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Bakshi A, Moin M, Gayatri MB, Reddy ABM, Datla R, Madhav MS, Kirti PB. Involvement of Target of Rapamycin (TOR) Signaling in the Regulation of Crosstalk between Ribosomal Protein Small Subunit 6 Kinase-1 (RPS6K-1) and Ribosomal Proteins. PLANTS (BASEL, SWITZERLAND) 2023; 12:176. [PMID: 36616305 PMCID: PMC9824793 DOI: 10.3390/plants12010176] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 12/26/2022] [Accepted: 12/27/2022] [Indexed: 06/17/2023]
Abstract
The target of rapamycin (TOR) protein phosphorylates its downstream effector p70kDa ribosomal protein S6 kinases (S6K1) for ribosome biogenesis and translation initiation in eukaryotes. However, the molecular mechanism of TOR-S6K1-ribosomal protein (RP) signaling is not well understood in plants. In the present study, we report the transcriptional upregulation of ribosomal protein large and small subunit (RPL and RPS) genes in the previously established TOR overexpressing transgenic lines of rice (in Oryza sativa ssp. indica, variety BPT-5204, TR-2.24 and TR-15.1) and of Arabidopsis thaliana (in Col 0 ecotype, ATR-1.4.27 and ATR-3.7.32). The mRNA levels of RP genes from this study were compared with those previously available in transcriptomic datasets on the expression of RPs in relation to TOR inhibitor and in the TOR-RNAi lines of Arabidopsis thaliana. We further analyzed TOR activity, i.e., S6K1 phosphorylation in SALK lines of Arabidopsis with mutation in rpl6, rpl18, rpl23, rpl24 and rps28C, where the rpl18 mutant showed inactivation of S6K1 phosphorylation. We also predicted similar putative Ser/Thr phosphorylation sites for ribosomal S6 kinases (RSKs) in the RPs of Oryza sativa ssp. indica and Arabidopsis thaliana. The findings of this study indicate that the TOR pathway is possibly interlinked in a cyclic manner via the phosphorylation of S6K1 as a modulatory step for the regulation of RP function to switch 'on'/'off' the translational regulation for balanced plant growth.
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Affiliation(s)
- Achala Bakshi
- Indian Institute of Rice Research, Rajendranagar, Hyderabad 500030, Telangana, India
- Global Institute for Food Security, Saskatoon, SK S7N 0W9, Canada
| | - Mazahar Moin
- Indian Institute of Rice Research, Rajendranagar, Hyderabad 500030, Telangana, India
- Agri Biotech Foundation, PJTS Agricultural University Campus, Rajendranagar, Hyderabad 500030, Telangana, India
| | - Meher B. Gayatri
- Department of Animal Biology, University of Hyderabad, Hyderabad 500046, Telangana, India
| | - Aramati B. M. Reddy
- Department of Animal Biology, University of Hyderabad, Hyderabad 500046, Telangana, India
| | - Raju Datla
- Global Institute for Food Security, Saskatoon, SK S7N 0W9, Canada
| | - Maganti S. Madhav
- Indian Institute of Rice Research, Rajendranagar, Hyderabad 500030, Telangana, India
- Central Tobacco Research Institute, Rajahmundry 533105, Andhra Pradesh, India
| | - Pulugurtha B. Kirti
- Agri Biotech Foundation, PJTS Agricultural University Campus, Rajendranagar, Hyderabad 500030, Telangana, India
- Department of Plant Sciences, University of Hyderabad, Hyderabad 500046, Telangana, India
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Tariq K, Luikart BW. Striking a balance: PIP 2 and PIP 3 signaling in neuronal health and disease. EXPLORATION OF NEUROPROTECTIVE THERAPY 2022; 1:86-100. [PMID: 35098253 PMCID: PMC8797975 DOI: 10.37349/ent.2021.00008] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Phosphoinositides are membrane phospholipids involved in a variety of cellular processes like growth, development, metabolism, and transport. This review focuses on the maintenance of cellular homeostasis of phosphatidylinositol 4,5-bisphosphate (PIP2), and phosphatidylinositol 3,4,5-trisphosphate (PIP3). The critical balance of these PIPs is crucial for regulation of neuronal form and function. The activity of PIP2 and PIP3 can be regulated through kinases, phosphatases, phospholipases and cholesterol microdomains. PIP2 and PIP3 carry out their functions either indirectly through their effectors activating integral signaling pathways, or through direct regulation of membrane channels, transporters, and cytoskeletal proteins. Any perturbations to the balance between PIP2 and PIP3 signaling result in neurodevelopmental and neurodegenerative disorders. This review will discuss the upstream modulators and downstream effectors of the PIP2 and PIP3 signaling, in the context of neuronal health and disease.
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Affiliation(s)
- Kamran Tariq
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Bryan W Luikart
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
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Obomighie I, Lapenas K, Murphy BE, Bowles AMC, Bechtold U, Prischi F. The Role of Ribosomal Protein S6 Kinases in Plant Homeostasis. Front Mol Biosci 2021; 8:636560. [PMID: 33778006 PMCID: PMC7988200 DOI: 10.3389/fmolb.2021.636560] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 01/11/2021] [Indexed: 01/11/2023] Open
Abstract
The p70 ribosomal S6 kinase (S6K) family is a group of highly conserved kinases in eukaryotes that regulates cell growth, cell proliferation, and stress response via modulating protein synthesis and ribosomal biogenesis. S6Ks are downstream effectors of the Target of Rapamycin (TOR) pathway, which connects nutrient and energy signaling to growth and homeostasis, under normal and stress conditions. The plant S6K family includes two isoforms, S6K1 and S6K2, which, despite their high level of sequence similarity, have distinct functions and regulation mechanisms. Significant advances on the characterization of human S6Ks have occurred in the past few years, while studies on plant S6Ks are scarce. In this article, we review expression and activation of the two S6K isoforms in plants and we discuss their roles in mediating responses to stresses and developmental cues.
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Affiliation(s)
| | - Kestutis Lapenas
- School of Life Sciences, University of Essex, Colchester, United Kingdom
| | - Billy E Murphy
- School of Life Sciences, University of Essex, Colchester, United Kingdom
| | | | - Ulrike Bechtold
- School of Life Sciences, University of Essex, Colchester, United Kingdom
| | - Filippo Prischi
- School of Life Sciences, University of Essex, Colchester, United Kingdom
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Xu F, Na L, Li Y, Chen L. Roles of the PI3K/AKT/mTOR signalling pathways in neurodegenerative diseases and tumours. Cell Biosci 2020; 10:54. [PMID: 32266056 PMCID: PMC7110906 DOI: 10.1186/s13578-020-00416-0] [Citation(s) in RCA: 356] [Impact Index Per Article: 89.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 03/26/2020] [Indexed: 02/06/2023] Open
Abstract
The PI3 K/AKT/mTOR signalling pathway plays an important role in the regulation of signal transduction and biological processes such as cell proliferation, apoptosis, metabolism and angiogenesis. Compared with those of other signalling pathways, the components of the PI3K/AKT/mTOR signalling pathway are complicated. The regulatory mechanisms and biological functions of the PI3K/AKT/mTOR signalling pathway are important in many human diseases, including ischaemic brain injury, neurodegenerative diseases, and tumours. PI3K/AKT/mTOR signalling pathway inhibitors include single-component and dual inhibitors. Numerous PI3K inhibitors have exhibited good results in preclinical studies, and some have been clinically tested in haematologic malignancies and solid tumours. In this review, we briefly summarize the results of research on the PI3K/AKT/mTOR pathway and discuss the structural composition, activation, communication processes, regulatory mechanisms and biological functions of the PI3K/AKT/mTOR signalling pathway in the pathogenesis of neurodegenerative diseases and tumours.
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Affiliation(s)
- Fei Xu
- Department of Microbiology and Immunology, Shanghai University of Medicine & Health Sciences, 279 Zhouzhu Rd, Shanghai, 201318 China
- Collaborative Innovation Center of Shanghai University of Medicine & Health Sciences, Shanghai, 201318 China
| | - Lixin Na
- Collaborative Innovation Center of Shanghai University of Medicine & Health Sciences, Shanghai, 201318 China
- Department of Inspection and Quarantine, Shanghai University of Medicine & Health Sciences, Shanghai, 201318 China
| | - Yanfei Li
- Department of Inspection and Quarantine, Shanghai University of Medicine & Health Sciences, Shanghai, 201318 China
| | - Linjun Chen
- Department of Inspection and Quarantine, Shanghai University of Medicine & Health Sciences, Shanghai, 201318 China
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