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Parker HV, Tooley JG, Schaner Tooley CE. Optimizing purification and activity assays of N-terminal methyltransferase complexes. Methods Enzymol 2023; 684:71-111. [PMID: 37230594 PMCID: PMC10619428 DOI: 10.1016/bs.mie.2023.02.001] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
In vitro methyltransferase assays have traditionally been carried out with tritiated S-adenosyl-methionine (SAM) as the methyl donor, as site-specific methylation antibodies are not always available for Western or dot blots and structural requirements of many methyltransferases prohibit the use of peptide substrates in luminescent or colorimetric assays. The discovery of the first N-terminal methyltransferase, METTL11A, has allowed for a second look at non-radioactive in vitro methyltransferase assays, as N-terminal methylation is amenable to antibody production and the limited structural requirements of METTL11A allow for its methylation of peptide substrates. We have used a combination of Western blots and luminescent assays to verify substrates of METTL11A and the two other known N-terminal methyltransferases, METTL11B and METTL13. We have also developed these assays for use beyond substrate identification, showing that METTL11A activity is opposingly regulated by METTL11B and METTL13. Here we provide two methods for non-radioactive characterization of N-terminal methylation, Western blots with full-length recombinant protein substrates and luminescent assays with peptide substrates, and describe how each can be additionally adapted to look at regulatory complexes. We will review the advantages and disadvantages of each method in context with the other types of in vitro methyltransferase assays and discuss why these types of assays could be of general use to the N-terminal modification field.
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Affiliation(s)
- Haley V Parker
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, United States
| | - John G Tooley
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, United States
| | - Christine E Schaner Tooley
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, United States.
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Conner MM, Schaner Tooley CE. Three's a crowd - why did three N-terminal methyltransferases evolve for one job? J Cell Sci 2023; 136:jcs260424. [PMID: 36647772 PMCID: PMC10022744 DOI: 10.1242/jcs.260424] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
N-terminal methylation of the α-amine group (Nα-methylation) is a post-translational modification (PTM) that was discovered over 40 years ago. Although it is not the most abundant of the Nα-PTMs, there are more than 300 predicted substrates of the three known mammalian Nα-methyltransferases, METTL11A and METTL11B (also known as NTMT1 and NTMT2, respectively) and METTL13. Of these ∼300 targets, the bulk are acted upon by METTL11A. Only one substrate is known to be Nα-methylated by METTL13, and METTL11B has no proven in vivo targets or predicted targets that are not also methylated by METTL11A. Given that METTL11A could clearly handle the entire substrate burden of Nα-methylation, it is unclear why three distinct Nα-methyltransferases have evolved. However, recent evidence suggests that many methyltransferases perform important biological functions outside of their catalytic activity, and the Nα-methyltransferases might be part of this emerging group. Here, we describe the distinct expression, localization and physiological roles of each Nα-methyltransferase, and compare these characteristics to other methyltransferases with non-catalytic functions, as well as to methyltransferases with both catalytic and non-catalytic functions, to give a better understanding of the global roles of these proteins. Based on these comparisons, we hypothesize that these three enzymes do not just have one common function but are actually performing three unique jobs in the cell.
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Affiliation(s)
- Meghan M. Conner
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY 14203, USA
| | - Christine E. Schaner Tooley
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY 14203, USA
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Zhang J, Song H, Chen C, Chen L, Dai Y, Sun PH, Zou C, Wang X. Methyltransferase-like protein 11A promotes migration of cervical cancer cells via up-regulating ELK3. Pharmacol Res 2021; 172:105814. [PMID: 34450313 DOI: 10.1016/j.phrs.2021.105814] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Revised: 07/05/2021] [Accepted: 08/11/2021] [Indexed: 12/22/2022]
Abstract
Cervical cancer is one of the common malignancies in women, which is characterized with high invasion and metastatic tendency in its advanced stage. Increasing evidence indicates that methyltransferase-like (METTL) gene family is involved in the progression of various cancers. However, the functional role of methyltransferase-like gene family in cervical cancer remains unclear. In the present study, we found that METTL11A, a member of the methyltransferase-like gene family, was significantly over-expressed in cervical carcinoma by analyzing TCGA database. This finding was further validated in clinical tissue samples. Moreover, ectopic expression of METTL11A in cervical cancer cell lines promoted cell proliferation and migration both in vitro and in vivo. Differential gene expression analysis in the transcriptomic sequencing data indicated that ELK3 was down-regulated in METTL11A-silenced cervical cancer cells, which was further verified at both protein and mRNA levels. Functional experiments identified that METTL11A promoted migration of cervical cancer cells in an ELK3-dependent manner. This study will promote understanding the mechanism of cervical cancer progression and the functional role of methyltransferase-like gene families in cancers.
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Affiliation(s)
- Jinling Zhang
- Department of Gynaecology, The Second Clinical Medical College of Jinan University, Shenzhen People's Hospital, Shenzhen, China
| | - Huibin Song
- Department of Clinical Medical Research Center, The 2nd Clinical Medical College (Shenzhen People's Hospital) of Jinan University, The First Affiliated Hospital of Southern University of Science and Technology, Shenzhen, China; Integrated Chinese and Western Medicine Postdoctoral Research Station, Jinan University, Guangzhou, Guangdong, PR China
| | - Chen Chen
- Department of Clinical Medical Research Center, The 2nd Clinical Medical College (Shenzhen People's Hospital) of Jinan University, The First Affiliated Hospital of Southern University of Science and Technology, Shenzhen, China; China-America Cancer Research Institute, Dongguan Key Laboratory of Epigenetics Guangdong Medical University, Dongguan, China
| | - Lipeng Chen
- Department of Clinical Medical Research Center, The 2nd Clinical Medical College (Shenzhen People's Hospital) of Jinan University, The First Affiliated Hospital of Southern University of Science and Technology, Shenzhen, China
| | - Yong Dai
- Department of Clinical Medical Research Center, The 2nd Clinical Medical College (Shenzhen People's Hospital) of Jinan University, The First Affiliated Hospital of Southern University of Science and Technology, Shenzhen, China
| | - Ping-Hui Sun
- Department of Clinical Medical Research Center, The 2nd Clinical Medical College (Shenzhen People's Hospital) of Jinan University, The First Affiliated Hospital of Southern University of Science and Technology, Shenzhen, China
| | - Chang Zou
- Department of Clinical Medical Research Center, The 2nd Clinical Medical College (Shenzhen People's Hospital) of Jinan University, The First Affiliated Hospital of Southern University of Science and Technology, Shenzhen, China; School of Life and Health Sciences, The Chinese University of Hong Kong, Shenzhen, Longgang District, Shenzhen, Guangdong Province 518172, China; Shenzhen Public Service Platform on Tumor Precision Medicine and Molecular Diagnosis, The Second Clinical Medical College of Jinan University, Shenzhen People's Hospital, Shenzhen, China.
| | - Xiaoyu Wang
- Department of Gynaecology, The First Affiliated Hospital of Jinan University, Guangzhou, China.
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