1
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Li J, Purser N, Liwocha J, Scott DC, Byers HA, Steigenberger B, Hill S, Tripathi-Giesgen I, Hinkle T, Hansen FM, Prabu JR, Radhakrishnan SK, Kirkpatrick DS, Reichermeier KM, Schulman BA, Kleiger G. Cullin-RING ligases employ geometrically optimized catalytic partners for substrate targeting. Mol Cell 2024; 84:1304-1320.e16. [PMID: 38382526 PMCID: PMC10997478 DOI: 10.1016/j.molcel.2024.01.022] [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] [Received: 09/13/2023] [Revised: 12/07/2023] [Accepted: 01/25/2024] [Indexed: 02/23/2024]
Abstract
Cullin-RING ligases (CRLs) ubiquitylate specific substrates selected from other cellular proteins. Substrate discrimination and ubiquitin transferase activity were thought to be strictly separated. Substrates are recognized by substrate receptors, such as Fbox or BCbox proteins. Meanwhile, CRLs employ assorted ubiquitin-carrying enzymes (UCEs, which are a collection of E2 and ARIH-family E3s) specialized for either initial substrate ubiquitylation (priming) or forging poly-ubiquitin chains. We discovered specific human CRL-UCE pairings governing substrate priming. The results reveal pairing of CUL2-based CRLs and UBE2R-family UCEs in cells, essential for efficient PROTAC-induced neo-substrate degradation. Despite UBE2R2's intrinsic programming to catalyze poly-ubiquitylation, CUL2 employs this UCE for geometrically precise PROTAC-dependent ubiquitylation of a neo-substrate and for rapid priming of substrates recruited to diverse receptors. Cryo-EM structures illuminate how CUL2-based CRLs engage UBE2R2 to activate substrate ubiquitylation. Thus, pairing with a specific UCE overcomes E2 catalytic limitations to drive substrate ubiquitylation and targeted protein degradation.
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Affiliation(s)
- Jerry Li
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV 89154, USA
| | - Nicholas Purser
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV 89154, USA
| | - Joanna Liwocha
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Daniel C Scott
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Holly A Byers
- Department of Pathology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Barbara Steigenberger
- Mass Spectrometry Core Facility, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Spencer Hill
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV 89154, USA
| | - Ishita Tripathi-Giesgen
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Trent Hinkle
- Genentech, 1 DNA Way, South San Francisco, CA 94080, USA
| | - Fynn M Hansen
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - J Rajan Prabu
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | | | | | | | - Brenda A Schulman
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried 82152, Germany; Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
| | - Gary Kleiger
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV 89154, USA; Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried 82152, Germany.
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2
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Liwocha J, Li J, Purser N, Rattanasopa C, Maiwald S, Krist DT, Scott DC, Steigenberger B, Prabu JR, Schulman BA, Kleiger G. Mechanism of millisecond Lys48-linked poly-ubiquitin chain formation by cullin-RING ligases. Nat Struct Mol Biol 2024; 31:378-389. [PMID: 38326650 PMCID: PMC10873206 DOI: 10.1038/s41594-023-01206-1] [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] [Received: 08/07/2023] [Accepted: 12/21/2023] [Indexed: 02/09/2024]
Abstract
E3 ubiquitin ligases, in collaboration with E2 ubiquitin-conjugating enzymes, modify proteins with poly-ubiquitin chains. Cullin-RING ligase (CRL) E3s use Cdc34/UBE2R-family E2s to build Lys48-linked poly-ubiquitin chains to control an enormous swath of eukaryotic biology. Yet the molecular mechanisms underlying this exceptional linkage specificity and millisecond kinetics of poly-ubiquitylation remain unclear. Here we obtain cryogenic-electron microscopy (cryo-EM) structures that provide pertinent insight into how such poly-ubiquitin chains are forged. The CRL RING domain not only activates the E2-bound ubiquitin but also shapes the conformation of a distinctive UBE2R2 loop, positioning both the ubiquitin to be transferred and the substrate-linked acceptor ubiquitin within the active site. The structures also reveal how the ubiquitin-like protein NEDD8 uniquely activates CRLs during chain formation. NEDD8 releases the RING domain from the CRL, but unlike previous CRL-E2 structures, does not contact UBE2R2. These findings suggest how poly-ubiquitylation may be accomplished by many E2s and E3s.
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Affiliation(s)
- Joanna Liwocha
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Jerry Li
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV, USA
| | - Nicholas Purser
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV, USA
| | - Chutima Rattanasopa
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV, USA
| | - Samuel Maiwald
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - David T Krist
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Daniel C Scott
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Barbara Steigenberger
- Mass Spectrometry Core Facility, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - J Rajan Prabu
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Brenda A Schulman
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany.
| | - Gary Kleiger
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany.
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV, USA.
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3
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Chrustowicz J, Sherpa D, Li J, Langlois CR, Papadopoulou EC, Vu DT, Hehl LA, Karayel Ö, Beier V, von Gronau S, Müller J, Prabu JR, Mann M, Kleiger G, Alpi AF, Schulman BA. Multisite phosphorylation dictates selective E2-E3 pairing as revealed by Ubc8/UBE2H-GID/CTLH assemblies. Mol Cell 2024; 84:293-308.e14. [PMID: 38113892 PMCID: PMC10843684 DOI: 10.1016/j.molcel.2023.11.027] [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] [Received: 07/11/2023] [Revised: 10/29/2023] [Accepted: 11/21/2023] [Indexed: 12/21/2023]
Abstract
Ubiquitylation is catalyzed by coordinated actions of E3 and E2 enzymes. Molecular principles governing many important E3-E2 partnerships remain unknown, including those for RING-family GID/CTLH E3 ubiquitin ligases and their dedicated E2, Ubc8/UBE2H (yeast/human nomenclature). GID/CTLH-Ubc8/UBE2H-mediated ubiquitylation regulates biological processes ranging from yeast metabolic signaling to human development. Here, cryoelectron microscopy (cryo-EM), biochemistry, and cell biology reveal this exquisitely specific E3-E2 pairing through an unconventional catalytic assembly and auxiliary interactions 70-100 Å away, mediated by E2 multisite phosphorylation. Rather than dynamic polyelectrostatic interactions reported for other ubiquitylation complexes, multiple Ubc8/UBE2H phosphorylation sites within acidic CK2-targeted sequences specifically anchor the E2 C termini to E3 basic patches. Positions of phospho-dependent interactions relative to the catalytic domains correlate across evolution. Overall, our data show that phosphorylation-dependent multivalency establishes a specific E3-E2 partnership, is antagonistic with dephosphorylation, rigidifies the catalytic centers within a flexing GID E3-substrate assembly, and facilitates substrate collision with ubiquitylation active sites.
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Affiliation(s)
- Jakub Chrustowicz
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Dawafuti Sherpa
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Jerry Li
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, NV 89154, USA
| | - Christine R Langlois
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Eleftheria C Papadopoulou
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried 82152, Germany; Technical University of Munich, School of Natural Sciences, Munich 85748, Germany
| | - D Tung Vu
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Laura A Hehl
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried 82152, Germany; Technical University of Munich, School of Natural Sciences, Munich 85748, Germany
| | - Özge Karayel
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Viola Beier
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Susanne von Gronau
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Judith Müller
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - J Rajan Prabu
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Matthias Mann
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Gary Kleiger
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, NV 89154, USA
| | - Arno F Alpi
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Brenda A Schulman
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried 82152, Germany; Technical University of Munich, School of Natural Sciences, Munich 85748, Germany.
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4
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Purser N, Tripathi-Giesgen I, Li J, Scott DC, Horn-Ghetko D, Baek K, Schulman BA, Alpi AF, Kleiger G. Catalysis of non-canonical protein ubiquitylation by the ARIH1 ubiquitin ligase. Biochem J 2023; 480:1817-1831. [PMID: 37870100 PMCID: PMC10657180 DOI: 10.1042/bcj20230373] [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] [Received: 08/31/2023] [Revised: 10/19/2023] [Accepted: 10/23/2023] [Indexed: 10/24/2023]
Abstract
Protein ubiquitylation typically involves isopeptide bond formation between the C-terminus of ubiquitin to the side-chain amino group on Lys residues. However, several ubiquitin ligases (E3s) have recently been identified that ubiquitylate proteins on non-Lys residues. For instance, HOIL-1 belongs to the RING-in-between RING (RBR) class of E3s and has an established role in Ser ubiquitylation. Given the homology between HOIL-1 and ARIH1, an RBR E3 that functions with the large superfamily of cullin-RING E3 ligases (CRLs), a biochemical investigation was undertaken, showing ARIH1 catalyzes Ser ubiquitylation to CRL-bound substrates. However, the efficiency of ubiquitylation was exquisitely dependent on the location and chemical environment of the Ser residue within the primary structure of the substrate. Comprehensive mutagenesis of the ARIH1 Rcat domain identified residues whose mutation severely impacted both oxyester and isopeptide bond formation at the preferred site for Ser ubiquitylation while only modestly affecting Lys ubiquitylation at the physiological site. The results reveal dual isopeptide and oxyester protein ubiquitylation activities of ARIH1 and set the stage for physiological investigations into this function of emerging importance.
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Affiliation(s)
- Nicholas Purser
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV, U.S.A
| | - Ishita Tripathi-Giesgen
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Jerry Li
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV, U.S.A
| | - Daniel C. Scott
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, U.S.A
| | - Daniel Horn-Ghetko
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Kheewoong Baek
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Brenda A. Schulman
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, U.S.A
| | - Arno F. Alpi
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Gary Kleiger
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV, U.S.A
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5
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Scott DC, King MT, Baek K, Gee CT, Kalathur R, Li J, Purser N, Nourse A, Chai SC, Vaithiyalingam S, Chen T, Lee RE, Elledge SJ, Kleiger G, Schulman BA. E3 ligase autoinhibition by C-degron mimicry maintains C-degron substrate fidelity. Mol Cell 2023; 83:770-786.e9. [PMID: 36805027 PMCID: PMC10080726 DOI: 10.1016/j.molcel.2023.01.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [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] [Received: 08/31/2022] [Revised: 12/19/2022] [Accepted: 01/18/2023] [Indexed: 02/18/2023]
Abstract
E3 ligase recruitment of proteins containing terminal destabilizing motifs (degrons) is emerging as a major form of regulation. How those E3s discriminate bona fide substrates from other proteins with terminal degron-like sequences remains unclear. Here, we report that human KLHDC2, a CRL2 substrate receptor targeting C-terminal Gly-Gly degrons, is regulated through interconversion between two assemblies. In the self-inactivated homotetramer, KLHDC2's C-terminal Gly-Ser motif mimics a degron and engages the substrate-binding domain of another protomer. True substrates capture the monomeric CRL2KLHDC2, driving E3 activation by neddylation and subsequent substrate ubiquitylation. Non-substrates such as NEDD8 bind KLHDC2 with high affinity, but its slow on rate prevents productive association with CRL2KLHDC2. Without substrate, neddylated CRL2KLHDC2 assemblies are deactivated via distinct mechanisms: the monomer by deneddylation and the tetramer by auto-ubiquitylation. Thus, substrate specificity is amplified by KLHDC2 self-assembly acting like a molecular timer, where only bona fide substrates may bind before E3 ligase inactivation.
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Affiliation(s)
- Daniel C Scott
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
| | - Moeko T King
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Kheewoong Baek
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Clifford T Gee
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Ravi Kalathur
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Protein Technologies Center, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Jerry Li
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV, USA
| | - Nicholas Purser
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV, USA
| | - Amanda Nourse
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Protein Technologies Center, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Sergio C Chai
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Sivaraja Vaithiyalingam
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Protein Technologies Center, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Taosheng Chen
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Richard E Lee
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Stephen J Elledge
- Division of Genetics, Brigham and Women's Hospital, Howard Hughes Medical Institute, Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Gary Kleiger
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV, USA
| | - Brenda A Schulman
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
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6
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Horn-Ghetko D, Krist DT, Prabu JR, Baek K, Mulder MPC, Klügel M, Scott DC, Ovaa H, Kleiger G, Schulman BA. Ubiquitin ligation to F-box protein targets by SCF-RBR E3-E3 super-assembly. Nature 2021; 590:671-676. [PMID: 33536622 PMCID: PMC7904520 DOI: 10.1038/s41586-021-03197-9] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [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: 05/21/2020] [Accepted: 12/18/2020] [Indexed: 01/30/2023]
Abstract
E3 ligases are typically classified by hallmark domains such as RING and RBR, which are thought to specify unique catalytic mechanisms of ubiquitin transfer to recruited substrates1,2. However, rather than functioning individually, many neddylated cullin-RING E3 ligases (CRLs) and RBR-type E3 ligases in the ARIH family-which together account for nearly half of all ubiquitin ligases in humans-form E3-E3 super-assemblies3-7. Here, by studying CRLs in the SKP1-CUL1-F-box (SCF) family, we show how neddylated SCF ligases and ARIH1 (an RBR-type E3 ligase) co-evolved to ubiquitylate diverse substrates presented on various F-box proteins. We developed activity-based chemical probes that enabled cryo-electron microscopy visualization of steps in E3-E3 ubiquitylation, initiating with ubiquitin linked to the E2 enzyme UBE2L3, then transferred to the catalytic cysteine of ARIH1, and culminating in ubiquitin linkage to a substrate bound to the SCF E3 ligase. The E3-E3 mechanism places the ubiquitin-linked active site of ARIH1 adjacent to substrates bound to F-box proteins (for example, substrates with folded structures or limited length) that are incompatible with previously described conventional RING E3-only mechanisms. The versatile E3-E3 super-assembly may therefore underlie widespread ubiquitylation.
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Affiliation(s)
- Daniel Horn-Ghetko
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - David T Krist
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
- Carle Illinois College of Medicine, Champaign, IL, USA
| | - J Rajan Prabu
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Kheewoong Baek
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Monique P C Mulder
- Oncode Institute, Department of Cell and Chemical Biology, Chemical Immunology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Maren Klügel
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Daniel C Scott
- Department of Structural Biology, St Jude Children's Research Hospital, Memphis, TN, USA
| | - Huib Ovaa
- Oncode Institute, Department of Cell and Chemical Biology, Chemical Immunology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Gary Kleiger
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV, USA
| | - Brenda A Schulman
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany.
- Department of Structural Biology, St Jude Children's Research Hospital, Memphis, TN, USA.
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7
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Liwocha J, Krist DT, van der Heden van Noort GJ, Hansen FM, Truong VH, Karayel O, Purser N, Houston D, Burton N, Bostock MJ, Sattler M, Mann M, Harrison JS, Kleiger G, Ovaa H, Schulman BA. Linkage-specific ubiquitin chain formation depends on a lysine hydrocarbon ruler. Nat Chem Biol 2020; 17:272-279. [PMID: 33288957 PMCID: PMC7904580 DOI: 10.1038/s41589-020-00696-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 09/10/2020] [Accepted: 10/14/2020] [Indexed: 02/08/2023]
Abstract
Virtually all aspects of cell biology are regulated by a ubiquitin code
where distinct ubiquitin chain architectures guide the binding events and
itineraries of modified substrates. Various combinations of E2 and E3 enzymes
accomplish chain formation by forging isopeptide bonds between the C-terminus of
their transiently-linked donor ubiquitin and a specific nucleophilic amino acid
on the acceptor ubiquitin, yet it is unknown whether the fundamental feature of
most acceptors - the lysine side-chain - affects catalysis. Here, use of
synthetic ubiquitins with non-natural acceptor site replacements reveals that
the aliphatic side-chain specifying reactive amine geometry is a determinant of
the ubiquitin code, through unanticipated and complex reliance of many distinct
ubiquitin carrying enzymes on a canonical acceptor lysine.
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Affiliation(s)
- Joanna Liwocha
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - David T Krist
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany.,Carle Illinois College of Medicine, Champaign, IL, USA
| | - Gerbrand J van der Heden van Noort
- Oncode Institute and Department of Cell and Chemical Biology, Chemical Immunology, Leiden University Medical Centre, Leiden, the Netherlands
| | - Fynn M Hansen
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Vinh H Truong
- Department of Chemistry, University of the Pacific, Stockton, CA, USA
| | - Ozge Karayel
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Nicholas Purser
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV, USA
| | - Daniel Houston
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV, USA
| | - Nicole Burton
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV, USA
| | - Mark J Bostock
- Biomolecular NMR and Center for Integrated Protein Science Munich at Department Chemie, Technical University of Munich, Garching, Germany.,Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany
| | - Michael Sattler
- Biomolecular NMR and Center for Integrated Protein Science Munich at Department Chemie, Technical University of Munich, Garching, Germany.,Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany
| | - Matthias Mann
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Joseph S Harrison
- Department of Chemistry, University of the Pacific, Stockton, CA, USA
| | - Gary Kleiger
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV, USA.
| | - Huib Ovaa
- Oncode Institute and Department of Cell and Chemical Biology, Chemical Immunology, Leiden University Medical Centre, Leiden, the Netherlands.
| | - Brenda A Schulman
- Department of Molecular Machines and Signaling, Max Planck Institute of Biochemistry, Martinsried, Germany.
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8
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Hill S, Reichermeier K, Scott DC, Samentar L, Coulombe-Huntington J, Izzi L, Tang X, Ibarra R, Bertomeu T, Moradian A, Sweredoski MJ, Caberoy N, Schulman BA, Sicheri F, Tyers M, Kleiger G. Robust cullin-RING ligase function is established by a multiplicity of poly-ubiquitylation pathways. eLife 2019; 8:e51163. [PMID: 31868589 PMCID: PMC6975927 DOI: 10.7554/elife.51163] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [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: 08/17/2019] [Accepted: 12/22/2019] [Indexed: 12/24/2022] Open
Abstract
The cullin-RING ligases (CRLs) form the major family of E3 ubiquitin ligases. The prototypic CRLs in yeast, called SCF enzymes, employ a single E2 enzyme, Cdc34, to build poly-ubiquitin chains required for degradation. In contrast, six different human E2 and E3 enzyme activities, including Cdc34 orthologs UBE2R1 and UBE2R2, appear to mediate SCF-catalyzed substrate polyubiquitylation in vitro. The combinatorial interplay of these enzymes raises questions about genetic buffering of SCFs in human cells and challenges the dogma that E3s alone determine substrate specificity. To enable the quantitative comparisons of SCF-dependent ubiquitylation reactions with physiological enzyme concentrations, mass spectrometry was employed to estimate E2 and E3 levels in cells. In combination with UBE2R1/2, the E2 UBE2D3 and the E3 ARIH1 both promoted SCF-mediated polyubiquitylation in a substrate-specific fashion. Unexpectedly, UBE2R2 alone had negligible ubiquitylation activity at physiological concentrations and the ablation of UBE2R1/2 had no effect on the stability of SCF substrates in cells. A genome-wide CRISPR screen revealed that an additional E2 enzyme, UBE2G1, buffers against the loss of UBE2R1/2. UBE2G1 had robust in vitro chain extension activity with SCF, and UBE2G1 knockdown in cells lacking UBE2R1/2 resulted in stabilization of the SCF substrates p27 and CYCLIN E as well as the CUL2-RING ligase substrate HIF1α. The results demonstrate the human SCF enzyme system is diversified by association with multiple catalytic enzyme partners.
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Affiliation(s)
- Spencer Hill
- Department of Chemistry and BiochemistryUniversity of NevadaLas VegasUnited States
| | - Kurt Reichermeier
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaUnited States
- Department of Discovery ProteomicsGenentech IncSouth San FranciscoUnited States
- Department of Discovery OncologyGenentech IncSouth San FranciscoUnited States
| | - Daniel C Scott
- Department of Structural BiologySt Jude Children's Research HospitalMemphisUnited States
| | - Lorena Samentar
- School of Life SciencesUniversity of NevadaLas VegasUnited States
- University of the PhilippinesIloiloPhilippines
| | - Jasmin Coulombe-Huntington
- Institute for Research in Immunology and Cancer, Department of MedicineUniversity of MontrealMontrealCanada
| | - Luisa Izzi
- Institute for Research in Immunology and Cancer, Department of MedicineUniversity of MontrealMontrealCanada
| | - Xiaojing Tang
- Lunenfeld-Tanenbaum Research InstituteMount Sinai HospitalTorontoCanada
| | - Rebeca Ibarra
- Department of Chemistry and BiochemistryUniversity of NevadaLas VegasUnited States
| | - Thierry Bertomeu
- Institute for Research in Immunology and Cancer, Department of MedicineUniversity of MontrealMontrealCanada
| | - Annie Moradian
- Proteome Exploration Laboratory, Division of Biology and Biological Engineering, Beckman InstituteCalifornia Institute of TechnologyPasadenaUnited States
| | - Michael J Sweredoski
- Proteome Exploration Laboratory, Division of Biology and Biological Engineering, Beckman InstituteCalifornia Institute of TechnologyPasadenaUnited States
| | - Nora Caberoy
- School of Life SciencesUniversity of NevadaLas VegasUnited States
| | - Brenda A Schulman
- Max Planck Institute of Biochemistry, Molecular Machines and SignalingMartinsriedGermany
| | - Frank Sicheri
- Lunenfeld-Tanenbaum Research InstituteMount Sinai HospitalTorontoCanada
| | - Mike Tyers
- Institute for Research in Immunology and Cancer, Department of MedicineUniversity of MontrealMontrealCanada
| | - Gary Kleiger
- Department of Chemistry and BiochemistryUniversity of NevadaLas VegasUnited States
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9
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Jones RD, Enam C, Ibarra R, Borror HR, Mostoller KE, Fredrickson EK, Lin J, Chuang E, March Z, Shorter J, Ravid T, Kleiger G, Gardner RG. The extent of Ssa1/Ssa2 Hsp70 chaperone involvement in nuclear protein quality control degradation varies with the substrate. Mol Biol Cell 2019; 31:221-233. [PMID: 31825716 PMCID: PMC7001477 DOI: 10.1091/mbc.e18-02-0121] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Protein misfolding is a recurring phenomenon that cells must manage; otherwise misfolded proteins can aggregate and become toxic should they persist. To counter this burden, cells have evolved protein quality control (PQC) mechanisms that manage misfolded proteins. Two classes of systems that function in PQC are chaperones that aid in protein folding and ubiquitin-protein ligases that ubiquitinate misfolded proteins for proteasomal degradation. How folding and degradative PQC systems interact and coordinate their respective functions is not yet fully understood. Previous studies of PQC degradation pathways in the endoplasmic reticulum and cytosol have led to the prevailing idea that these pathways require the activity of Hsp70 chaperones. Here, we find that involvement of the budding yeast Hsp70 chaperones Ssa1 and Ssa2 in nuclear PQC degradation varies with the substrate. In particular, nuclear PQC degradation mediated by the yeast ubiquitin-protein ligase San1 often involves Ssa1/Ssa2, but San1 substrate recognition and ubiquitination can proceed without these Hsp70 chaperone functions in vivo and in vitro. Our studies provide new insights into the variability of Hsp70 chaperone involvement with a nuclear PQC degradation pathway.
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Affiliation(s)
- Ramon D Jones
- Department of Pharmacology, University of Washington, Seattle, WA 98195
| | - Charisma Enam
- Department of Pharmacology, University of Washington, Seattle, WA 98195
| | - Rebeca Ibarra
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, NV 89154
| | - Heather R Borror
- Department of Pharmacology, University of Washington, Seattle, WA 98195
| | | | | | - JiaBei Lin
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Edward Chuang
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Zachary March
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Tommer Ravid
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Givat-Ram, -Jerusalem 91904, Israel
| | - Gary Kleiger
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, NV 89154
| | - Richard G Gardner
- Department of Pharmacology, University of Washington, Seattle, WA 98195
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10
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Affiliation(s)
- Spencer Hill
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV, USA
| | - Gary Kleiger
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV, USA
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11
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Abstract
Cullin-RING (CRL) and RING1-IBR-RING2 (RBR) are two distinct types of ubiquitin ligases. In this issue, Scott et al. show that CRLs activate the RBR enzyme ARIH1 to initiate ubiquitin chains on CRL substrates, thereby marking an unexpected and important advance in our understanding of both enzymes.
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Affiliation(s)
- Gary Kleiger
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, 4505 South Maryland Parkway, Las Vegas, NV 89154, USA
| | - Raymond Deshaies
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 East California Blvd, Pasadena, CA 91125, USA; Howard Hughes Medical Institute.
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12
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Ibarra R, Sandoval D, Fredrickson EK, Gardner RG, Kleiger G. The San1 Ubiquitin Ligase Functions Preferentially with Ubiquitin-conjugating Enzyme Ubc1 during Protein Quality Control. J Biol Chem 2016; 291:18778-90. [PMID: 27405755 DOI: 10.1074/jbc.m116.737619] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Indexed: 11/06/2022] Open
Abstract
Protein quality control (PQC) is a critical process wherein misfolded or damaged proteins are cleared from the cell to maintain protein homeostasis. In eukaryotic cells, the removal of misfolded proteins is primarily accomplished by the ubiquitin-proteasome system. In the ubiquitin-proteasome system, ubiquitin-conjugating enzymes and ubiquitin ligases append polyubiquitin chains onto misfolded protein substrates signaling for their degradation. The kinetics of protein ubiquitylation are paramount as a balance must be achieved between the rapid removal of misfolded proteins versus providing sufficient time for protein chaperones to attempt refolding. To uncover the molecular basis for how PQC substrate ubiquitylation rates are controlled, the reaction catalyzed by nuclear ubiquitin ligase San1 was reconstituted in vitro Our results demonstrate that San1 can function with two ubiquitin-conjugating enzymes, Cdc34 and Ubc1. Although Cdc34 and Ubc1 are both sufficient for promoting San1 activity, San1 functions preferentially with Ubc1, including when both Ubc1 and Cdc34 are present. Notably, a homogeneous peptide that mimics a misfolded PQC substrate was developed and enabled quantification of the kinetics of San1-catalyzed ubiquitylation reactions. We discuss how these results may have broad implications for the regulation of PQC-mediated protein degradation.
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Affiliation(s)
- Rebeca Ibarra
- From the Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154 and
| | - Daniella Sandoval
- From the Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154 and
| | - Eric K Fredrickson
- the Department of Pharmacology, University of Washington, Seattle, Washington 98195
| | - Richard G Gardner
- the Department of Pharmacology, University of Washington, Seattle, Washington 98195
| | - Gary Kleiger
- From the Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154 and
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13
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Sandoval D, Hill S, Ziemba A, Lewis S, Kuhlman B, Kleiger G. Ubiquitin-conjugating enzyme Cdc34 and ubiquitin ligase Skp1-cullin-F-box ligase (SCF) interact through multiple conformations. J Biol Chem 2014; 290:1106-18. [PMID: 25425648 DOI: 10.1074/jbc.m114.615559] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
In the ubiquitin-proteasome system, protein substrates are degraded via covalent modification by a polyubiquitin chain. The polyubiquitin chain must be assembled rapidly in cells, because a chain of at least four ubiquitins is required to signal for degradation, and chain-editing enzymes in the cell may cleave premature polyubiquitin chains before achieving this critical length. The ubiquitin-conjugating enzyme Cdc34 and ubiquitin ligase SCF are capable of building polyubiquitin chains onto protein substrates both rapidly and processively; this may be explained at least in part by the atypically fast rate of Cdc34 and SCF association. This rapid association has been attributed to electrostatic interactions between the acidic C-terminal tail of Cdc34 and a feature on SCF called the basic canyon. However, the structural aspects of the Cdc34-SCF interaction and how they permit rapid complex formation remain elusive. Here, we use protein cross-linking to demonstrate that the Cdc34-SCF interaction occurs in multiple conformations, where several residues from the Cdc34 acidic tail are capable of contacting a broad region of the SCF basic canyon. Similar patterns of cross-linking are also observed between Cdc34 and the Cul1 paralog Cul2, implicating the same mechanism for the Cdc34-SCF interaction in other members of the cullin-RING ubiquitin ligases. We discuss how these results can explain the rapid association of Cdc34 and SCF.
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Affiliation(s)
- Daniella Sandoval
- From the Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154-4003 and
| | - Spencer Hill
- From the Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154-4003 and
| | - Amy Ziemba
- From the Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154-4003 and
| | - Steven Lewis
- the Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina 27599-7260
| | - Brian Kuhlman
- the Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina 27599-7260
| | - Gary Kleiger
- From the Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154-4003 and
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14
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Huang H, Ceccarelli DF, Orlicky S, St-Cyr DJ, Ziemba A, Garg P, Plamondon S, Auer M, Sidhu S, Marinier A, Kleiger G, Tyers M, Sicheri F. E2 enzyme inhibition by stabilization of a low-affinity interface with ubiquitin. Nat Chem Biol 2014; 10:156-163. [PMID: 24316736 PMCID: PMC3905752 DOI: 10.1038/nchembio.1412] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [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: 04/15/2013] [Accepted: 10/31/2013] [Indexed: 11/09/2022]
Abstract
Weak protein interactions between ubiquitin and the ubiquitin-proteasome system (UPS) enzymes that mediate its covalent attachment to substrates serve to position ubiquitin for optimal catalytic transfer. We show that a small-molecule inhibitor of the E2 ubiquitin-conjugating enzyme Cdc34A, called CC0651, acts by trapping a weak interaction between ubiquitin and the E2 donor ubiquitin-binding site. A structure of the ternary CC0651-Cdc34A-ubiquitin complex reveals that the inhibitor engages a composite binding pocket formed from Cdc34A and ubiquitin. CC0651 also suppresses the spontaneous hydrolysis rate of the Cdc34A-ubiquitin thioester without decreasing the interaction between Cdc34A and the RING domain subunit of the E3 enzyme. Stabilization of the numerous other weak interactions between ubiquitin and UPS enzymes by small molecules may be a feasible strategy to selectively inhibit different UPS activities.
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Affiliation(s)
- Hao Huang
- Centre for Systems Biology, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Canada M5G 1X5
| | - Derek F Ceccarelli
- Centre for Systems Biology, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Canada M5G 1X5
| | - Stephen Orlicky
- Centre for Systems Biology, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Canada M5G 1X5
| | - Daniel J. St-Cyr
- Institute for Research in Immunology and Cancer, University of Montreal, Montreal, Québec H3C 3J7, Canada
| | - Amy Ziemba
- Department of Chemistry, University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Las Vegas, NV, 89154
| | - Pankaj Garg
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
- Banting and Best Department of Medical Research, Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | - Serge Plamondon
- Institute for Research in Immunology and Cancer, University of Montreal, Montreal, Québec H3C 3J7, Canada
| | - Manfred Auer
- School of Biological Sciences, University of Edinburgh, Mayfield Road, Edinburgh EH9 3JR United Kingdom
| | - Sachdev Sidhu
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
- Banting and Best Department of Medical Research, Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | - Anne Marinier
- Institute for Research in Immunology and Cancer, University of Montreal, Montreal, Québec H3C 3J7, Canada
- Department of Chemistry, University of Montreal, Montreal, Québec H3C 3J7, Canada
| | - Gary Kleiger
- Department of Chemistry, University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Las Vegas, NV, 89154
| | - Mike Tyers
- Institute for Research in Immunology and Cancer, University of Montreal, Montreal, Québec H3C 3J7, Canada
- Department of Medicine, University of Montreal, Montreal, Québec H3C 3J7, Canada
| | - Frank Sicheri
- Centre for Systems Biology, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Canada M5G 1X5
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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15
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Kleiger G, Mayor T. Perilous journey: a tour of the ubiquitin-proteasome system. Trends Cell Biol 2014; 24:352-9. [PMID: 24457024 DOI: 10.1016/j.tcb.2013.12.003] [Citation(s) in RCA: 230] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Revised: 12/03/2013] [Accepted: 12/19/2013] [Indexed: 10/25/2022]
Abstract
Eukaryotic cells are equipped to degrade proteins via the ubiquitin-proteasome system (UPS). Proteins become degraded upon their conjugation to chains of ubiquitin where they are then directed to the 26S proteasome, a macromolecular protease. The transfer of ubiquitin to proteins and their subsequent degradation are highly complex processes, and new research is beginning to uncover the molecular details of how ubiquitination and degradation take place in the cell. We review some of the new data providing insights into how these processes occur. Although distinct mechanisms are often observed, some common themes are emerging for how the UPS guides protein substrates through their final journey.
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Affiliation(s)
- Gary Kleiger
- Department of Chemistry, University of Nevada, Las Vegas, 4505 South Maryland Parkway, Las Vegas, NV 89154-4003, USA.
| | - Thibault Mayor
- Department of Biochemistry and Molecular Biology, Centre of High-Throughput Biology, University of British Columbia, 2125 East Mall, Vancouver, BC V6T1Z4, Canada.
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16
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Ziemba A, Hill S, Sandoval D, Webb K, Bennett EJ, Kleiger G. Multimodal mechanism of action for the Cdc34 acidic loop: a case study for why ubiquitin-conjugating enzymes have loops and tails. J Biol Chem 2013; 288:34882-96. [PMID: 24129577 DOI: 10.1074/jbc.m113.509190] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Together with ubiquitin ligases (E3), ubiquitin-conjugating enzymes (E2) are charged with the essential task of synthesizing ubiquitin chains onto protein substrates. Some 75% of the known E2s in the human proteome contain unique insertions in their primary sequences, yet it is largely unclear what effect these insertions impart on the ubiquitination reaction. Cdc34 is an important E2 with prominent roles in cell cycle regulation and signal transduction. The amino acid sequence of Cdc34 contains an insertion distal to the active site that is absent in most other E2s, yet this acidic loop (named for its four invariably conserved acidic residues) is critical for Cdc34 function both in vitro and in vivo. Here we have investigated how the acidic loop in human Cdc34 promotes ubiquitination, identifying two key molecular events during which the acidic loop exerts its influence. First, the acidic loop promotes the interaction between Cdc34 and its ubiquitin ligase partner, SCF. Second, two glutamic acid residues located on the distal side of the loop collaborate with an invariably conserved histidine on the proximal side of the loop to suppress the pKa of an ionizing species on ubiquitin or Cdc34 which greatly contributes to Cdc34 catalysis. These results demonstrate that insertions can guide E2s to their physiologically relevant ubiquitin ligases as well as provide essential modalities that promote catalysis.
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Affiliation(s)
- Amy Ziemba
- From the Department of Chemistry, University of Nevada, Las Vegas, Nevada 89154 and
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17
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Saha A, Lewis S, Kleiger G, Kuhlman B, Deshaies RJ. Essential role for ubiquitin-ubiquitin-conjugating enzyme interaction in ubiquitin discharge from Cdc34 to substrate. Mol Cell 2011; 42:75-83. [PMID: 21474069 DOI: 10.1016/j.molcel.2011.03.016] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 02/22/2011] [Accepted: 03/24/2011] [Indexed: 12/16/2022]
Abstract
During ubiquitin conjugation, the thioester bond that links "donor" ubiquitin to ubiquitin-conjugating enzyme (E2) undergoes nucleophilic attack by the ɛ-amino group of an acceptor lysine, resulting in formation of an isopeptide bond. Models of ubiquitination have envisioned the donor ubiquitin to be a passive participant in this process. However, we show here that the I44A mutation in ubiquitin profoundly inhibits its ability to serve as a donor for ubiquitin chain initiation or elongation, but can be rescued by computationally predicted compensatory mutations in the E2 Cdc34. The donor defect of ubiquitin-I44A can be partially suppressed either by using a low pKa amine (hydroxylamine) as the acceptor or by performing reactions at higher pH, suggesting that the discharge defect arises in part due to inefficient deprotonation of the acceptor lysine. We propose that interaction between Cdc34 and the donor ubiquitin organizes the active site to promote efficient ubiquitination of substrate.
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Affiliation(s)
- Anjanabha Saha
- Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA
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18
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Kleiger G, Hao B, Mohl DA, Deshaies RJ. The acidic tail of the Cdc34 ubiquitin-conjugating enzyme functions in both binding to and catalysis with ubiquitin ligase SCFCdc4. J Biol Chem 2009; 284:36012-36023. [PMID: 19875449 PMCID: PMC2794717 DOI: 10.1074/jbc.m109.058529] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [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: 08/21/2009] [Revised: 10/22/2009] [Indexed: 12/15/2022] Open
Abstract
Ubiquitin ligases, together with their cognate ubiquitin-conjugating enzymes, are responsible for the ubiquitylation of proteins, a process that regulates a myriad of eukaryotic cellular functions. The first cullin-RING ligase discovered, yeast SCF(Cdc4), functions with the conjugating enzyme Cdc34 to regulate the cell cycle. Cdc34 orthologs are notable for their highly acidic C-terminal extension. Here we confirm that the Cdc34 acidic C-terminal tail has a role in Cdc34 binding to SCF(Cdc4) and makes a major contribution to the submicromolar K(m) of Cdc34 for SCF(Cdc4). Moreover, we demonstrate that a key functional property of the tail is its acidity. Our analysis also uncovers an unexpected new function for the acidic tail in promoting catalysis. We demonstrate that SCF is functional when Cdc34 is fused to the C terminus of Cul1 and that this fusion retains partial function even when the acidic tail has been deleted. The Cdc34-SCF fusion proteins that lack the acidic tail must interact in a fundamentally different manner than unfused SCF and wild type Cdc34, demonstrating that distinct mechanisms of E2 recruitment to E3, as is seen in nature, can sustain substrate ubiquitylation. Finally, a search of the yeast proteome uncovered scores of proteins containing highly acidic stretches of amino acids, hinting that electrostatic interactions may be a common mechanism for facilitating protein assembly.
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Affiliation(s)
- Gary Kleiger
- Howard Hughes Medical Institute and the Division of Biology, California Institute of Technology, Pasadena, California 91125
| | - Bing Hao
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, Farmington, Connecticut 06030
| | - Dane A Mohl
- Howard Hughes Medical Institute and the Division of Biology, California Institute of Technology, Pasadena, California 91125
| | - Raymond J Deshaies
- Howard Hughes Medical Institute and the Division of Biology, California Institute of Technology, Pasadena, California 91125.
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19
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Kleiger G, Saha A, Lewis S, Kuhlman B, Deshaies RJ. Rapid E2-E3 assembly and disassembly enable processive ubiquitylation of cullin-RING ubiquitin ligase substrates. Cell 2009; 139:957-68. [PMID: 19945379 DOI: 10.1016/j.cell.2009.10.030] [Citation(s) in RCA: 156] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Revised: 08/12/2009] [Accepted: 09/18/2009] [Indexed: 01/14/2023]
Abstract
Degradation by the ubiquitin-proteasome system requires assembly of a polyubiquitin chain upon substrate. However, the structural and mechanistic features that enable template-independent processive chain synthesis are unknown. We show that chain assembly by ubiquitin ligase SCF and ubiquitin-conjugating enzyme Cdc34 is facilitated by the unusual nature of Cdc34-SCF transactions: Cdc34 binds SCF with nanomolar affinity, nevertheless the complex is extremely dynamic. These properties are enabled by rapid association driven by electrostatic interactions between the acidic tail of Cdc34 and a basic 'canyon' in the Cul1 subunit of SCF. Ab initio docking between Cdc34 and Cul1 predicts intimate contact between the tail and the basic canyon, an arrangement confirmed by crosslinking and kinetic analysis of mutants. Basic canyon residues are conserved in both Cul1 paralogs and orthologs, suggesting that the same mechanism underlies processivity for all cullin-RING ubiquitin ligases. We discuss different strategies by which processive ubiquitin chain synthesis may be achieved.
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Affiliation(s)
- Gary Kleiger
- Howard Hughes Medical Institute and the Division of Biology, 156-29, California Institute of Technology, Pasadena, CA 91125, USA
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20
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Kleiger G, Panina EM, Mallick P, Eisenberg D. PFIT and PFRIT: bioinformatic algorithms for detecting glycosidase function from structure and sequence. Protein Sci 2003; 13:221-9. [PMID: 14691237 PMCID: PMC2286537 DOI: 10.1110/ps.03274104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The identification of the enzymes involved in the metabolism of simple and complex carbohydrates presents one bioinformatic challenge in the post-genomic era. Here, we present the PFIT and PFRIT algorithms for identifying those proteins adopting the alpha/beta barrel fold that function as glycosidases. These algorithms are based on the observation that proteins adopting the alpha/beta barrel fold share positions in their tertiary structures having equivalent sets of atomic interactions. These are conserved tertiary interaction positions, which have been implicated in both structure and function. Glycosidases adopting the alpha/beta barrel fold share more conserved tertiary interactions than alpha/beta barrel proteins having other functions. The enrichment pattern of conserved tertiary interactions in the glycosidases is the information that PFIT and PFRIT use to predict whether any given alpha/beta barrel will function as a glycosidase or not. Using as a test set a database of 19 glycosidase and 45 nonglycosidase alpha/beta barrel proteins with low sequence similarity, PFIT and PFRIT can correctly predict glycosidase function for 84% of the proteins known to function as glycosidases. PFIT and PFRIT incorrectly predict glycosidase function for 25% of the nonglycosidases. The program PSI-BLAST can also correctly identify 84% of the 19 glycosidases, however, it incorrectly predicts glycosidase function for 50% of the nonglycosidases (twofold greater than PFIT and PFRIT). Overall, we demonstrate that the structure-based PFIT and PFRIT algorithms are both more selective and sensitive for predicting glycosidase function than the sequence-based PSI-BLAST algorithm.
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Affiliation(s)
- Gary Kleiger
- Howard Hughes Medical Institute, University of California, Los Angeles-Department Of Energy, Institute of Genomics and Proteomics, UCLA, Los Angeles, California 90095, USA
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21
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Abstract
The C2H2 zinc finger is the most prevalent protein motif in the mammalian proteome. Two C2H2 fingers in Ikaros are dedicated to homotypic interactions between family members. We show here that these fingers comprise a bona fide dimerization domain. Dimerization is highly selective, however, as homologous domains from the TRPS-1 and Drosophila Hunchback proteins support homodimerization, but not heterodimerization with Ikaros. Ikaros-Hunchback selectivity is determined by 11 residues concentrated within the alpha-helical regions typically involved in base recognition. Preferential homodimerization of one chimeric protein predicts a parallel dimer interface and establishes the feasibility of creating novel dimer specificities. These results demonstrate that the C2H2 motif provides a versatile platform for both sequence-specific protein-nucleic acid interactions and highly specific dimerization.
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Affiliation(s)
- Aaron S McCarty
- Howard Hughes Medical Institute, Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
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22
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Kleiger G, Eisenberg D. GXXXG and GXXXA motifs stabilize FAD and NAD(P)-binding Rossmann folds through C(alpha)-H... O hydrogen bonds and van der waals interactions. J Mol Biol 2002; 323:69-76. [PMID: 12368099 DOI: 10.1016/s0022-2836(02)00885-9] [Citation(s) in RCA: 146] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Here we present evidence that domains in soluble proteins containing either the GXXXG or GXXXA motif are stabilized by the interaction of a beta-strand with the following alpha-helix. As an example, we characterized a beta-strand-helix interaction from the FAD or NAD(P)-binding Rossmann fold. The Rossmann fold is one of the three most highly represented folds in the Protein Data Bank (PDB). A subset of the proteins that adopt the Rossmann fold also bind to nucleotide cofactors such as FAD and NAD(P) and function as oxidoreductases. These Rossmann folds can often be identified by the short amino acid sequence motif, GX(1-2)GXXG. Here, we present evidence that in addition to this sequence motif, Rossmann folds that bind FAD and NAD(P) also typically contain either GXXXG or GXXXA motifs, where the first glycyl residue of these motifs and the third glycyl residue of the GX(1-2)GXXG motif are the same residue. These two motifs appear to stabilize the Rossmann fold: the first glycyl residue of either the GXXXG or GXXXA motif contacts the carbonyl oxygen atom from the first glycyl residue of the GX(1-2)GXXG motif consistent with the formation of a C(alpha)-H cdots, three dots, centered O hydrogen bond. In addition, both the glycyl and alanyl residues of the GXXXG or GXXXA motifs form van der Waals interactions with either a valine or isoleucine residue located either seven or eight residues further back along the polypeptide chain from the first glycine of the GXXXG or GXXXA motifs. Therefore, we combine both the GX(1-2)GXXG and GXXXG/A motifs into an extended motif, V/IXGX(1-2)GXXGXXXG/A, that is more strongly indicative than previously described motifs of Rossmann folds that bind FAD or NAD(P). The V/IXGX(1-2)GXXGXXXG/A motif can be used to search genomic sequence data and to annotate the function of proteins containing the motif as oxidoreductases, including proteins of previously unknown function.
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Affiliation(s)
- Gary Kleiger
- Howard Hughes Medical Institute, UCLA-DOE Center for Genomics and Proteomics, Molecular Biology Institute, UCLA, Box 951570, Los Angeles, CA 90095-1570, USA
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23
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Kleiger G, Grothe R, Mallick P, Eisenberg D. GXXXG and AXXXA: common alpha-helical interaction motifs in proteins, particularly in extremophiles. Biochemistry 2002; 41:5990-7. [PMID: 11993993 DOI: 10.1021/bi0200763] [Citation(s) in RCA: 158] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The GXXXG motif is a frequently occurring sequence of residues that is known to favor helix-helix interactions in membrane proteins. Here we show that the GXXXG motif is also prevalent in soluble proteins whose structures have been determined. Some 152 proteins from a non-redundant PDB set contain at least one alpha-helix with the GXXXG motif, 41 +/- 9% more than expected if glycine residues were uniformly distributed in those alpha-helices. More than 50% of the GXXXG-containing alpha-helices participate in helix-helix interactions. In fact, 26 of those helix-helix interactions are structurally similar to the helix-helix interaction of the glycophorin A dimer, where two transmembrane helices associate to form a dimer stabilized by the GXXXG motif. As for the glycophorin A structure, we find backbone-to-backbone atomic contacts of the C alpha-H...O type in each of these 26 helix-helix interactions that display the stereochemical hallmarks of hydrogen bond formation. These glycophorin A-like helix-helix interactions are enriched in the general set of helix-helix interactions containing the GXXXG motif, suggesting that the inferred C alpha-H...O hydrogen bonds stabilize the helix-helix interactions. In addition to the GXXXG motif, some 808 proteins from the non-redundant PDB set contain at least one alpha-helix with the AXXXA motif (30 +/- 3% greater than expected). Both the GXXXG and AXXXA motifs occur frequently in predicted alpha-helices from 24 fully sequenced genomes. Occurrence of the AXXXA motif is enhanced to a greater extent in thermophiles than in mesophiles, suggesting that helical interaction based on the AXXXA motif may be a common mechanism of thermostability in protein structures. We conclude that the GXXXG sequence motif stabilizes helix-helix interactions in proteins, and that the AXXXA sequence motif also stabilizes the folded state of proteins.
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Affiliation(s)
- Gary Kleiger
- Howard Hughes Medical Institute, UCLA-DOE Laboratory of Structural Biology and Molecular Medicine, Molecular Biology Institute, University of California at Los Angeles, P.O. Box 951570, Los Angeles, California 90095-1570, USA
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Kleiger G, Perry J, Eisenberg D. 3D structure and significance of the GPhiXXG helix packing motif in tetramers of the E1beta subunit of pyruvate dehydrogenase from the archeon Pyrobaculum aerophilum. Biochemistry 2001; 40:14484-92. [PMID: 11724561 DOI: 10.1021/bi011016k] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
As part of a structural genomics project, we have determined the 2.0 A structure of the E1beta subunit of pyruvate dehydrogenase from Pyrobaculum aerophilum (PA), a thermophilic archaeon. The overall fold of E1beta from PA is closely similar to the previously determined E1beta structures from humans (HU) and P. putida (PP). However, unlike the HU and PP structures, the PA structure was determined in the absence of its partner subunit, E1alpha. Significant structural rearrangements occur in E1beta when its E1alpha partner is absent, including rearrangement of several secondary structure elements such as helix C. Helix C is buried by E1alpha in the HU and PP structures, but makes crystal contacts in the PA structure that lead to an apparent beta(4) tetramer. Static light scattering and sedimentation velocity data are consistent with the formation of PA E1beta tetramers in solution. The interaction of helix C with its symmetry-related counterpart stabilizes the tetrameric interface, where two glycine residues on the same face of one helix create a packing surface for the other helix. This GPhiXXG helix-helix interaction motif has previously been found in interacting transmembrane helices, and is found here at the E1alpha-E1beta interface for both the HU and PP alpha(2)beta(2) tetramers. As a case study in structural genomics, this work illustrates that comparative analysis of protein structures can identify the structural significance of a sequence motif.
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Affiliation(s)
- G Kleiger
- Howard Hughes Medical Institute, UCLA-DOE Laboratory of Structural Biology and Molecular Medicine, Molecular Biology Institute, University of California, Los Angeles 90095-1570, USA
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Cobb BS, Morales-Alcelay S, Kleiger G, Brown KE, Fisher AG, Smale ST. Targeting of Ikaros to pericentromeric heterochromatin by direct DNA binding. Genes Dev 2000; 14:2146-60. [PMID: 10970879 PMCID: PMC316893 DOI: 10.1101/gad.816400] [Citation(s) in RCA: 214] [Impact Index Per Article: 8.9] [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] [Received: 05/01/2000] [Accepted: 06/30/2000] [Indexed: 11/25/2022]
Abstract
Ikaros is a sequence-specific DNA-binding protein that is essential for lymphocyte development. Little is known about the molecular function of Ikaros, although recent results have led to the hypothesis that it recruits genes destined for heritable inactivation to foci containing pericentromeric heterochromatin. To gain further insight into the functions of Ikaros, we have examined the mechanism by which it is targeted to centromeric foci. Efficient targeting of Ikaros was observed upon ectopic expression in 3T3 fibroblasts, demonstrating that lymphocyte-specific proteins and a lymphoid nuclear architecture are not required. Pericentromeric targeting did not result from an interaction with the Mi-2 remodeling factor, as only a small percentage of Mi-2 localized to centromeric foci in 3T3 cells. Rather, targeting was dependent on the amino-terminal DNA-binding zinc finger domain and carboxy-terminal dimerization domain of Ikaros. The carboxy-terminal domain was required only for homodimerization, as targeting was restored when this domain was replaced with a leucine zipper. Surprisingly, a detailed substitution mutant analysis of the amino-terminal domain revealed a close correlation between DNA-binding and pericentromeric targeting. These results show that DNA binding is essential for the pericentromeric localization of Ikaros, perhaps consistent with the presence of Ikaros binding sites within centromeric DNA repeats. Models for the function of Ikaros that are consistent with this targeting mechanism are discussed.
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MESH Headings
- 3T3 Cells
- Adenosine Triphosphatases
- Amino Acid Sequence
- Animals
- Autoantigens/metabolism
- Base Sequence
- Binding Sites
- Blotting, Western
- Cell Line
- Centromere/metabolism
- DNA/metabolism
- DNA Helicases
- DNA, Complementary/metabolism
- DNA-Binding Proteins
- Heterochromatin/metabolism
- Humans
- Ikaros Transcription Factor
- Mi-2 Nucleosome Remodeling and Deacetylase Complex
- Mice
- Microscopy, Confocal
- Microscopy, Fluorescence
- Models, Biological
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Protein Binding
- Protein Isoforms
- Protein Structure, Secondary
- Protein Structure, Tertiary
- Sequence Homology, Amino Acid
- Sequence Homology, Nucleic Acid
- Transcription Factors/biosynthesis
- Transcription Factors/chemistry
- Transcription Factors/genetics
- Transduction, Genetic
- Transfection
- Zinc Fingers
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Affiliation(s)
- B S Cobb
- Howard Hughes Medical Institute, Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, California 90095-1662, USA
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Kleiger G, Beamer LJ, Grothe R, Mallick P, Eisenberg D. The 1.7 A crystal structure of BPI: a study of how two dissimilar amino acid sequences can adopt the same fold. J Mol Biol 2000; 299:1019-34. [PMID: 10843855 DOI: 10.1006/jmbi.2000.3805] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have extended the resolution of the crystal structure of human bactericidal/permeability-increasing protein (BPI) to 1.7 A. BPI has two domains with the same fold, but with little sequence similarity. To understand the similarity in structure of the two domains, we compare the corresponding residue positions in the two domains by the method of 3D-1D profiles. A 3D-1D profile is a string formed by assigning each position in the 3D structure to one of 18 environment classes. The environment classes are defined by the local secondary structure, the area of the residue which is buried from solvent, and the fraction of the area buried by polar atoms. A structural alignment between the two BPI domains was used to compare the 3D-1D environments of structurally equivalent positions. Greater than 31% of the aligned positions have conserved 3D-1D environments, but only 13% have conserved residue identities. Analysis of the 3D-1D environmentally conserved positions helps to identify pairs of residues likely to be important in conserving the fold, regardless of the residue similarity. We find examples of 3D-1D environmentally conserved positions with dissimilar residues which nevertheless play similar structural roles. To generalize our findings, we analyzed four other proteins with similar structures yet dissimilar sequences. Together, these examples show that aligned pairs of dissimilar residues often share similar structural roles, stabilizing dissimilar sequences in the same fold.
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Affiliation(s)
- G Kleiger
- UCLA-DOE Laboratory of Structural Biology and Molecular Medicine, Molecular Biology Institute, Los Angeles, CA, 90095-1570, USA
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