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Smailov B, Alybayev S, Smekenov I, Mursalimov A, Saparbaev M, Sarbassov D, Bissenbaev A. Wheat Germination Is Dependent on Plant Target of Rapamycin Signaling. Front Cell Dev Biol 2020; 8:606685. [PMID: 33330509 PMCID: PMC7719826 DOI: 10.3389/fcell.2020.606685] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 10/21/2020] [Indexed: 12/21/2022] Open
Abstract
Germination is a process of seed sprouting that facilitates embryo growth. The breakdown of reserved starch in the endosperm into simple sugars is essential for seed germination and subsequent seedling growth. At the early stage of germination, gibberellic acid (GA) activates transcription factor GAMYB to promote de novo synthesis of isoforms of α-amylase in the aleurone layer and scutellar epithelium of the embryo. Here, we demonstrate that wheat germination is regulated by plant target of rapamycin (TOR) signaling. TOR is a central component of the essential-nutrient–dependent pathway controlling cell growth in all eukaryotes. It is known that rapamycin, a highly specific allosteric inhibitor of TOR, is effective in yeast and animal cells but ineffective in most of higher plants likely owing to structural differences in ubiquitous rapamycin receptor FKBP12. The action of rapamycin on wheat growth has not been studied. Our data show that rapamycin inhibits germination of wheat seeds and of their isolated embryos in a dose-dependent manner. The involvement of Triticum aestivum TOR (TaTOR) in wheat germination was consistent with the suppression of wheat embryo growth by specific inhibitors of the TOR kinase: pp242 or torin1. Rapamycin or torin1 interfered with GA function in germination because of a potent inhibitory effect on α-amylase and GAMYB gene expression. The TOR inhibitors selectively targeted the GA-dependent gene expression, whereas expression of the abscisic acid-dependent ABI5 gene was not affected by either rapamycin or torin1. To determine whether the TaTOR kinase activation takes place during wheat germination, we examined phosphorylation of a ribosomal protein, T. aestivum S6 kinase 1 (TaS6K1; a substrate of TOR). The phosphorylation of serine 467 (S467) in a hydrophobic motif on TaS6K1 was induced in a process of germination triggered by GA. Moreover, the germination-induced phosphorylation of TaS6K1 on S467 was dependent on TaTOR and was inhibited by rapamycin or torin1. Besides, a gibberellin biosynthesis inhibitor (paclobutrazol; PBZ) blocked not only α-amylase gene expression but also TaS6K1 phosphorylation in wheat embryos. Thus, a hormonal action of GA turns on the synthesis of α-amylase in wheat germination via activation of the TaTOR–S6K1 signaling pathway.
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Affiliation(s)
- Bauyrzhan Smailov
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan.,Scientific Research Institute of Biology and Biotechnology Problems, Al-Farabi Kazakh National University, Almaty, Kazakhstan
| | - Sanzhar Alybayev
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan.,Scientific Research Institute of Biology and Biotechnology Problems, Al-Farabi Kazakh National University, Almaty, Kazakhstan
| | - Izat Smekenov
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan.,Scientific Research Institute of Biology and Biotechnology Problems, Al-Farabi Kazakh National University, Almaty, Kazakhstan
| | - Aibek Mursalimov
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan.,Scientific Research Institute of Biology and Biotechnology Problems, Al-Farabi Kazakh National University, Almaty, Kazakhstan
| | - Murat Saparbaev
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan.,Groupe «Mechanisms of DNA Repair and Carcinogenesis», Equipe Labellisée LIGUE 2016, CNRS UMR 9019, Université Paris-Sud, Gustave Roussy Cancer Campus, Villejuif, France
| | - Dos Sarbassov
- Department of Biology, Nazarbayev University, Nur-Sultan, Kazakhstan
| | - Amangeldy Bissenbaev
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan.,Scientific Research Institute of Biology and Biotechnology Problems, Al-Farabi Kazakh National University, Almaty, Kazakhstan
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Park CS, Choi J, Seong MK, Hong SE, Kim JS, Park IC, Seol H, Noh WC, Kim HA. pS6K1 as an efficacy marker of GnRH agonist with premenopausal breast cancer. Endocr Connect 2019; 8:863-869. [PMID: 31252399 PMCID: PMC6599072 DOI: 10.1530/ec-19-0101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 06/05/2019] [Indexed: 11/10/2022]
Abstract
Estradiol is a key factor for tumorigenesis and prognosis of hormone receptor-positive breast cancer. Adipocytes are one source of estradiol in patients with breast cancer. Recent studies have shown that phosphorylated ribosomal protein S6 kinase-1 plays a critical role in adipogenesis. Therefore, estrogen depletion therapy might have beneficial effects in phosphorylated ribosomal protein S6 kinase-1-positive breast cancer. This study was conducted to evaluate the value of phosphorylated ribosomal protein S6 kinase-1 as a marker for gonadotropin-releasing hormone agonist treatment, a form of estrogen depletion therapy, for premenopausal patients with HR-positive, human epidermal growth factor receptor 2-negative breast cancer. We reviewed the medical records of 296 premenopausal patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative primary invasive breast cancer treated between 2008 and 2015. Phosphorylated ribosomal protein S6 kinase-1 positivity was defined by immunohistochemical staining scores of 1+, 2+ and 3+, whereas a score of 0 was considered negative. Phosphorylated ribosomal protein S6 kinase-1-positive tumors were found in 74.0% of the patients. In the phosphorylated ribosomal protein S6 kinase-1-positive group, disease-free survival of patients treated with a gonadotropin-releasing hormone agonist was significantly longer than that of patients treated without a gonadotropin-releasing hormone agonist (mean 106.7 months vs mean 91.1 months, P = 0.018). Phosphorylated ribosomal protein S6 kinase-1 is a potential biomarker for predicting the efficacy of gonadotropin-releasing hormone agonist therapy in premenopausal patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative breast cancer.
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Affiliation(s)
- Chan Sub Park
- Department of Breast and Thyroid Surgery, Kyungpook National University Chilgok Hospital, Buk-gu, Daegu, Republic of Korea
| | - Jihye Choi
- Department of General Surgery, National Medical Center, Jung-gu, Seoul, Republic of Korea
| | - Min-Ki Seong
- Department of Surgery, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, Nowon-gu, Seoul, Republic of Korea
| | - Sung-Eun Hong
- Radiation Medicine Clinical Research Division, Korea Institute of Radiological and Medical Sciences, Nowon-gu, Seoul, Republic of Korea
| | - Jae-Sung Kim
- Radiation Medicine Clinical Research Division, Korea Institute of Radiological and Medical Sciences, Nowon-gu, Seoul, Republic of Korea
| | - In-Chul Park
- Division of Fusion Radiology Research, Korea Institute of Radiological and Medical Sciences, Nowon-gu, Seoul, Republic of Korea
| | - Hyesil Seol
- Department of Pathology, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, Nowon-gu, Seoul, Republic of Korea
| | - Woo Chul Noh
- Department of Surgery, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, Nowon-gu, Seoul, Republic of Korea
| | - Hyun-Ah Kim
- Department of Surgery, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, Nowon-gu, Seoul, Republic of Korea
- Correspondence should be addressed to H-A Kim:
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