.Q.A.); (W.-X.W.); (T.-Y.L.); (Y.C.); (L.-N.L.); (H.-J.L.)
| | - Mohammad Q. Amini
- College of Life Sciences, Zhejiang Normal University, Jinhua 321004, China; (S.M.H.); (M.-J.H.); (M.Q.A.); (W.-X.W.); (T.-Y.L.); (Y.C.); (L.-N.L.); (H.-J.L.)
| | - Wen-Xu Wang
- College of Life Sciences, Zhejiang Normal University, Jinhua 321004, China; (S.M.H.); (M.-J.H.); (M.Q.A.); (W.-X.W.); (T.-Y.L.); (Y.C.); (L.-N.L.); (H.-J.L.)
| | - Tian-Yao Liu
- College of Life Sciences, Zhejiang Normal University, Jinhua 321004, China; (S.M.H.); (M.-J.H.); (M.Q.A.); (W.-X.W.); (T.-Y.L.); (Y.C.); (L.-N.L.); (H.-J.L.)
| | - Yu Chen
- College of Life Sciences, Zhejiang Normal University, Jinhua 321004, China; (S.M.H.); (M.-J.H.); (M.Q.A.); (W.-X.W.); (T.-Y.L.); (Y.C.); (L.-N.L.); (H.-J.L.)
| | - Li-Na Liao
- College of Life Sciences, Zhejiang Normal University, Jinhua 321004, China; (S.M.H.); (M.-J.H.); (M.Q.A.); (W.-X.W.); (T.-Y.L.); (Y.C.); (L.-N.L.); (H.-J.L.)
| | - Hu-Jiao Lan
- College of Life Sciences, Zhejiang Normal University, Jinhua 321004, China; (S.M.H.); (M.-J.H.); (M.Q.A.); (W.-X.W.); (T.-Y.L.); (Y.C.); (L.-N.L.); (H.-J.L.)
- Institute of Genetics and Developmental Biology, Zhejiang Normal University, Jinhua 321004, China
- Zhejiang Provincial Key Laboratory of Biotechnology on Specialty Economic Plants, Zhejiang Normal University, Jinhua 321004, China
| | - Jian-Zhong Liu
- College of Life Sciences, Zhejiang Normal University, Jinhua 321004, China; (S.M.H.); (M.-J.H.); (M.Q.A.); (W.-X.W.); (T.-Y.L.); (Y.C.); (L.-N.L.); (H.-J.L.)
- Institute of Genetics and Developmental Biology, Zhejiang Normal University, Jinhua 321004, China
- Zhejiang Provincial Key Laboratory of Biotechnology on Specialty Economic Plants, Zhejiang Normal University, Jinhua 321004, China
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Li H, Li T, Li Y, Bai H, Dai Y, Liao Y, Wei J, Shen W, Zheng B, Zhang Z, Gao C. The plant FYVE domain-containing protein FREE1 associates with microprocessor components to repress miRNA biogenesis. EMBO Rep 2023; 24:e55037. [PMID: 36373807 PMCID: PMC9827557 DOI: 10.15252/embr.202255037] [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: 03/13/2022] [Revised: 10/15/2022] [Accepted: 10/21/2022] [Indexed: 11/16/2022] Open
Abstract
FYVE domain protein required for endosomal sorting 1 (FREE1), originally identified as a plant-specific component of the endosomal sorting complex required for transport (ESCRT) machinery, plays diverse roles either in endosomal sorting in the cytoplasm or in transcriptional regulation of abscisic acid signaling in the nucleus. However, to date, a role for FREE1 or other ESCRT components in the regulation of plant miRNA biology has not been discovered. Here, we demonstrate a nuclear function of FREE1 as a cofactor in miRNA biogenesis in plants. FREE1 directly interacts with the plant core microprocessor component CPL1 in nuclear bodies and disturbs the association between HYL1, SE and CPL1. Inactivation of FREE1 in the nucleus increases the binding affinity between HYL1, SE, and CPL1 and causes a transition of HYL1 from the inactive hyperphosphorylated version to the active hypophosphorylated form, thereby promoting miRNA biogenesis. Our results suggest that FREE1 has evolved as a negative regulator of miRNA biogenesis and provides evidence for a link between FYVE domain-containing proteins and miRNA biogenesis in plants.
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Affiliation(s)
- Hongbo Li
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life SciencesSouth China Normal UniversityGuangzhouChina
| | - Tingting Li
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life SciencesSouth China Normal UniversityGuangzhouChina
| | - Yingzhu Li
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life SciencesSouth China Normal UniversityGuangzhouChina
| | - Haiyan Bai
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life SciencesSouth China Normal UniversityGuangzhouChina
| | - Yanghuan Dai
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life SciencesSouth China Normal UniversityGuangzhouChina
| | - Yanglan Liao
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life SciencesSouth China Normal UniversityGuangzhouChina
| | - Juan Wei
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life SciencesSouth China Normal UniversityGuangzhouChina
| | - Wenjin Shen
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life SciencesSouth China Normal UniversityGuangzhouChina
| | - Binglian Zheng
- State Key Laboratory of Genetic Engineering, Ministry of Education Key Laboratory of Biodiversity Sciences and Ecological Engineering, Institute of Plant Biology, School of Life SciencesFudan UniversityShanghaiChina
| | - Zhonghui Zhang
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life SciencesSouth China Normal UniversityGuangzhouChina
| | - Caiji Gao
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life SciencesSouth China Normal UniversityGuangzhouChina
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Li X, Liao J, Bai H, Bei J, Li K, Luo M, Shen W, Yang C, Gao C. Arabidopsis flowering integrator SOC1 transcriptionally regulates autophagy in response to long-term carbon starvation. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:6589-6599. [PMID: 35852462 DOI: 10.1093/jxb/erac298] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 07/02/2022] [Indexed: 06/15/2023]
Abstract
Autophagy is a highly conserved, self-digestion process that is essential for plant adaptations to various environmental stresses. Although the core components of autophagy in plants have been well established, the molecular basis for its transcriptional regulation remains to be fully characterized. In this study, we demonstrate that SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 (SOC1), a MADS-box family transcription factor that determines flowering transition in Arabidopsis, functions as a transcriptional repressor of autophagy. EMSAs, ChIP-qPCR assays, and dual-luciferase receptor assays showed that SOC1 can bind to the promoters of ATG4b, ATG7, and ATG18c via the conserved CArG box. qRT-PCR analysis showed that the three ATG genes ATG4b, ATG7, and ATG18c were up-regulated in the soc1-2 mutant. In line with this, the mutant also displayed enhanced autophagy activity, as revealed by increased autophagosome formation and elevated autophagic flux compared with the wild type. More importantly, SOC1 negatively affected the tolerance of plants to long-term carbon starvation, and this process requires a functional autophagy pathway. Finally, we found that SOC1 was repressed upon carbon starvation at both the transcriptional and protein levels. Overall, our study not only uncovers an important transcriptional mechanism that contributes to the regulation of plant autophagy in response to nutrient starvation, but also highlights novel cellular functions of the flowering integrator SOC1.
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Affiliation(s)
- Xibao Li
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Jun Liao
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Haiyan Bai
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Jieying Bei
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Kailin Li
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Ming Luo
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Wenjin Shen
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Chao Yang
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Caiji Gao
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
- MOE & Guangdong Provincial Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, China
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Li H, Wei J, Liao Y, Cheng X, Yang S, Zhuang X, Zhang Z, Shen W, Gao C. MLKs kinases phosphorylate the ESCRT component FREE1 to suppress abscisic acid sensitivity of seedling establishment. PLANT, CELL & ENVIRONMENT 2022; 45:2004-2018. [PMID: 35445753 DOI: 10.1111/pce.14336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 03/27/2022] [Accepted: 04/06/2022] [Indexed: 06/14/2023]
Abstract
The FYVE domain protein required for endosomal sorting 1 (FREE1), which was previously identified as a plant-specific component of the endosomal sorting complex required for transport machinery, plays an essential role in endosomal trafficking. Moreover, FREE1 also functions as an important negative regulator in abscisic acid (ABA) signalling. Multiple phosphorylations and ubiquitination sites have been identified in FREE1, hence unveiling the factors involved in posttranslational regulation of FREE1 is critical for comprehensively understanding FREE1-related regulatory networks during plant growth. Here, we demonstrate that plant-specific casein kinase I members MUT9-like kinases 1-4 (MLKs 1-4)/Arabidopsis EL1-like 1-4 interact with and phosphorylate FREE1 at serine residue S582, thereby modulating the nuclear accumulation of FREE1. Consequently, mutation of S582 to non-phosphorylable residue results in reduced nuclear localization of FREE1 and enhanced ABA response. In addition, mlk123 and mlk134 triple mutants accumulate less FREE1 in the nucleus and display hypersensitive responses to ABA treatment, whereas overexpression of the nuclear-localized FREE1 can restore the ABA sensitivity of seedling establishment in mlks triple mutants. Collectively, our study demonstrates a previously unidentified function of MLKs in attenuating ABA signalling in the nucleus by regulating the phosphorylation and nuclear accumulation of FREE1.
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Affiliation(s)
- Hongbo Li
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Juan Wei
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Yanglan Liao
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Xiaoling Cheng
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Shuhong Yang
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Xiaohong Zhuang
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Zhonghui Zhang
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Wenjin Shen
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Caiji Gao
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
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Magen S, Seybold H, Laloum D, Avin-Wittenberg T. Metabolism and autophagy in plants - A perfect match. FEBS Lett 2022; 596:2133-2151. [PMID: 35470431 DOI: 10.1002/1873-3468.14359] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 04/19/2022] [Accepted: 04/20/2022] [Indexed: 01/18/2023]
Abstract
Autophagy is a eukaryotic cellular transport mechanism that delivers intracellular macromolecules, proteins, and even organelles to a lytic organelle (vacuole in yeast and plants/lysosome in animals) for degradation and nutrient recycling. The process is mediated by highly conserved Autophagy-Related (ATG) proteins. In plants, autophagy maintains cellular homeostasis under favorable conditions, guaranteeing normal plant growth and fitness. Severe stress such as nutrient starvation and plant senescence further induce it, thus ensuring plant survival under unfavorable conditions by providing nutrients through the removal of damaged or aged proteins, or organelles. In this article, we examine the interplay between metabolism and autophagy, focusing on the different aspects of this reciprocal relationship. We show that autophagy has a strong influence on a range of metabolic processes, whereas, at the same time, even single metabolites can activate autophagy. We highlight the involvement of ATG genes in metabolism, examine the role of the macronutrients carbon and nitrogen, as well as various micronutrients, and take a closer look at how the interaction between autophagy and metabolism impacts on plant phenotypes and yield.
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Affiliation(s)
- Sahar Magen
- Department of Plant and Environmental Sciences, Alexander Silberman Institute of Life Sciences, the Hebrew University of Jerusalem, Israel
| | - Heike Seybold
- Department of Plant and Environmental Sciences, Alexander Silberman Institute of Life Sciences, the Hebrew University of Jerusalem, Israel
| | - Daniel Laloum
- Department of Plant and Environmental Sciences, Alexander Silberman Institute of Life Sciences, the Hebrew University of Jerusalem, Israel
| | - Tamar Avin-Wittenberg
- Department of Plant and Environmental Sciences, Alexander Silberman Institute of Life Sciences, the Hebrew University of Jerusalem, Israel
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Shedding Light on the Role of Phosphorylation in Plant Autophagy. FEBS Lett 2022; 596:2172-2185. [DOI: 10.1002/1873-3468.14352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/30/2022] [Accepted: 04/04/2022] [Indexed: 11/07/2022]
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