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Sanchez NA, Kallweit LM, Trnka MJ, Clemmer CL, Al-Sady B. Heterodimerization of H3K9 histone methyltransferases G9a and GLP activates methyl reading and writing capabilities. J Biol Chem 2021; 297:101276. [PMID: 34619147 PMCID: PMC8564726 DOI: 10.1016/j.jbc.2021.101276] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 09/27/2021] [Accepted: 09/30/2021] [Indexed: 11/27/2022] Open
Abstract
Unique among metazoan repressive histone methyltransferases, G9a and GLP, which chiefly target histone 3 lysine 9 (H3K9), require dimerization for productive H3K9 mono (me1)- and dimethylation (me2) in vivo. Intriguingly, even though each enzyme can independently methylate H3K9, the predominant active form in vivo is a heterodimer of G9a and GLP. How dimerization influences the central H3K9 methyl binding ("reading") and deposition ("writing") activity of G9a and GLP and why heterodimerization is essential in vivo remains opaque. Here, we examine the H3K9me "reading" and "writing" activities of defined, recombinantly produced homo- and heterodimers of G9a and GLP. We find that both reading and writing are significantly enhanced in the heterodimer. Compared with the homodimers, the heterodimer has higher recognition of H3K9me2, and a striking ∼10-fold increased turnover rate for nucleosomal substrates under multiple turnover conditions, which is not evident on histone tail peptide substrates. Cross-linking Mass Spectrometry suggests that differences between the homodimers and the unique activity of the heterodimer may be encoded in altered ground state conformations, as each dimer displays different domain contacts. Our results indicate that heterodimerization may be required to relieve autoinhibition of H3K9me reading and chromatin methylation evident in G9a and GLP homodimers. Relieving this inhibition may be particularly important in early differentiation when large tracts of H3K9me2 are typically deposited by G9a-GLP, which may require a more active form of the enzyme.
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Affiliation(s)
- Nicholas A Sanchez
- Department of Microbiology & Immunology, George Williams Hooper Foundation, University of California San Francisco, San Francisco, California, USA; TETRAD Graduate Program, University of California San Francisco, San Francisco, California, USA
| | - Lena M Kallweit
- Department of Microbiology & Immunology, George Williams Hooper Foundation, University of California San Francisco, San Francisco, California, USA
| | - Michael J Trnka
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, USA
| | - Charles L Clemmer
- Department of Microbiology & Immunology, George Williams Hooper Foundation, University of California San Francisco, San Francisco, California, USA
| | - Bassem Al-Sady
- Department of Microbiology & Immunology, George Williams Hooper Foundation, University of California San Francisco, San Francisco, California, USA.
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Greenstein R, Barrales RR, Sanchez NA, Bisanz JE, Braun S, Al-Sady B. Erratum: Set1/COMPASS repels heterochromatin invasion at euchromatic sites by disrupting Suv39/Clr4 activity and nucleosome stability. Genes Dev 2020; 34:1106. [DOI: 10.1101/gad.342006.120] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Greenstein RA, Barrales RR, Sanchez NA, Bisanz JE, Braun S, Al-Sady B. Set1/COMPASS repels heterochromatin invasion at euchromatic sites by disrupting Suv39/Clr4 activity and nucleosome stability. Genes Dev 2019; 34:99-117. [PMID: 31805521 PMCID: PMC6938669 DOI: 10.1101/gad.328468.119] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [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: 05/08/2019] [Accepted: 10/30/2019] [Indexed: 12/27/2022]
Abstract
In this study, Greenstein et al. set out to define the spatial encoding signals within euchromatin that act to limit heterochromatin spreading. Using molecular and cell-based assays in fission yeast, the authors report that heterochromatin repulsion is locally encoded by Set1/COMPASS on certain actively transcribed genes and that this protective role is most prominent at heterochromatin islands, small domains interspersed in euchromatin that regulate cell fate specifiers. Protection of euchromatin from invasion by gene-repressive heterochromatin is critical for cellular health and viability. In addition to constitutive loci such as pericentromeres and subtelomeres, heterochromatin can be found interspersed in gene-rich euchromatin, where it regulates gene expression pertinent to cell fate. While heterochromatin and euchromatin are globally poised for mutual antagonism, the mechanisms underlying precise spatial encoding of heterochromatin containment within euchromatic sites remain opaque. We investigated ectopic heterochromatin invasion by manipulating the fission yeast mating type locus boundary using a single-cell spreading reporter system. We found that heterochromatin repulsion is locally encoded by Set1/COMPASS on certain actively transcribed genes and that this protective role is most prominent at heterochromatin islands, small domains interspersed in euchromatin that regulate cell fate specifiers. Sensitivity to invasion by heterochromatin, surprisingly, is not dependent on Set1 altering overall gene expression levels. Rather, the gene-protective effect is strictly dependent on Set1's catalytic activity. H3K4 methylation, the Set1 product, antagonizes spreading in two ways: directly inhibiting catalysis by Suv39/Clr4 and locally disrupting nucleosome stability. Taken together, these results describe a mechanism for spatial encoding of euchromatic signals that repel heterochromatin invasion.
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Affiliation(s)
- R A Greenstein
- Department of Microbiology and Immunology, George Williams Hooper Foundation, University of California at San Francisco, San Francisco, California 94143, USA.,TETRAD Graduate Program, University of California at San Francisco, San Francisco, California 94143, USA
| | - Ramon R Barrales
- Department of Physiological Chemistry, Biomedical Center (BMC), Ludwig Maximilians University of Munich, 82152 Martinsried, Germany.,International Max Planck Research School for Molecular and Cellular Life Sciences, 82152 Martinsried, Germany
| | - Nicholas A Sanchez
- Department of Microbiology and Immunology, George Williams Hooper Foundation, University of California at San Francisco, San Francisco, California 94143, USA.,TETRAD Graduate Program, University of California at San Francisco, San Francisco, California 94143, USA
| | - Jordan E Bisanz
- Department of Microbiology and Immunology, George Williams Hooper Foundation, University of California at San Francisco, San Francisco, California 94143, USA
| | - Sigurd Braun
- Department of Physiological Chemistry, Biomedical Center (BMC), Ludwig Maximilians University of Munich, 82152 Martinsried, Germany.,International Max Planck Research School for Molecular and Cellular Life Sciences, 82152 Martinsried, Germany
| | - Bassem Al-Sady
- Department of Microbiology and Immunology, George Williams Hooper Foundation, University of California at San Francisco, San Francisco, California 94143, USA
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Valkevich E, Sanchez NA, Ge Y, Strieter ER. Middle-down mass spectrometry enables characterization of branched ubiquitin chains. Biochemistry 2014; 53:4979-89. [PMID: 25023374 PMCID: PMC4372068 DOI: 10.1021/bi5006305] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 07/09/2014] [Indexed: 12/22/2022]
Abstract
Protein ubiquitylation, one of the most prevalent post-translational modifications in eukaryotes, is involved in regulating nearly every cellular signaling pathway. The vast functional range of ubiquitylation has largely been attributed to the formation of a diverse array of polymeric ubiquitin (polyUb) chains. Methods that enable the characterization of these diverse chains are necessary to fully understand how differences in structure relate to function. Here, we describe a method for the detection of enzymatically derived branched polyUb conjugates in which a single Ub subunit is modified by two Ub molecules at distinct lysine residues. Using a middle-down mass spectrometry approach in which restricted trypsin-mediated digestion is coupled with mass spectrometric analysis, we characterize the polyUb chains produced by bacterial effector E3 ligases NleL (non-Lee-encoded effector ligase from enterohemorrhagic Escherichia coli O157:H7) and IpaH9.8 (from Shigella flexneri). Because Ub is largely intact after minimal trypsinolysis, multiple modifications on a single Ub moiety can be detected. Analysis of NleL- and IpaH9.8-derived polyUb chains reveals branch points are present in approximately 10% of the overall chain population. When unanchored, well-defined polyUb chains are added to reaction mixtures containing NleL, longer chains are more likely to be modified internally, forming branch points rather than extending from the end of the chain. These results suggest that middle-down mass spectrometry can be used to assess the extent to which branched polyUb chains are formed by various enzymatic systems and potentially evaluate the presence of these atypical conjugates in cell and tissue extracts.
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Affiliation(s)
- Ellen
M. Valkevich
- Department
of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Nicholas A. Sanchez
- Department
of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Ying Ge
- Department
of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
- Department
of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin—Madison, 1300 University Avenue, Madison, Wisconsin 53706, United States
| | - Eric R. Strieter
- Department
of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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Abstract
This qualitative research investigated the perception of mothers regarding hospital support after perinatal loss. Twelve in-depth interviews demonstrated that the mothers recalled the circumstances of the loss. Most identified the hospital's support services and made comments on aspects of hospital support as influential in grief recovery. Most interviewees considered themselves somewhat recovered from the loss.
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Affiliation(s)
- N A Sanchez
- N ancy A nne S anchez is the Perinatal Education Coordinator at Lucile Packard Children's Hospital at Stanford University Medical Center in Palo Alto, California
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Valkevich EM, Guenette RG, Sanchez NA, Chen YC, Ge Y, Strieter ER. Forging isopeptide bonds using thiol-ene chemistry: site-specific coupling of ubiquitin molecules for studying the activity of isopeptidases. J Am Chem Soc 2012; 134:6916-9. [PMID: 22497214 DOI: 10.1021/ja300500a] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Chemical methods for modifying proteins can enable studies aimed at uncovering biochemical function. Herein, we describe the use of thiol-ene coupling (TEC) chemistry to report on the function of branched (also referred to as forked) ubiquitin trimers. We show how site-specific isopeptide (Nε-Gly-L-homothiaLys) bonds are forged between two molecules of Ub, demonstrating the power of TEC in protein conjugation. Moreover, we demonstrate that the Nε-Gly-L-homothiaLys isopeptide bond is processed to a similar extent by deubiquitinases (DUBs) as that of a native Nε-Gly-L-Lys isopeptide bond, thereby establishing the utility of TEC in the generation of Ub-Ub linkages. TEC is then applied to the synthesis of branched Ub trimers. Interrogation of these branched derivatives with DUBs reveals that the relative orientation of the two Ub units has a dramatic impact on how they are hydrolyzed. In particular, cleavage of K48C-linkages is suppressed when the central Ub unit is also conjugated through K6C, whereas cleavage proceeds normally when the central unit is conjugated through either K11C or K63C. The results of this work presage a role for branched polymeric Ub chains in regulating linkage-selective interactions.
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Affiliation(s)
- Ellen M Valkevich
- Department of Chemistry, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin 53706-1322, USA
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Lee G, Seckinger D, Chan MC, Embi A, Stobbe D, Thomson RV, Sanchez NA, Ikeda RM, Reis RL, Mason DT. Potential complications of coronary laser angioplasty. Am Heart J 1984; 108:1577-9. [PMID: 6239531 DOI: 10.1016/0002-8703(84)90719-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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