Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Posttranslational modification of substrates by the small ubiquitin-like modifier, SUMO, regulates diverse biological processes, including transcription, DNA repair, nucleocytoplasmic trafficking, and chromosome segregation. SUMOylation is reversible, and several mammalian homologs of the yeast SUMO-specific protease Ulp1, termed SENPs, have been identified. We demonstrate here that SENP5, a previously uncharacterized Ulp1 homolog, has SUMO C-terminal hydrolase and SUMO isopeptidase activities. In contrast to other SENPs, the C-terminal catalytic domain of SENP5 preferentially processed SUMO-3 compared to SUMO-1 precursors and preferentially removed SUMO-2 and SUMO-3 from SUMO-modified RanGAP1 in vitro. In cotransfection assays, SENP5 preferentially reduced high-molecular-weight conjugates of SUMO-2 compared to SUMO-1 in vivo. Full-length SENP5 localized to the nucleolus. Deletion of the noncatalytic N-terminal domain led to loss of nucleolar localization and increased de-SUMOylation activity in vivo. Knockdown of SENP5 by RNA interference resulted in increased levels of SUMO-1 and SUMO-2/3 conjugates, inhibition of cell proliferation, defects in nuclear morphology, and appearance of binucleate cells, revealing an essential role for SENP5 in mitosis and/or cytokinesis. These findings establish SENP5 as a SUMO-specific protease required for cell division and suggest that mechanisms involving both the catalytic and noncatalytic domains determine the distinct substrate specificities of the mammalian SUMO-specific proteases.
Mol Cell Biol 2006 Jun
PMID:The SUMO-specific protease SENP5 is required for cell division. 1673 15

Protein Prp8 interacts with several other spliceosomal proteins, snRNAs, and the pre-mRNA and thereby organizes the active site(s) of the spliceosome. The DEAD-box protein Brr2 and the GTPase Snu114 bind to the Prp8 C terminus, a region where mutations in human Prp8 are linked to the RP13 form of Retinitis pigmentosa. We show crystallographically that the C-terminal domain of yeast Prp8p exhibits a Jab1/MPN-like core known from deubiquitinating enzymes. Insertions and terminal appendices are grafted onto this core, covering a putative isopeptidase center whose metal binding site is additionally impaired. Targeted yeast-two-hybrid analyses show that the RP13-linked region in the C-terminal appendix of human Prp8 is essential for binding of human Brr2 and Snu114, and that RP13 point mutations in this fragment weaken these interactions. We conclude that the expanded Prp8 Jab1/MPN domain represents a pseudoenzyme converted into a protein-protein interaction platform and that dysfunction of this platform underlies Retinitis pigmentosa.
Mol Cell 2007 Feb 23
PMID:Structure of a multipartite protein-protein interaction domain in splicing factor prp8 and its link to retinitis pigmentosa. 1731 32

Posttranslational modification by ubiquitin controls multiple cellular functions and is counteracted by the activities of deubiquitinating enzymes. UBPy (USP8) is a growth-regulated ubiquitin isopeptidase that interacts with the HRS-STAM complex. Using Cre-loxP-mediated gene targeting in mice, we show that lack of UBPy results in embryonic lethality, whereas its conditional inactivation in adults causes fatal liver failure. The defect is accompanied by a strong reduction or absence of several growth factor receptor tyrosine kinases (RTKs), like epidermal growth factor receptor, hepatocyte growth factor receptor (c-met), and ERBB3. UBPy-deficient cells exhibit aberrantly enlarged early endosomes colocalizing with enhanced ubiquitination and have reduced levels of HRS and STAM2. Congruently immortalized cells gradually stop proliferation upon induced deletion of UBPy. These results unveil a central and nonredundant role of UBPy in growth regulation, endosomal sorting, and the control of RTKs in vivo.
Mol Cell Biol 2007 Jul
PMID:Essential role of ubiquitin-specific protease 8 for receptor tyrosine kinase stability and endocytic trafficking in vivo. 1745 57

The BUZ/Znf-UBP domain is a distinct ubiquitin-binding module found in the cytoplasmic deacetylase HDAC6, the E3 ubiquitin ligase BRAP2/IMP, and a subfamily of deubiquitinating enzymes. Here, we report the solution structure of the BUZ domain of Ubp-M, a ubiquitin-specific protease, and its interaction with ubiquitin. Unlike the BUZ domain from isopeptidase T (isoT) that contains a single zinc finger, the Ubp-M BUZ domain features three zinc-binding sites consisting of 12 residues. These zinc ligands form a pair of cross-braced ring fingers encapsulated within a third zinc finger in the primary structure. In contrast to isoT, which can form an N-terminal loop swapped dimer in the crystal state, the formation of additional zinc fingers in the Ubp-M BUZ domain restricts its N-terminal loop to intra-domain interactions. The ubiquitin-binding site of the Ubp-M BUZ domain is mapped to the highly conserved, concave surface formed by the alpha 3 helix and the central beta-sheet. We further show that this site binds to the C-terminal tail of free ubiquitin, and corresponding peptides display essentially the same binding affinities as full-length ubiquitin does for the Ubp-M BUZ domain. However, modification of the G76(Ub) carboxylate group either by a peptide or isopeptide bond abolishes BUZ-domain interaction. The unique ubiquitin-recognition mode of the BUZ domain family suggests that they may function as "sensors" of free ubiquitin in cells to achieve regulatory roles in many aspects of ubiquitin-dependent processes.
J Mol Biol 2007 Jul 06
PMID:Solution structure of the Ubp-M BUZ domain, a highly specific protein module that recognizes the C-terminal tail of free ubiquitin. 1751 43

The 26S proteasome is a large protein complex involved in protein degradation. We have shown previously that the PSMD7/Mov34 subunit of the human proteasome contains a proteolytically resistant MPN domain. MPN domain family members comprise subunits of the proteasome, COP9-signalosome and translation initiation factor 3 complexes. Here, the crystal structure of two C-terminally truncated proteins, MPN 1-186 and MPN 1-177, were solved to 1.96 and 3.0 A resolution, respectively. MPN 1-186 is formed by nine beta-strands surrounded by three alpha-helices plus a fourth alpha-helix at the C terminus. This final alpha-helix emerges from the domain core and folds along with a symmetrically related subunit, typical of a domain swap. The crystallographic dimer is consistent with size-exclusion chromatography and DLS analysis showing that MPN 1-186 is a dimer in solution. MPN 1-186 shows an overall architecture highly similar to the previously reported crystal structure of the Archaeal MPN domain AfJAMM of Archaeoglobus fulgidus. However, previous structural and biophysical analyses have shown that neither MPN 1-186 nor full-length human Mov34 bind metal, in opposition to the zinc-binding AfJAMM structures. The zinc ligand residues observed in AfJAMM are conserved in the yeast Rpn11 proteasome and Csn5 COP-signalosome subunits, which is consistent with the isopeptidase activity described for these proteins. The results presented here show that, although the MPN domain of Mov34 shows a typical metalloprotease fold, it is unable to coordinate a metal ion. This finding and amino acid sequence comparisons can explain why the MPN-containing proteins Mov34/PSMD7, RPN8, Csn6, Prp8p and the translation initiation factor 3 subunits f and h do not show catalytic isopeptidase activity, allowing us to propose the hypothesis that in these proteins the MPN domain has a primarily structural function.
J Mol Biol 2007 Jul 27
PMID:The crystal structure of the human Mov34 MPN domain reveals a metal-free dimer. 1755 75

The broadly conserved Sir2 NAD(+)-dependent deacetylase is required for chromatin silencing. Here we report the discovery of physical and functional links between Sir2 and Slx5 (Hex3), a RING domain protein and subunit of the Slx5/8 complex, [corrected] which is a ubiquitin E3 ligase that targets sumoylated proteins. Slx5 interacted with Sir2 by two-hybrid and glutathione S-transferase-binding assays and was found to promote silencing of genes at telomeric or ribosomal DNA (rDNA) loci. However, deletion of SLX5 had no detectable effect on the distribution of silent chromatin components and only slightly altered the deacetylation of histone H4 lysine 16 at the telomere. In vivo assays indicated that Sir2-dependent silencing was functionally intact in the absence of Slx5. Although no previous reports suggest that Sir2 contributes to the fitness of yeast populations, we found that Sir2 was required for maximal growth in slx5Delta mutant cells. A similar requirement was observed for mutants of the SUMO isopeptidase Ulp2/Smt4. The contribution of Sir2 to optimal growth was not due to known Sir2 roles in mating-type determination or rDNA maintenance but was connected to a role of sumoylation in transcriptional silencing. These results indicate that Sir2 and Slx5 jointly contribute to transcriptional silencing and robust cellular growth.
Mol Cell Biol 2008 Feb
PMID:Slx5 promotes transcriptional silencing and is required for robust growth in the absence of Sir2. 1808 79

Parkinson's disease (PD) is a neurodegenerative disorder characterized by loss of dopaminergic neurons. The I93M mutation in ubiquitin C-terminal hydrolase L1 (UCH-L1) is associated with familial PD, and we have previously shown that the I93M UCH-L1-transgenic mice exhibit dopaminergic cell loss. Over 90% of neurodegenerative diseases, including PD, occur sporadically. However, the molecular mechanisms underlying sporadic PD as well as PD associated with I93M UCH-L1 are largely unknown. UCH-L1 is abundant (1-5% of total soluble protein) in the brain and is a major target of oxidative/carbonyl damage associated with sporadic PD. As well, abnormal microtubule dynamics and tubulin polymerization are associated with several neurodegenerative diseases including frontotemporal dementia and parkinsonism linked to chromosome 17. Here we show that familial PD-associated mutant UCH-L1 and carbonyl-modified UCH-L1 display shared aberrant properties: compared with wild-type UCH-L1, they exhibit increased insolubility and elevated interactions with multiple proteins, which are characteristics of several neurodegenerative diseases-linked mutants. Circular dichroism analyses suggest similar structural changes in both UCH-L1 variants. We further report that one of the proteins interacting with UCH-L1 is tubulin, and that aberrant interaction of mutant or carbonyl-modified UCH-L1 with tubulin modulates tubulin polymerization. These findings may underlie the toxic gain of function by mutant UCH-L1 in familial PD. Our results also suggest that the carbonyl modification of UCH-L1 and subsequent abnormal interactions of carbonyl-modified UCH-L1 with multiple proteins, including tubulin, constitute one of the causes of sporadic PD.
Hum Mol Genet 2008 May 15
PMID:Aberrant molecular properties shared by familial Parkinson's disease-associated mutant UCH-L1 and carbonyl-modified UCH-L1. 1825 96

Oxidative stress contributes to the development of neurodegenerative diseases. DJ-1, a protein genetically linked to Parkinson's disease (PD), has been implicated in oxidative stress defense and transcriptional regulation. However, it is unclear whether these two aspects of the DJ-1 function are connected. Here, we show that the inactivation of DJ-1 causes decreased expression of the human MnSOD. DJ-1 stimulates the activity of a master regulator of mitochondrial biogenesis and stress response, peroxisome proliferator-activated receptor-gamma co-activator 1alpha (PGC-1alpha), in the transcription of the MnSOD. Although DJ-1 does not interact with PGC-1alpha directly, it inhibits the SUMOylation of a transcriptional repressor, pyrimidine tract-binding protein-associated splicing factor (PSF). PSF binds PGC-1alpha and suppresses its transcriptional activity. In contrast, a SUMOylation-deficient PSF mutant exhibits reduced binding to PGC-1alpha and promotes its activity. SUMO-specific isopeptidase SENP-1 further enhances the synergy between DJ-1 and PGC-1alpha, whereas an SUMO E3 ligase protein inhibitor of activated STAT Y completely blocks the synergy. Conversely, oxidative modification renders DJ-1 unable to inhibit SUMOylation, resulting in attenuated transcriptional synergy between DJ-1 and PGC-1alpha. Therefore, our results validate DJ-1 as a transcriptional regulator in mitochondrial oxidative stress response and imply that the oxidation-mediated functional impairment of DJ-1 leads to gradual dysregulation of the SUMO pathway. Consequent abnormal mitochondrial gene expression may contribute to the development of sporadic PD.
Hum Mol Genet 2008 Nov 01
PMID:Synergistic activation of the human MnSOD promoter by DJ-1 and PGC-1alpha: regulation by SUMOylation and oxidation. 1868 99

The ubiquitin-like SUMO system controls cellular key functions, and several lines of evidence point to a critical role of SUMO for mitotic progression. However, in mammalian cells mitotic substrates of sumoylation and the regulatory components involved are not well defined. Here, we identify Borealin, a component of the chromosomal passenger complex (CPC), as a mitotic target of SUMO. The CPC, which additionally comprises INCENP, Survivin, and Aurora B, regulates key mitotic events, including chromosome congression, the spindle assembly checkpoint, and cytokinesis. We show that Borealin is preferentially modified by SUMO2/3 and demonstrate that the modification is dynamically regulated during mitotic progression, peaking in early mitosis. Intriguingly, the SUMO ligase RanBP2 interacts with the CPC, stimulates SUMO modification of Borealin in vitro, and is required for its modification in vivo. Moreover, the SUMO isopeptidase SENP3 is a specific interaction partner of Borealin and catalyzes the removal of SUMO2/3 from Borealin. These data thus delineate a mitotic SUMO2/3 conjugation-deconjugation cycle of Borealin and further assign a regulatory function of RanBP2 and SENP3 in the mitotic SUMO pathway.
Mol Biol Cell 2009 Jan
PMID:RanBP2 and SENP3 function in a mitotic SUMO2/3 conjugation-deconjugation cycle on Borealin. 1894 85

To measure rates of sumoylation and isopeptidase cleavage in vitro, we developed an enzyme assay that is based on fluorescence resonance energy transfer (FRET). FRET is a process by which the excited state energy of a fluorescent donor molecule is transferred to an acceptor molecule. Efficient energy transfer requires very close proximity, and can therefore be used as a read-out for covalent and non-covalent protein interactions. The assay described here uses bacterially expressed and purified YFP-SUMO-1 and CFP-RanGAP1 as model substrates that are covalently coupled in the presence of recombinant SUMO E1 and E2 enzymes and ATP. Reactions of 25 microl volume, set up in 384-wells plates, give sufficient signal for analysis. Consequently, this assay requires very low amounts of recombinant proteins and allows measurement of time courses in high-throughput format.
Methods Mol Biol 2009
PMID:An in vitro FRET-based assay for the analysis of SUMO conjugation and isopeptidase cleavage. 1910 22


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