Structural basis for autoinhibition and phosphorylation-dependent activation of c-Cbl

Dou, Haoran; Buetow, Lori; Höck, A.; Sibbet, Gary; Vousden, Karen H.; Huang, Danny T.

doi:10.1038/nsmb.2231

Cited by 155 publications

(257 citation statements)

References 50 publications

(76 reference statements)

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“…The interplay between ubiquitination and phosphorylation is quite extensive, can occur at the level of the modifying enzymes and/or substrates, and each PTM is capable of antagonizing or promoting the functioning of the other (Hunter, 2007;Swaney et al, 2013). Phosphorylation of the E3 ligase can regulate function in different ways, such as activating the enzyme to allow for substrate ubiquitination, promoting self-ubiquitination to inhibit activity, or switching substrate specificity (Yang et al, 2006;Cheng et al, 2011;Dou et al, 2012). Phosphorylation of the substrate can promote ubiquitination via the creation of phosphodegrons, which are phosphorylated residues that allow for recognition by the E3 ligase (Hunter, 2007).…”

Section: Discussionmentioning

confidence: 99%

The RING-Type E3 Ligase XBAT35.2 Is Involved in Cell Death Induction and Pathogen Response

et al. 2017

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XBAT35 belongs to a subfamily of Arabidopsis (Arabidopsis thaliana) RING-type E3s that are similar in domain architecture to the rice (Oryza sativa) XA21 Binding Protein3, a defense protein. The XBAT35 transcript undergoes alternative splicing to produce two protein isoforms, XBAT35.1 and XBAT35.2. Here, we demonstrate that XBAT35.2 localizes predominantly to the Golgi and is involved in cell death induction and pathogen response. XBAT35.2, but not XBAT35.1, was found to trigger cell death when overexpressed in tobacco (Nicotiana benthamiana) leaves and does so in a manner that requires its RING domain. Loss of XBAT35 gene function disrupts the plant's ability to defend against pathogen attack, whereas overexpression of XBAT35.2 enhances resistance to pathogens. XBAT35.2 was found to be unstable and promotes its own degradation, suggesting self-regulation. Inoculation with virulent and avirulent strains of the bacterial pathogen Pseudomonas syringae pv tomato DC3000 results in a drastic reduction in the levels of ubiquitinated XBAT35.2 and an increase in the abundance of the E3. This implies that pathogen infection prohibits XBAT35.2 self-regulation and stabilizes the E3. In agreement with a role in defending against pathogens, XBAT35.2 interacts with defense-related Accelerated Cell Death11 (ACD11) in planta and promotes the proteasome-dependent turnover of ACD11 in cell-free degradation assays. In accordance with regulation by a stabilized XBAT35.2, the levels of ubiquitinated ACD11 increased considerably, and the abundance of ACD11 was reduced following pathogen infection. In addition, treatment of transgenic seedlings with a proteasome inhibitor results in the accumulation of ACD11, confirming proteasome-dependent degradation. Collectively, these results highlight a novel role for XBAT35.2 in cell death induction and defense against pathogens.Posttranslational modification (PTM) via ubiquitination plays essential regulatory roles in all eukaryotic cells. The selective attachment of ubiquitin serves as a versatile modification that regulates protein activity, abundance, sorting, and localization (Deshaies and Joazeiro, 2009;Komander and Rape, 2012). This versatility places ubiquitination at the center of numerous cellular processes and allows for the regulation of growth, development, and responses to various environmental stimuli. Ubiquitination is accomplished through the sequential action of three enzymes: E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3 (ubiquitin ligase). Ubiquitin conjugation begins with the activation of ubiquitin molecules by E1, which is then transferred to E2, forming a thioester-linked E2-ubiquitin intermediate. Finally, E3 mediates the transfer of ubiquitin from the E2-ubiquitin intermediate to the substrate. The covalent attachment of ubiquitin to the substrate is usually accomplished via the formation of an isopeptide bond between the C-terminal Gly of ubiquitin and an internal lysine (Lys) of the substrate. Substrate modifications include the

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Section: Discussionmentioning

confidence: 99%

The RING-Type E3 Ligase XBAT35.2 Is Involved in Cell Death Induction and Pathogen Response

et al. 2017

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“…Elegant experiments by Plechanovová et al (2012) and Dou et al (2012b) showed that the E2 contacts a single protomer of the dimeric E3 (RNF4 and Birc7, respectively), while ubiquitin is folded back onto the E2 via contacts from both RING molecules. Mutational analysis of the involved residues supported a mechanism by which both protomers cooperate for ubiquitin priming (Plechanovová et al, 2011).…”

Section: Dimerization and E3 Ligase Activitymentioning

confidence: 99%

“…However, independently of the signaling pathway (e.g., apoptosis or innate immunity), an intact RING mediating dimerization, and thus also autoubiquitination, is required. Similarly, activation of cCBL triggers its ubiquitinating activity toward its substrates and itself, leading to a rapid decrease of both its levels and the substrates (Ryan et al, 2006;Dou et al, 2012b).…”

Section: Autoubiquitination a Mechanism Of Self-regulation?mentioning

confidence: 99%

Changes in PUB22 Ubiquitination Modes Triggered by MITOGEN-ACTIVATED PROTEIN KINASE3 Dampen the Immune Response

et al. 2017

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Crosstalk between posttranslational modifications, such as ubiquitination and phosphorylation, play key roles in controlling the duration and intensity of signaling events to ensure cellular homeostasis. However, the molecular mechanisms underlying the regulation of negative feedback loops remain poorly understood. Here, we uncover a pathway in Arabidopsis thaliana by which a negative feedback loop involving the E3 ubiquitin ligase PUB22 that dampens the immune response is triggered by MITOGEN-ACTIVATED PROTEIN KINASE3 (MPK3), best known for its function in the activation of signaling. PUB22's stability is controlled by MPK3-mediated phosphorylation of residues localized in and adjacent to the E2 docking domain. We show that phosphorylation is critical for stabilization by inhibiting PUB22 oligomerization and, thus, autoubiquitination. The activity switch allows PUB22 to dampen the immune response. This regulatory mechanism also suggests that autoubiquitination, which is inherent to most single unit E3s in vitro, can function as a self-regulatory mechanism in vivo.

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“…(C) Activation of Cbl via a conformational change triggered by tyrosine phosphorylation of the LHR linker region. Shown here is the structure, in surface representation, of a c-Cbl-E2-substrate peptide complex in an inactive conformation (left, PDB code 1FBV [36]) or when activated through phosphorylation of Tyr371 in the linker region (right, PDB code 4A4C [37]). The E2 and RING domains are blue and magenta, respectively.…”

Section: Py Substrate Binding and Ubiquitination By Cbl Proteinsmentioning

confidence: 99%

Cell Regulation by Phosphotyrosine-Targeted Ubiquitin Ligases

Cooper

Kaneko

2015

Molecular and Cellular Biology

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Three classes of E3 ubiquitin ligases, members of the Cbl, Hakai, and SOCS-Cul5-RING ligase families, stimulate the ubiquitination of phosphotyrosine-containing proteins, including receptor and nonreceptor tyrosine kinases and their phosphorylated substrates. Because ubiquitination frequently routes proteins for degradation by the lysosome or proteasome, these E3 ligases are able to potently inhibit tyrosine kinase signaling. Their loss or mutational inactivation can contribute to cancer, autoimmunity, or endocrine disorders, such as diabetes. However, these ligases also have biological functions that are independent of their ubiquitination activity. Here we review relevant literature and then focus on more-recent developments in understanding the structures, substrates, and pathways through which the phosphotyrosine-specific ubiquitin ligases regulate diverse aspects of cell biology. Phosphorylation and ubiquitination are among the commonest and best-studied posttranslational modifications of proteins. A phosphate group or ubiquitin molecule can trigger or obstruct protein-protein interactions, alter subcellular localization, stabilize a particular protein conformation, or have myriad other effects. Phosphorylation is directly catalyzed by protein kinases, but ubiquitination is more complex, requiring sequential activity of E1, E2, and E3 ubiquitin-activating, -conjugating, and -ligating enzymes (1-5). E3 ubiquitin ligases fall into two major groups: HECT domain ligases receive ubiquitin from an E2 enzyme and transfer it to a bound substrate, while RING-type ligases position an E2-ubiquitin conjugate near a substrate protein to facilitate ubiquitin transfer. Both phosphorylation and ubiquitination are reversible; protein phosphorylation is reversed by protein phosphatases and ubiquitination by deubiquitinating enzymes (DUBs) (6-8). Therefore, both phosphorylation/dephosphorylation and ubiquitination/deubiquitination can allow repeated cycles of protein modification. Reversible ubiquitination is particularly important in DNA repair and NF-B signaling. However, many ubiquitination events lead irreversibly to protein destruction, allowing regulation of protein turnover. For example, K48 polyubiquitin chains primarily route cytosolic proteins to the proteasome, while modification of many Lys residues with single ubiquitin molecules (multimonoubiquitination) has several functions, including routing membrane proteins for destruction in the lysosome (9-11). The irreversibility of proteolysis means that the ubiquitin-proteasome and ubiquitin-lysosome pathways directly control protein life spans.Protein phosphorylation and ubiquitination cross talk at many levels (12). In this review, we focus on situations where phosphorylation of a substrate creates a binding site for an E3 ligase, rendering ubiquitination dependent on prior phosphorylation of that substrate (13). Such phosphorylation-dependent substrate selection has particular importance because it can layer negative feedback onto an otherwise reversible phosphoryla...

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Structural basis for autoinhibition and phosphorylation-dependent activation of c-Cbl

Cited by 155 publications

References 50 publications

The RING-Type E3 Ligase XBAT35.2 Is Involved in Cell Death Induction and Pathogen Response

The RING-Type E3 Ligase XBAT35.2 Is Involved in Cell Death Induction and Pathogen Response

Changes in PUB22 Ubiquitination Modes Triggered by MITOGEN-ACTIVATED PROTEIN KINASE3 Dampen the Immune Response

Cell Regulation by Phosphotyrosine-Targeted Ubiquitin Ligases

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