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How phosphorylation impacts intrinsically disordered proteins and their function. Essays Biochem 2022; 66:901-913. [PMID: 36350035 PMCID: PMC9760426 DOI: 10.1042/ebc20220060] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/14/2022] [Accepted: 10/17/2022] [Indexed: 11/10/2022]
Abstract
Phosphorylation is the most common post-translational modification (PTM) in eukaryotes, occurring particularly frequently in intrinsically disordered proteins (IDPs). These proteins are highly flexible and dynamic by nature. Thus, it is intriguing that the addition of a single phosphoryl group to a disordered chain can impact its function so dramatically. Furthermore, as many IDPs carry multiple phosphorylation sites, the number of possible states increases, enabling larger complexities and novel mechanisms. Although a chemically simple and well-understood process, the impact of phosphorylation on the conformational ensemble and molecular function of IDPs, not to mention biological output, is highly complex and diverse. Since the discovery of the first phosphorylation site in proteins 75 years ago, we have come to a much better understanding of how this PTM works, but with the diversity of IDPs and their capacity for carrying multiple phosphoryl groups, the complexity grows. In this Essay, we highlight some of the basic effects of IDP phosphorylation, allowing it to serve as starting point when embarking on studies into this topic. We further describe how recent complex cases of multisite phosphorylation of IDPs have been instrumental in widening our view on the effect of protein phosphorylation. Finally, we put forward perspectives on the phosphorylation of IDPs, both in relation to disease and in context of other PTMs; areas where deep insight remains to be uncovered.
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Yu Y, Portolés S, Ren Y, Sun G, Wang XF, Zhang H, Guo S. The key clock component ZEITLUPE (ZTL) negatively regulates ABA signaling by degradation of CHLH in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2022; 13:995907. [PMID: 36176682 PMCID: PMC9513469 DOI: 10.3389/fpls.2022.995907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Accepted: 08/18/2022] [Indexed: 06/16/2023]
Abstract
Ubiquitination-mediated protein degradation plays important roles in ABA signal transduction and delivering responses to chloroplast stress signals in plants, but additional E3 ligases of protein ubiquitination remain to be identified to understand the complex signaling network. Here we reported that ZEITLUPE (ZTL), an F-box protein, negatively regulates abscisic acid (ABA) signaling during ABA-inhibited early seedling growth and ABA-induced stomatal closure in Arabidopsis thaliana. Using molecular biology and biochemistry approaches, we demonstrated that ZTL interacts with and ubiquitinates its substrate, CHLH/ABAR (Mg-chelatase H subunit/putative ABA receptor), to modulate CHLH stability via the 26S proteasome pathway. CHLH acts genetically downstream of ZTL in ABA and drought stress signaling. Interestingly, ABA conversely induces ZTL phosphorylation, and high levels of ABA also induce CHLH proteasomal degradation, implying that phosphorylated ZTL protein may enhance the affinity to CHLH, leading to the increased degradation of CHLH after ABA treatment. Taken together, our results revealed a possible mechanism of reciprocal regulation between ABA signaling and the circadian clock, which is thought to be essential for plant fitness and survival.
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Affiliation(s)
- Yongtao Yu
- National Watermelon and Melon Improvement Center, Beijing Academy of Agriculture and Forestry Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing, China
| | - Sergi Portolés
- MOE Key Lab of Bioinformatics, Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yi Ren
- National Watermelon and Melon Improvement Center, Beijing Academy of Agriculture and Forestry Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing, China
| | - Guangyu Sun
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Sciences, Northeast Forestry University, Harbin, Heilongjiang, China
| | - Xiao-Fang Wang
- MOE Key Lab of Bioinformatics, Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Huihui Zhang
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Sciences, Northeast Forestry University, Harbin, Heilongjiang, China
| | - Shaogui Guo
- National Watermelon and Melon Improvement Center, Beijing Academy of Agriculture and Forestry Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing, China
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Markandran K, Xuan JVLE, Yu H, Shun LM, Ferenczi MA. Mn 2+ -Phos-Tag Polyacrylamide for the Quantification of Protein Phosphorylation Levels. Curr Protoc 2021; 1:e221. [PMID: 34411463 DOI: 10.1002/cpz1.221] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This paper provides a guideline for optimizing and utilizing Mn2+ Phos-tag gel technology to separate phosphorylated proteins from their unphosphorylated counterparts. It provides key insights into methods for careful sample preparation and experimental directions for determining the appropriate Phos-tag gel compositions and electrophoresis and western blotting conditions. This protocol has been used to successfully resolve proteins extracted from cardiac and skeletal muscles. The guidelines can be extended for optimizing protocols to resolve proteins from other cells or tissue sources. With this, phosphoproteomics and the elucidation of underlying mechanisms of disease progression can be accelerated. © 2021 The Authors. Current Protocols published by Wiley Periodicals LLC.
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Affiliation(s)
- Kasturi Markandran
- Laboratory of Muscle and Cardiac Biophysics, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Jane Vanetta Lee En Xuan
- Laboratory of Muscle and Cardiac Biophysics, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Haiyang Yu
- Laboratory of Muscle and Cardiac Biophysics, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.,WuXi Biologics, Wuxi, Jiangsu, China
| | - Lim Meng Shun
- Laboratory of Muscle and Cardiac Biophysics, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Michael A Ferenczi
- Laboratory of Muscle and Cardiac Biophysics, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.,Brunel Medical School, Brunel University London, Uxbridge, UK
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Vega A, Fredes I, O'Brien J, Shen Z, Ötvös K, Abualia R, Benkova E, Briggs SP, Gutiérrez RA. Nitrate triggered phosphoproteome changes and a PIN2 phosphosite modulating root system architecture. EMBO Rep 2021; 22:e51813. [PMID: 34357701 PMCID: PMC8447600 DOI: 10.15252/embr.202051813] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 05/13/2021] [Accepted: 06/23/2021] [Indexed: 01/04/2023] Open
Abstract
Nitrate commands genome‐wide gene expression changes that impact metabolism, physiology, plant growth, and development. In an effort to identify new components involved in nitrate responses in plants, we analyze the Arabidopsis thaliana root phosphoproteome in response to nitrate treatments via liquid chromatography coupled to tandem mass spectrometry. 176 phosphoproteins show significant changes at 5 or 20 min after nitrate treatments. Proteins identified by 5 min include signaling components such as kinases or transcription factors. In contrast, by 20 min, proteins identified were associated with transporter activity or hormone metabolism functions, among others. The phosphorylation profile of NITRATE TRANSPORTER 1.1 (NRT1.1) mutant plants was significantly altered as compared to wild‐type plants, confirming its key role in nitrate signaling pathways that involves phosphorylation changes. Integrative bioinformatics analysis highlights auxin transport as an important mechanism modulated by nitrate signaling at the post‐translational level. We validated a new phosphorylation site in PIN2 and provide evidence that it functions in primary and lateral root growth responses to nitrate.
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Affiliation(s)
- Andrea Vega
- Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Santiago, Chile.,FONDAP Center for Genome Regulation, ANID - Millennium Science Initiative Program - Millennium Institute for Integrative Biology (iBio), Santiago, Chile
| | - Isabel Fredes
- Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Santiago, Chile.,FONDAP Center for Genome Regulation, ANID - Millennium Science Initiative Program - Millennium Institute for Integrative Biology (iBio), Santiago, Chile
| | - José O'Brien
- Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Santiago, Chile.,FONDAP Center for Genome Regulation, ANID - Millennium Science Initiative Program - Millennium Institute for Integrative Biology (iBio), Santiago, Chile.,Departamento de Fruticultura y Enología, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Zhouxin Shen
- Cell and Developmental Biology, University of California San Diego. San Diego, CA, USA
| | - Krisztina Ötvös
- Institute of Science and Technology (IST) Austria, Klosterneuburg, Austria.,Bioresources Unit, Center for Health & Bioresources, AIT Austrian Institute of Technology GmbH, Tulln, Austria
| | - Rashed Abualia
- Institute of Science and Technology (IST) Austria, Klosterneuburg, Austria
| | - Eva Benkova
- Institute of Science and Technology (IST) Austria, Klosterneuburg, Austria
| | - Steven P Briggs
- Cell and Developmental Biology, University of California San Diego. San Diego, CA, USA
| | - Rodrigo A Gutiérrez
- Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Santiago, Chile.,FONDAP Center for Genome Regulation, ANID - Millennium Science Initiative Program - Millennium Institute for Integrative Biology (iBio), Santiago, Chile
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Takáč T, Šamaj J. Advantages and limitations of shot-gun proteomic analyses on Arabidopsis plants with altered MAPK signaling. FRONTIERS IN PLANT SCIENCE 2015; 6:107. [PMID: 25763005 PMCID: PMC4340173 DOI: 10.3389/fpls.2015.00107] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 02/09/2015] [Indexed: 05/27/2023]
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Regulation and function of phosphorylation on VP8, the major tegument protein of bovine herpesvirus 1. J Virol 2015; 89:4598-611. [PMID: 25673708 DOI: 10.1128/jvi.03180-14] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
UNLABELLED The major tegument protein of bovine herpesvirus 1 (BoHV-1), VP8, is essential for virus replication in cattle. VP8 is phosphorylated in vitro by casein kinase 2 (CK2) and BoHV-1 unique short protein 3 (US3). In this study, VP8 was found to be phosphorylated in both transfected and infected cells but was detected as a nonphosphorylated form in mature virions. This suggests that phosphorylation of VP8 is strictly controlled during different stages of the viral life cycle. The regulation and function of VP8 phosphorylation by US3 and CK2 were further analyzed. An in vitro kinase assay, site-directed mutagenesis, and liquid chromatography-mass spectrometry were used to identify the active sites for US3 and CK2. The two kinases phosphorylate VP8 at different sites, resulting in distinct phosphopeptide patterns. S(16) is a primary phosphoreceptor for US3, and it subsequently triggers phosphorylation at S(32). CK2 has multiple active sites, among which T(107) appears to be the preferred residue. Additionally, CK2 consensus motifs in the N terminus of VP8 are essential for phosphorylation. Based on these results, a nonphosphorylated VP8 mutant was constructed and used for further studies. In transfected cells phosphorylation was not required for nuclear localization of VP8. Phosphorylated VP8 appeared to recruit promyelocytic leukemia (PML) protein and to remodel the distribution of PML in the nucleus; however, PML protein did not show an association with nonphosphorylated VP8. This suggests that VP8 plays a role in resisting PML-related host antiviral defenses by redistributing PML protein and that this function depends on the phosphorylation of VP8. IMPORTANCE The progression of VP8 phosphorylation over time and its function in BoHV-1 replication have not been characterized. This study demonstrates that activation of S(16) initiates further phosphorylation at S(32) by US3. Additionally, VP8 is phosphorylated by CK2 at several residues, with T(107) having the highest level of phosphorylation. Evidence for a difference in the phosphorylation status of VP8 in host cells and mature virus is presented for the first time. Phosphorylation was found to be a critical modification, which enables VP8 to attract and to redistribute PML protein in the nucleus. This might promote viral replication through interference with a PML-mediated antiviral defense. This study provides new insights into the regulation of VP8 phosphorylation and suggests a novel, phosphorylation-dependent function for VP8 in the life cycle of BoHV-1, which is important in view of the fact that VP8 is essential for virus replication in vivo.
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Bekešová S, Komis G, Křenek P, Vyplelová P, Ovečka M, Luptovčiak I, Illés P, Kuchařová A, Šamaj J. Monitoring protein phosphorylation by acrylamide pendant Phos-Tag™ in various plants. FRONTIERS IN PLANT SCIENCE 2015; 6:336. [PMID: 26029234 PMCID: PMC4429547 DOI: 10.3389/fpls.2015.00336] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 04/28/2015] [Indexed: 05/20/2023]
Abstract
The aim of the present study is to rationalize acrylamide pendant Phos-Tag™ in-gel discrimination of phosphorylated and non-phosphorylated plant protein species with standard immunoblot analysis, and optimize sample preparation, efficient electrophoretic separation and transfer. We tested variants of the method including extraction buffers suitable for preservation of phosphorylated protein species in crude extracts from plants and we addressed the importance of the cation (Mn(2+) or Zn(2+)) used in the gel recipe for efficient transfer to PVDF membranes for further immunoblot analysis. We demonstrate the monitoring of Medicago sativa stress-induced mitogen activated protein kinase (SIMK) in stress-treated wild type plants and transgenic SIMKK RNAi line. We further show the hyperosmotically-induced phosphorylation of the previously uncharacterized HvMPK4 of barley. The method is validated using inducible phosphorylation of barley and wheat α-tubulin and of Arabidopsis MPK6. Acrylamide pendant Phos-Tag™offers a flexible tool for studying protein phosphorylation in crops and Arabidopsis circumventing radioactive labeling and the use of phosphorylation specific antibodies.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Jozef Šamaj
- *Correspondence: Jozef Šamaj, Department of Cell Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University Olomouc, Šlechtitelů 27, Olomouc 783 71, Czech Republic
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