scholarly journals Detection protein ubiquitination level using immunoprecipitation and western blot methods

2019 ◽  
Author(s):  
Xiwei Liu ◽  
Xiangbo Meng ◽  
Xiwei Liu ◽  
Chenqi Xu
Keyword(s):  
Western Blot ◽  
Protein Ubiquitination

scholarly journals Ubiquitination-activating enzymes UBE1 and UBA6 regulate ubiquitination and expression of cardiac sodium channel Nav1.5

2020 ◽  
Vol 477 (9) ◽  
pp. 1683-1700
Author(s):  
Yushuang Hu ◽  
Xuemei Bai ◽  
Chi Zhang ◽  
Susmita Chakrabarti ◽  
Bo Tang ◽  
...  
Keyword(s):  
Heart Failure ◽  
Western Blot ◽  
Sodium Channel ◽  
Current Density ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Sodium Current ◽  
Pcr Analysis ◽  
Protein Ubiquitination ◽  
Cardiac Sodium Channel

Cardiac sodium channel Nav1.5 is associated with cardiac arrhythmias and heart failure. Protein ubiquitination is catalyzed by an E1–E2–E3 cascade of enzymes. However, the E1 enzyme catalyzing Nav1.5 ubiquitination is unknown. Here, we show that UBE1 and UBA6 are two E1 enzymes regulating Nav1.5 ubiquitination and expression. Western blot analysis and patch-clamping recordings showed that overexpression of UBE1 or UBA6 increased the ubiquitination of Nav1.5 and significantly reduced Nav1.5 expression and sodium current density, and knockdown of UBE1 or UBA6 expression significantly increased Nav1.5 expression and sodium current density in HEK293/Nav1.5 cells. Similar results were obtained in neonatal cardiomyocytes. Bioinformatic analysis predicted two ubiquitination sites at K590 and K591. Mutations of K590 and K591 to K590A and K591A abolished the effects of overexpression or knockdown of UBE1 or UBA6 on Nav1.5 expression and sodium current density. Western blot analysis showed that the effects of UBE1 or UBA6 overexpression on the ubiquitination and expression of Nav1.5 were abolished by knockdown of UBC9, a putative E2 enzyme reported for Nav1.5 ubiquitination by us. Interestingly, real-time RT-PCR analysis showed that the expression level of UBE1, but not UBA6, was significantly up-regulated in ventricular tissues from heart failure patients. These data establish UBE1 and UBA6 as the E1 enzymes involved in Nav1.5 ubiquitination, and suggest that UBE1 and UBA6 regulate ubiquitination of Nav1.5 through UBC9. Our study is the first to reveal the regulatory role of the UBE1 or UBA6 E1 enzyme in the ubiquitination of an ion channel and links UBE1 up-regulation to heart failure.

scholarly journals MKRN1 Ubiquitylates p21 to Protect against Intermittent Hypoxia-Induced Myocardial Apoptosis

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Xue Bai ◽  
Hui Yang ◽  
Jiayuan Pu ◽  
Yan Zhao ◽  
Ying Jin ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Western Blot ◽  
Cell Apoptosis ◽  
Intermittent Hypoxia ◽  
Sleep Apnea Syndrome ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Myocardial Apoptosis ◽  
Protein Ubiquitination ◽  
Obstructive Sleep

Although chronic intermittent hypoxia- (IH-) induced myocardial apoptosis is an established pathophysiological process resulting in a poor prognosis for patients with obstructive sleep apnea syndrome, its underlying mechanism remains unclear. This study is aimed at exploring the role of makorin ring finger protein 1 (MKRN1) in IH-induced myocardial apoptosis and elucidating its molecular activity. First, the GSE2271 dataset was downloaded from the Gene Expression Omnibus database to identify the differentially expressed genes. Then, an SD rat model of IH, together with rat cardiomyocyte H9C2 and human cardiomyocyte AC16 IH models, was constructed. TUNEL, Western blot, and immunohistochemistry assays were used to detect cell apoptosis. Dihydroethidium staining was conducted to analyze the concentration of reactive oxygen species. In addition, RT-qPCR, Western blot, and immunohistochemistry were performed to measure the expression levels of MKRN1 and p21. The direct interaction between MKRN1 and p21 was determined using coimmunoprecipitation and ubiquitination analysis. MKRN1 expression was found to be downregulated in IH rat myocardial tissues as well as in H9C2 and AC16 cells. Upregulated expression of MKRN1 in H9C2 and AC16 cells alleviated the IH-induced reactive oxygen species production and cell apoptosis. Mechanistically, MKRN1 promoted p21 protein ubiquitination and the proteasome pathway degradation to negatively regulate p21 expression. Thus, MKRN1 regulates p21 ubiquitination to prevent IH-induced myocardial apoptosis.

scholarly journals Regulation of Oral Squamous Cell Carcinoma Proliferation Through Crosstalk Between SMAD7 and CYLD

2016 ◽  
Vol 38 (3) ◽  
pp. 1209-1217 ◽  
Author(s):  
Wei-Li Ge ◽  
Jun-Feng Xu ◽  
Jun Hu
Keyword(s):  
Squamous Cell Carcinoma ◽  
Oral Squamous Cell Carcinoma ◽  
Western Blot ◽  
Cell Carcinoma ◽  
Squamous Cell ◽  
Cell Invasion ◽  
Protein Levels ◽  
Protein Ubiquitination ◽  
Cell Conversion ◽  
Cell Invasiveness

Background/Aims: SMAD7 is a key inhibitor of transforming growth factor β (TGFβ) receptor signaling, which regulates the alteration of cancer cell invasiveness through epithelial-mesenchymal cell conversion. Dysfunction of protein ubiquitination plays a critical role in carcinogenesis, whereas the involvement a deubiquitinating enzyme, cylindromatosis gene (CYLD), in the tumor invasion of oral squamous cell carcinoma (OSCC) is unknown. Methods: Here, we studied the role of CYLD in regulation of OSCC cell invasion, using clinic specimens and cell lines. We modified SMAD7 levels in OSCC cells, and examined its effects on CYLD mRNA and protein levels by RT-qPCR and by Western blot, respectively. We also modified CYLD levels in OSCC cells, and examined its effects on SMAD7 mRNA and protein levels by RT-qPCR and by Western blot, respectively. Then, we examined the cell invasiveness in CYLD and/or SMAD7-modified OSCC cells in a transwell cell invasion assay. Results: We found that the levels of CYLD and SMAD7 were significantly decreased in OSCC specimens, compared to the paired normal tissue. Metastatic OSCC appeared to contained lower levels of CYLD and SMAD7. Moreover, CYLD and SMAD7 levels strongly correlated in OSCC specimens. Low CYLD levels were associated with poor patients' survival. Moreover, SMAD did not regulate CYLD, but CYLD regulated the levels of SMAD7 in OSCC cells. Furthermore, CYLD overexpression inhibited SMAD7-mediated cell invasion, while CYLD depletion increased SMAD7-mediated cell invasion in OSCC cells. Conclusion: Suppression of CYLD in OSCC cells may promote SMAD7-mediated cancer invasion. Thus, CYLD appears to be an intriguing therapeutic target to prevent OSCC metastases.

E3 ubiquitin ligases

2005 ◽  
Vol 41 ◽  
pp. 15-30 ◽  
Author(s):  
Helen C. Ardley ◽  
Philip A. Robinson
Keyword(s):  
Protein Complexes ◽  
Loss Of Function ◽  
Direct Role ◽  
Cellular Processes ◽  
Substrate Protein ◽  
Protein Ubiquitination ◽  
C Terminus ◽  
Full Complement ◽  
Spatio Temporal ◽  
Eukaryotic Organisms

The selectivity of the ubiquitin–26 S proteasome system (UPS) for a particular substrate protein relies on the interaction between a ubiquitin-conjugating enzyme (E2, of which a cell contains relatively few) and a ubiquitin–protein ligase (E3, of which there are possibly hundreds). Post-translational modifications of the protein substrate, such as phosphorylation or hydroxylation, are often required prior to its selection. In this way, the precise spatio-temporal targeting and degradation of a given substrate can be achieved. The E3s are a large, diverse group of proteins, characterized by one of several defining motifs. These include a HECT (homologous to E6-associated protein C-terminus), RING (really interesting new gene) or U-box (a modified RING motif without the full complement of Zn2+-binding ligands) domain. Whereas HECT E3s have a direct role in catalysis during ubiquitination, RING and U-box E3s facilitate protein ubiquitination. These latter two E3 types act as adaptor-like molecules. They bring an E2 and a substrate into sufficiently close proximity to promote the substrate's ubiquitination. Although many RING-type E3s, such as MDM2 (murine double minute clone 2 oncoprotein) and c-Cbl, can apparently act alone, others are found as components of much larger multi-protein complexes, such as the anaphase-promoting complex. Taken together, these multifaceted properties and interactions enable E3s to provide a powerful, and specific, mechanism for protein clearance within all cells of eukaryotic organisms. The importance of E3s is highlighted by the number of normal cellular processes they regulate, and the number of diseases associated with their loss of function or inappropriate targeting.

Vorkommen von Antikörpern gegen das bovine Immunschwächevirus bei Rindern in Bayern

2003 ◽  
Vol 31 (05) ◽  
pp. 248-253
Author(s):  
Maren Bartels ◽  
Katrin Hartmann ◽  
L. Scobie ◽  
O. Jarrett ◽  
W. Klee
Keyword(s):  
Western Blot

ZusammenfassungIm Rahmen einer epidemiologischen Untersuchung zur Infektion mit dem bovinen Immunschwächevirus (BIV) bei Rindern in Oberbayern erfolgten zwei Studien, in denen Serum mittels indirektem ELISA auf BIV-Antikörper untersucht wurde. Die ELISA-Ergebnisse der BIV-positiven Tiere der Studie I wurden mittels Western Blot bestätigt. In Studie I wurde Blut von 173 ungezielt ausgewählten Rinderpatienten der II. Medizinischen Tierklinik der Ludwig-Maximilians-Universität München untersucht. Von diesen waren acht Tiere BIV-infiziert. Das entspricht einer Prävalenz von 4,6%. Alle positiven Tiere waren über zwei Monate alt. In Studie II wurden 550 Kühe aus 11 oberbayerischen landwirtschaftlichen Betrieben untersucht. Hiervon waren 11 Tiere BIVAntikör-perpositiv. Dies entspricht einer Prävalenz von 2,0%. Die positiven Tiere stammten aus fünf Betrieben mit Boxenlaufstallhaltung. Kein Tier aus Betrieben mit Anbindehaltung war positiv. In Studie II lag das Durchschnittsalter der Kühe aus den Betrieben ohne BIV-infizierte Tiere signifikant höher als in den Betrieben mit BIV-infizierten Tieren. Die Prävalenz von BIV-Antikörpern war zwar unter den kranken Probanden aus Studie I signifikant höher als bei den klinisch unauffälligen Rindern der Studie II, die pathogene Bedeutung des BIV erscheint jedoch fraglich.

Isolation and Structural Charaderization of a Potent Inhibitor of Coagulation Factor Xa from the Leech Haementeria ghilianii

1989 ◽  
Vol 61 (03) ◽  
pp. 437-441 ◽  
Author(s):  
Cindra Condra ◽  
Elka Nutt ◽  
Christopher J Petroski ◽  
Ellen Simpson ◽  
P A Friedman ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Salivary Gland ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Western Blot ◽  
Potent Inhibitor ◽  
Factor Xa ◽  
Coagulation Factor ◽  
Sds Page ◽  
Bovine Factor

SummaryThe present work reports the discovery and charactenzation of an anticoagulant protein in the salivary gland of the giant bloodsucking leech, H. ghilianii, which is a specific and potent inhibitor of coagulation factor Xa. The inhibitor, purified to homogeneity, displayed subnanomolar inhibition of bovine factor Xa and had a molecular weight of approximately 15,000 as deduced by denaturing SDS-PAGE. The amino acid sequence of the first 43 residues of the H. ghilianii derived inhibitor displayed a striking homology to antistasin, the recently described subnanomolar inhibitor of factor Xa isolated from the Mexican leech, H. officinalis. Antisera prepared to antistasin cross-reacted with the H. ghilianii protein in Western Blot analysis. These data indicate that the giant Amazonian leech, H. ghilianii, and the smaller Mexican leech, H. officinalrs, have similar proteins which disrupt the normal hemostatic clotting mechanisms in their mammalian host’s blood.

Western Blot Analyses of Prekallikrein and its Activation Products in Human Plasma

1991 ◽  
Vol 65 (04) ◽  
pp. 382-388 ◽  
Author(s):  
Dulce Veloso ◽  
Robert W Colman
Keyword(s):  
Complex Formation ◽  
Western Blot ◽  
Human Plasma ◽  
Contact System ◽  
Plasma Activation ◽  
Normal Plasma ◽  
Sds Page ◽  
Activation Products ◽  
Major Antigen ◽  
Formation Of Complexes

SummaryPrekallikrein (PK), a zymogen of the contact system, and its activation products, kallikrein (KAL), KAl-inhibitor complexes and fragments containing KAL epitope(s) have been detected in human plasma by immunoblotting with a monoclonal anti-human plasma PK antibody, MAb 13G1L. Detection of antigen-MAb 13G11 complexes with peroxidase-conjugated anti-IgG showed that the two variants of PK (85- and 88-kDa) are the only major antigen species in normal, non-activated plasma. Upon plasma activation with kaolin, the intensity of the PK bands decreased with formation of complexes of KAL with CL inhibitor (C1 INH) and α2-rrtzcroglobulin (α2M) identical to those formed by the purified proteins. Immunoblots of normal plasma showed good correlation between the PK detected and the amount of plasma assayed. Increasing amounts of KAL incubated with a constant volume of PK-deficient plasma showed increasing amounts of KAL and of KAL-C1 INH and KAL-α2M complexes. Complexes of KALantithrombin III (ATIII) and the ratio of KALα2M/ KAL-CL INH were higher in activated CL INH-deficient plasmas than in activated normal plasmas. Protein resolution by 3-12% gradient SDS-PAGE and epitope detection with [125I]MAb 13G11 showed four KALα2M species and a 45-kDa fragment(s) in both surface-activated normal plasma and complexes formed by purified KAL and α2M. Immunoblots of activated plasma also showed bands at the position of KALCL INH and KALATIII complexes. When α1-antitrypsin Pittsburgh (cα1-AT, Pitts) was added to plasma before activation, KAL-α1-ALPitts was the main complex. The non-activated normal plasma revealed only an overloaded PK band. This is the first report of an antibody that recognizes KAL epitope(s) in KAL-α2M, KALATIII and KALa1-α1Pitts complexes and in the 45-kDa fragment(s). Therefore, MAb 13G11 should be useful for studying the structure of these complexes as well as the mechanism of complex formation. In addition, immunoblotting with MAb 13G11 would allow detection of KAl-inhibitor complexes in patient plasmas as indicators of activation of the contact system.

Differences in the Interactions of Lupus Anticoagulant IgG with Human Prothrombin and Bovine Prothrombin

1995 ◽  
Vol 73 (04) ◽  
pp. 668-674 ◽  
Author(s):  
L Vijaya Mohan Rao ◽  
An D Hoang ◽  
Samuel I Rapaport
Keyword(s):  
Western Blot ◽  
Lupus Anticoagulant ◽  
Protein A ◽  
Phospholipid Complex ◽  
Experimental Conditions ◽  
Bovine Plasma ◽  
Activation System ◽  
Rate Limiting ◽  
Substantial Extent ◽  
Prothrombin Activation

SummaryLupus anticoagulant (LA) IgGs have been reported to inhibit more effectively and consistently the Xa/Va/phospholipid complex-catalyzed activation of human prothrombin than the Xa/Va/phospholipid complex-catalyzed activation of bovine prothrombin. This led us to carry out studies to determine whether the ability to inhibit the activation of prothrombin of LA IgGs, separated from the plasma of 15 patients by protein A affinity chromatography, could be related to the ability of the LA IgGs to bind to prothrombin under various experimental conditions. Of 14 LA IgG preparations tested all prolonged to a variable but substantial extent the dilute Russell’s viper venom time (dRVVT) of human plasma but only minimally prolonged the dRVVT of bovine plasma. In a purified prothrombin activation system with a rate limiting concentration of phospholipid, all 15 LA IgG preparations inhibited the activation of human prothrombin with the majority showing >50% of inhibition. In contrast, only one LA IgG markedly inhibited (>50%) the activation of bovine prothrombin and five others moderately inhibited (25-40%) the activation of bovine prothrombin. Nevertheless, the majority of LA IgG preparations bound to immobilized bovine prothrombin on a Western blot and also to immobilized bovine prothrombin on a microtiter well. In an ELISA in which phosphatidylserine (PS) was immobilized on microtiter wells, bovine prothrombin supported the binding of 10 of 15 LA IgG preparations to PS. However, the extent of binding was lower than that observed with human prothrombin. In experiments with 125I-human prothrombin or 125I-bovine prothrombin in a solution containing Ca2+, the addition of PS/PC vesicles enhanced the binding of both human and bovine prothrombin to some LA IgG preparations. The enhanced binding was particularly evident for bovine prothrombin. Although seemingly related for some preparations, the ability of a LA IgG to bind to bovine prothrombin, either in the presence or absence of PS, and the ability of that LA IgG to inhibit the activation of bovine prothrombin was not consistently related for all preparations.

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