scholarly journals Formation of Bombyx mori nucleopolyhedrovirus IE2 nuclear foci is regulated by the functional domains for oligomerization and ubiquitin ligase activity

2005 ◽  
Vol 86 (3) ◽  
pp. 637-644 ◽  
Author(s):  
Noriko Imai ◽  
Shogo Matsumoto ◽  
WonKyung Kang
Keyword(s):  
Bombyx Mori ◽  
Ubiquitin Ligase ◽  
Coiled Coil ◽  
Ring Finger ◽  
Functional Domains ◽  
Focus Formation ◽  
Ring Finger Domain ◽  
Coiled Coil Region ◽  
Ubiquitin Ligase Activity ◽  
Nuclear Foci

Baculovirus IE2 functions as a transregulator and is also involved in viral DNA replication. However, the mechanism for these functions remains unknown. It has previously been reported that Bombyx mori nucleopolyhedrovirus (BmNPV) IE2 has a ubiquitin ligase activity that is dependent on the RING finger domain and that IE2 can oligomerize through its C-terminal coiled-coil region. Here, confocal microscopy analysis demonstrated that IE2 formed nuclear foci only during the early phase of infection (2–6 h post-infection). Therefore, it was determined whether the IE2 functional regions described above could affect this characteristic distribution. Transient expression of ie2 also showed focus formation, suggesting that IE2 does not require any other viral factors. IE2 mutants lacking the C-terminal coiled-coil region did not form foci, while a mutant of the RING finger domain showed nuclear foci that appeared larger and brighter than those formed by wild-type IE2. In addition, IE2 exhibited enlarged foci in infected cells following treatment with a proteasome inhibitor, suggesting that foci enlargement resulted from accumulation of IE2 due to inhibition of the ubiquitin-proteasome pathway. These results suggest that BmNPV IE2 oligomerization and ubiquitin ligase activity functional domains regulate nuclear foci formation.

scholarly journals Normal Immune System Development in Mice Lacking the Deltex-1 RING Finger Domain

2005 ◽  
Vol 25 (4) ◽  
pp. 1437-1445 ◽  
Author(s):  
Sébastien Storck ◽  
Frédéric Delbos ◽  
Nicolas Stadler ◽  
Catherine Thirion-Delalande ◽  
Florence Bernex ◽  
...  
Keyword(s):  
B Cell ◽  
Notch Signaling ◽  
Ubiquitin Ligase ◽  
Cell Lineage ◽  
Ring Finger ◽  
Mouse Development ◽  
Ring Finger Domain ◽  
Ubiquitin Ligase Activity ◽  
Immune System Development ◽  
Cell Commitment

ABSTRACT The Notch signaling pathway controls several cell fate decisions during lymphocyte development, from T-cell lineage commitment to the peripheral differentiation of B and T lymphocytes. Deltex-1 is a RING finger ubiquitin ligase which is conserved from Drosophila to humans and has been proposed to be a regulator of Notch signaling. Its pattern of lymphoid expression as well as gain-of-function experiments suggest that Deltex-1 regulates both B-cell lineage and splenic marginal-zone B-cell commitment. Deltex-1 was also found to be highly expressed in germinal-center B cells. To investigate the physiological function of Deltex-1, we generated a mouse strain lacking the Deltex-1 RING finger domain, which is essential for its ubiquitin ligase activity. Deltex-1Δ/Δ mice were viable and fertile. A detailed histological analysis did not reveal any defects in major organs. T- and B-cell development was normal, as were humoral responses against T-dependent and T-independent antigens. These data indicate that the Deltex-1 ubiquitin ligase activity is dispensable for mouse development and immune function. Possible compensatory mechanisms, in particular those from a fourth Deltex gene identified during the course of this study, are also discussed.

scholarly journals IE1 and hr facilitate the localization of Bombyx mori nucleopolyhedrovirus ORF8 to specific nuclear sites

2005 ◽  
Vol 86 (11) ◽  
pp. 3031-3038 ◽  
Author(s):  
WonKyung Kang ◽  
Noriko Imai ◽  
Yu Kawasaki ◽  
Toshihiro Nagamine ◽  
Shogo Matsumoto
Keyword(s):  
Bombyx Mori ◽  
Fluorescent Protein ◽  
Coiled Coil ◽  
Terminal Region ◽  
Mutant Protein ◽  
Yeast Two Hybrid ◽  
Focus Formation ◽  
Coiled Coil Domain ◽  
Nuclear Foci ◽  
Two Hybrid

The Bombyx mori nucleopolyhedrovirus (BmNPV) ORF8 protein has previously been reported to colocalize with IE1 to specific nuclear sites during infection. Transient expression of green fluorescent protein (GFP)-fused ORF8 showed the protein to have cytoplasmic localization, but following BmNPV infection the protein formed foci, suggesting that ORF8 requires some other viral factor(s) for this. Therefore, interacting factors were looked for using the yeast two-hybrid system and IE1 was identified. We mapped the interacting region of ORF8 using a yeast two-hybrid assay. An N-terminal region (residues 1–110) containing a predicted coiled-coil domain interacted with IE1, while a truncated N-terminal region (residues 1–78) that lacks this domain did not. In addition, a protein with a complete deletion of the N-terminal region failed to interact with IE1. These results suggest that the ORF8 N-terminal region containing the coiled-coil domain is required for the interaction with IE1. Next, whether IE1 plays a role in ORF8 localization was investigated. In the presence of IE1, GFP-ORF8 localized to the nucleus. In addition, cotransfection with a plasmid expressing IE1 and a plasmid containing the hr3 element resulted in nuclear foci formation. A GFP-fused ORF8 mutant protein containing the coiled-coil domain, previously shown to interact with IE1, also formed nuclear foci in the presence of IE1 and hr3. However, ORF8 mutant proteins that did not interact with IE1 failed to form nuclear foci. In contrast to wild-type IE1, focus formation was not observed for an IE1 mutant protein that was deficient in hr binding. These results suggest that IE1 and hr facilitate the localization of BmNPV ORF8 to specific nuclear sites.

scholarly journals The RING Finger Domain of Varicella-Zoster Virus ORF61p Has E3 Ubiquitin Ligase Activity That Is Essential for Efficient Autoubiquitination and Dispersion of Sp100-Containing Nuclear Bodies

2010 ◽  
Vol 84 (13) ◽  
pp. 6861-6865 ◽  
Author(s):  
Matthew S. Walters ◽  
Christos A. Kyratsous ◽  
Saul J. Silverstein
Keyword(s):  
Varicella Zoster Virus ◽  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Ring Finger ◽  
Nuclear Bodies ◽  
Ring Finger Domain ◽  
Varicella Zoster ◽  
Ubiquitin Ligase Activity ◽  
Protein Icp0 ◽  
Simplex Virus

ABSTRACT Varicella zoster virus encodes an immediate-early (IE) protein termed ORF61p that is orthologous to the herpes simplex virus IE protein ICP0. Although these proteins share several functional properties, ORF61p does not fully substitute for ICP0. The greatest region of similarity between these proteins is a RING finger domain. We demonstrate that disruption of the ORF61p RING finger domain by amino acid substitution (Cys19Gly) alters ORF61p intranuclear distribution and abolishes ORF61p-mediated dispersion of Sp100-containing nuclear bodies. In addition, we demonstrate that an intact ORF61p RING finger domain is necessary for E3 ubiquitin ligase activity and is required for autoubiquitination and regulation of protein stability.

scholarly journals Disruption of PML Subnuclear Domains by the Acidic IE1 Protein of Human Cytomegalovirus Is Mediated through Interaction with PML and May Modulate a RING Finger-Dependent Cryptic Transactivator Function of PML

1998 ◽  
Vol 18 (8) ◽  
pp. 4899-4913 ◽  
Author(s):  
Jin-Hyun Ahn ◽  
Edward J. Brignole ◽  
Gary S. Hayward
Keyword(s):  
Human Cytomegalovirus ◽  
Coiled Coil ◽  
Ring Finger ◽  
Physical Interaction ◽  
Mutant Form ◽  
Metaphase Chromosomes ◽  
Ring Finger Domain ◽  
Coiled Coil Region ◽  
Acidic Region ◽  
Two Hybrid

ABSTRACT Both of the major immediate-early (IE) proteins IE1 and IE2 of human cytomegalovirus (HCMV) as well as input viral DNA and sites of viral IE transcription colocalize with or adjacent to punctate PML domains (PML oncogenic domains [PODs] or nuclear domain 10) in the nucleus within the first few hours after infection of permissive human fibroblasts. However, colocalization of IE1 and PML in PODs is only transient, with both proteins subsequently redistributing into a nuclear diffuse form. These processes are believed to promote efficient viral IE transcription and initiation of DNA synthesis especially at low multiplicities of infection. To examine the mechanism of PML displacement by IE1, we carried out indirect immunofluorescence assay experiments with plasmids expressing intact or deleted forms of PML and IE1 in DNA-transfected cells. The results demonstrated that deletion of the C-terminal acidic region of IE1 uncouples the requirements for displacement of both endogenous and coexpressed PML from those needed to target to the PODs. Mutant PML proteins containing either a Cys point mutation within the N-terminal RING finger domain or a small deletion (of positions 281 to 304) within the coiled-coil region did not localize to the PODs but instead gave a nuclear diffuse distribution, similar to that produced by intact PML in the presence of IE1. Endogenous PML also colocalized with IE1 in metaphase chromosomes in HCMV or recombinant adenovirus type 5-IE1-infected HF cells undergoing mitosis, implying that there may be a direct physical interaction between IE1 and PML. Indeed, a specific interaction between IE1 and PML was observed in a yeast two-hybrid assay, and the strength of this interaction was comparable to that of IE2 with the retinoblastoma protein. The RING finger mutant form of PML showed a threefold-lower interaction with IE1 in the yeast system, and deletion of the N-terminal RING finger domain of PML abolished the interaction. Consistent with the IFA results, a mutant IE1 protein that lacks the C-terminal acidic region was sufficient for interaction with PML in the yeast system. The two-hybrid interaction assay also showed that both the N-terminal RING finger domain and the intact coiled-coil region of PML are required cooperatively for efficient self-interactions involving dimerization or oligomerization. Furthermore, truncated or deleted GAL4/PML fusion proteins that retained the RING finger domain but lacked the intact coiled-coil region displayed an unmasked cryptic transactivator function in both yeast and mammalian cells, and the RING finger mutation abolished this transactivation property of PML. Therefore, we suggest that a direct interaction between IE1 and the N-terminal RING finger domain of PML may inhibit oligomerization and protein-protein complex formation by PML, leading to displacement of PML and IE1 from the PODs, and that this interaction may also modulate a putative conditional transactivator function of PML.

scholarly journals Cbl-c Ubiquitin Ligase Activity Is Increased via the Interaction of Its RING Finger Domain with a LIM Domain of the Paxillin Homolog, Hic 5

PLoS ONE ◽  
2012 ◽  
Vol 7 (11) ◽  
pp. e49428 ◽  
Author(s):  
Philip E. Ryan ◽  
Stephen C. Kales ◽  
Rajgopal Yadavalli ◽  
Marion M. Nau ◽  
Han Zhang ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Ring Finger ◽  
Lim Domain ◽  
Ring Finger Domain ◽  
Ubiquitin Ligase Activity

scholarly journals The RBCC GeneRFP2(Leu5) Encodes a Novel Transmembrane E3 Ubiquitin Ligase Involved in ERAD

2007 ◽  
Vol 18 (5) ◽  
pp. 1670-1682 ◽  
Author(s):  
Mikael Lerner ◽  
Martin Corcoran ◽  
Diana Cepeda ◽  
Michael L. Nielsen ◽  
Roman Zubarev ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Fluorescent Protein ◽  
Transmembrane Domain ◽  
Yellow Fluorescent Protein ◽  
E3 Ubiquitin Ligase ◽  
Coiled Coil ◽  
Ring Finger ◽  
Ubiquitin Ligase Activity

RFP2, a gene frequently lost in various malignancies, encodes a protein with RING finger, B-box, and coiled-coil domains that belongs to the RBCC/TRIM family of proteins. Here we demonstrate that Rfp2 is an unstable protein with auto-polyubiquitination activity in vivo and in vitro, implying that Rfp2 acts as a RING E3 ubiquitin ligase. Consequently, Rfp2 ubiquitin ligase activity is dependent on an intact RING domain, as RING deficient mutants fail to drive polyubiquitination in vitro and are stabilized in vivo. Immunopurification and tandem mass spectrometry enabled the identification of several putative Rfp2 interacting proteins localized to the endoplasmic reticulum (ER), including valosin-containing protein (VCP), a protein indispensable for ER-associated degradation (ERAD). Importantly, we also show that Rfp2 regulates the degradation of the known ER proteolytic substrate CD3-δ, but not the N-end rule substrate Ub-R-YFP (yellow fluorescent protein), establishing Rfp2 as a novel E3 ligase involved in ERAD. Finally, we show that Rfp2 contains a C-terminal transmembrane domain indispensable for its localization to the ER and that Rfp2 colocalizes with several ER-resident proteins as analyzed by high-resolution immunostaining. In summary, these data are all consistent with a function for Rfp2 as an ERAD E3 ubiquitin ligase.

scholarly journals Oligomerization-primed coiled-coil domain interaction with Ubc13 confers processivity to TRAF6 ubiquitin ligase activity

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Lin Hu ◽  
Jiafeng Xu ◽  
Xiaomei Xie ◽  
Yiwen Zhou ◽  
Panfeng Tao ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Coiled Coil ◽  
Domain Interaction ◽  
Coiled Coil Domain ◽  
Ubiquitin Ligase Activity

scholarly journals The AAA+ ATPase/ubiquitin ligase mysterin stabilizes cytoplasmic lipid droplets

2019 ◽  
Vol 218 (3) ◽  
pp. 949-960 ◽  
Author(s):  
Munechika Sugihara ◽  
Daisuke Morito ◽  
Shiori Ainuki ◽  
Yoshinobu Hirano ◽  
Kazutoyo Ogino ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Lipid Droplets ◽  
Ring Finger ◽  
Unknown Etiology ◽  
Cerebrovascular Disorder ◽  
Intracellular Protein ◽  
Ring Finger Domain ◽  
Genetic Studies ◽  
Aaa Atpase ◽  
Potential Link

Mysterin, also known as RNF213, is an intracellular protein that forms large toroidal oligomers. Mysterin was originally identified in genetic studies of moyamoya disease (MMD), a rare cerebrovascular disorder of unknown etiology. While mysterin is known to exert ubiquitin ligase and putative mechanical ATPase activities with a RING finger domain and two adjacent AAA+ modules, its biological role is poorly understood. Here, we report that mysterin is targeted to lipid droplets (LDs), ubiquitous organelles specialized for neutral lipid storage, and markedly increases their abundance in cells. This effect was exerted primarily through specific elimination of adipose triglyceride lipase (ATGL) from LDs. The ubiquitin ligase and ATPase activities of mysterin were both important for its proper LD targeting. Notably, MMD-related mutations in the ubiquitin ligase domain of mysterin significantly impaired its fat-stabilizing activity. Our findings identify a unique new regulator of cytoplasmic LDs and suggest a potential link between the pathogenesis of MMD and fat metabolism.

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