scholarly journals The Vps27/Hrs/STAM (VHS) Domain of the Signal-transducing Adaptor Molecule (STAM) Directs Associated Molecule with the SH3 Domain of STAM (AMSH) Specificity to Longer Ubiquitin Chains and Dictates the Position of Cleavage

2015 ◽  
Vol 291 (4) ◽  
pp. 2033-2042 ◽  
Author(s):  
Nardeen Baiady ◽  
Prasanth Padala ◽  
Bayan Mashahreh ◽  
Einav Cohen-Kfir ◽  
Emily A. Todd ◽  
...  
Keyword(s):  
Structural Model ◽  
Sh3 Domain ◽  
Deubiquitinating Enzyme ◽  
Cleavage Rate ◽  
Ubiquitin Chain ◽  
Interacting Protein ◽  
Chain Cleavage ◽  
Substrate Cleavage ◽  
Vhs Domain

The deubiquitinating enzyme associated molecule with the SH3 domain of STAM (AMSH) is crucial for the removal of ubiquitin molecules during receptor-mediated endocytosis and lysosomal receptor sorting. AMSH interacts with signal transducing adapter molecule (STAM) 1 or 2, which enhances the activity of AMSH through an unknown mechanism. This stimulation is dependent on the ubiquitin-interacting motif of STAM. Here we investigate the specific mechanism of AMSH stimulation by STAM proteins and the role of the STAM Vps27/Hrs/STAM domain. We show that, in the presence of STAM, the length of the ubiquitin chains affects the apparent cleavage rate. Through measurement of the chain cleavage kinetics, we found that, although the kcat of Lys63-linked ubiquitin chain cleavage was comparable for di- and tri-ubiquitin, the Km value was lower for tri-ubiquitin. This increased affinity for longer chains was dependent on the Vps27/Hrs/STAM domain of STAM and required that the substrate ubiquitin chain contain homogenous Lys63-linkages. In addition, STAM directed AMSH cleavage toward the distal isopeptide bond in tri-ubiquitin chains. Finally, we generated a structural model of AMSH-STAM to show how the complex binds Lys63-linked ubiquitin chains and cleaves at the distal end. These data show how a deubiquitinating enzyme-interacting protein dictates the efficiency and specificity of substrate cleavage.

scholarly journals ­­LUBAC deficiency perturbs TLR3 signaling to cause immunodeficiency and autoinflammation

2016 ◽  
Vol 213 (12) ◽  
pp. 2671-2689 ◽  
Author(s):  
Julia Zinngrebe ◽  
Eva Rieser ◽  
Lucia Taraborrelli ◽  
Nieves Peltzer ◽  
Torsten Hartwig ◽  
...  
Keyword(s):  
Cell Death ◽  
Influenza A ◽  
Gene Activation ◽  
Ubiquitin Chain ◽  
Interacting Protein ◽  
Signaling Complex ◽  
Biochemical Level ◽  
Chronic Proliferative Dermatitis ◽  
Tlr3 Signaling

The linear ubiquitin chain assembly complex (LUBAC), consisting of SHANK-associated RH-domain–interacting protein (SHARPIN), heme-oxidized IRP2 ubiquitin ligase-1 (HOIL-1), and HOIL-1–interacting protein (HOIP), is a critical regulator of inflammation and immunity. This is highlighted by the fact that patients with perturbed linear ubiquitination caused by mutations in the Hoip or Hoil-1 genes, resulting in knockouts of these proteins, may simultaneously suffer from immunodeficiency and autoinflammation. TLR3 plays a crucial, albeit controversial, role in viral infection and tissue damage. We identify a pivotal role of LUBAC in TLR3 signaling and discover a functional interaction between LUBAC components and TLR3 as crucial for immunity to influenza A virus infection. On the biochemical level, we identify LUBAC components as interacting with the TLR3-signaling complex (SC), thereby enabling TLR3-mediated gene activation. Absence of LUBAC components increases formation of a previously unrecognized TLR3-induced death-inducing SC, leading to enhanced cell death. Intriguingly, excessive TLR3-mediated cell death, induced by double-stranded RNA present in the skin of SHARPIN-deficient chronic proliferative dermatitis mice (cpdm), is a major contributor to their autoinflammatory skin phenotype, as genetic coablation of Tlr3 substantially ameliorated cpdm dermatitis. Thus, LUBAC components control TLR3-mediated innate immunity, thereby preventing development of immunodeficiency and autoinflammation.

scholarly journals Role of Virally-Encoded Deubiquitinating Enzymes in Regulation of the Virus Life Cycle

2021 ◽  
Vol 22 (9) ◽  
pp. 4438
Author(s):  
Jessica Proulx ◽  
Kathleen Borgmann ◽  
In-Woo Park
Keyword(s):  
Immune Response ◽  
Life Cycle ◽  
Deubiquitinating Enzyme ◽  
Deubiquitinating Enzymes ◽  
Antiviral Immune Response ◽  
Cellular Processes ◽  
Virus Life Cycle ◽  
Infected Cells ◽  
Dependent Processes

The ubiquitin (Ub) proteasome system (UPS) plays a pivotal role in regulation of numerous cellular processes, including innate and adaptive immune responses that are essential for restriction of the virus life cycle in the infected cells. Deubiquitination by the deubiquitinating enzyme, deubiquitinase (DUB), is a reversible molecular process to remove Ub or Ub chains from the target proteins. Deubiquitination is an integral strategy within the UPS in regulating survival and proliferation of the infecting virus and the virus-invaded cells. Many viruses in the infected cells are reported to encode viral DUB, and these vial DUBs actively disrupt cellular Ub-dependent processes to suppress host antiviral immune response, enhancing virus replication and thus proliferation. This review surveys the types of DUBs encoded by different viruses and their molecular processes for how the infecting viruses take advantage of the DUB system to evade the host immune response and expedite their replication.

scholarly journals Role of Thioredoxin-Interacting Protein in Diseases and Its Therapeutic Outlook

2021 ◽  
Vol 22 (5) ◽  
pp. 2754
Author(s):  
Naila Qayyum ◽  
Muhammad Haseeb ◽  
Moon Suk Kim ◽  
Sangdun Choi
Keyword(s):  
Interacting Protein ◽  
Thioredoxin Interacting Protein ◽  
Signaling Complex ◽  
Current Review ◽  
Wide Range ◽  
Range Of Functions ◽  
Species Production ◽  
And Oxidative Stress ◽  
Significant Attention

Thioredoxin-interacting protein (TXNIP), widely known as thioredoxin-binding protein 2 (TBP2), is a major binding mediator in the thioredoxin (TXN) antioxidant system, which involves a reduction-oxidation (redox) signaling complex and is pivotal for the pathophysiology of some diseases. TXNIP increases reactive oxygen species production and oxidative stress and thereby contributes to apoptosis. Recent studies indicate an evolving role of TXNIP in the pathogenesis of complex diseases such as metabolic disorders, neurological disorders, and inflammatory illnesses. In addition, TXNIP has gained significant attention due to its wide range of functions in energy metabolism, insulin sensitivity, improved insulin secretion, and also in the regulation of glucose and tumor suppressor activities in various cancers. This review aims to highlight the roles of TXNIP in the field of diabetology, neurodegenerative diseases, and inflammation. TXNIP is found to be a promising novel therapeutic target in the current review, not only in the aforementioned diseases but also in prolonged microvascular and macrovascular diseases. Therefore, TXNIP inhibitors hold promise for preventing the growing incidence of complications in relevant diseases.

scholarly journals Phosphorylation of Rab11-FIP2 regulates polarity in MDCK cells

2012 ◽  
Vol 23 (12) ◽  
pp. 2302-2318 ◽  
Author(s):  
Lynne A. Lapierre ◽  
Kenya M. Avant ◽  
Cathy M. Caldwell ◽  
Asli Oztan ◽  
Gerard Apodaca ◽  
...  
Keyword(s):  
Tight Junctions ◽  
Mdck Cell ◽  
Mdck Cells ◽  
Adherens Junction ◽  
Cellular Polarity ◽  
Interacting Protein ◽  
P120 Catenin ◽  
Myosin Vb ◽  
Darby Canine Kidney

The Rab11 effector Rab11-family interacting protein 2 (Rab11-FIP2) regulates transcytosis through its interactions with Rab11a and myosin Vb. Previous studies implicated Rab11-FIP2 in the establishment of polarity in Madin–Darby canine kidney (MDCK) cells through phosphorylation of Ser-227 by MARK2. Here we examine the dynamic role of Rab11-FIP2 phosphorylation on MDCK cell polarity. Endogenous Rab11-FIP2 phosphorylated on Ser-227 coalesces on vesicular plaques during the reestablishment of polarity after either monolayer wounding or calcium switch. Whereas expression of the nonphosphorylatable Rab11-FIP2(S227A) elicits a loss in lumen formation in MDCK cell cysts grown in Matrigel, the putative pseudophosphorylated Rab11-FIP2(S227E) mutant induces the formation of cysts with multiple lumens. On permeable filters, Rab11-FIP2(S227E)–expressing cells exhibit alterations in the composition of both the adherens and tight junctions. At the adherens junction, p120 catenin and K-cadherin are retained, whereas the majority of the E-cadherin is lost. Although ZO-1 is retained at the tight junction, occludin is lost and the claudin composition is altered. Of interest, the effects of Rab11-FIP2 on cellular polarity did not involve myosin Vb or Rab11a. These results indicate that Ser-227 phosphorylation of Rab11-FIP2 regulates the composition of both adherens and tight junctions and is intimately involved in the regulation of polarity in epithelial cells.

Spirituality in patients with advanced illness: The role of symptom control, resilience and social network

2016 ◽  
Vol 21 (12) ◽  
pp. 2765-2774 ◽  
Author(s):  
Miguel Fombuena ◽  
Laura Galiana ◽  
Pilar Barreto ◽  
Amparo Oliver ◽  
Antonio Pascual ◽  
...  
Keyword(s):  
Social Support ◽  
Structural Model ◽  
Symptom Control ◽  
Cross Sectional Study ◽  
Physical Symptoms ◽  
Advanced Illness ◽  
Cross Sectional ◽  
Palliative Care Teams ◽  
Symptomatic Control

In this study, we analyzed the relationships among clinical, emotional, social, and spiritual dimensions of patients with advanced illness. It was a cross-sectional study, with a sample of 108 patients in an advanced illness situation attended by palliative care teams. Statistically significant correlations were found between some dimensions of spirituality and poor symptomatic control, resiliency, and social support. In the structural model, three variables predicted spirituality: having physical symptoms as the main source of discomfort, resiliency, and social support. This work highlights the relevance of the relationships among spirituality and other aspects of the patient at the end of life.

Innovation with flow at work: exploring the role of servant leadership in affecting innovative work behavior through flow at work

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Muhammad Mumtaz Khan ◽  
Muhammad Shujaat Mubarik ◽  
Syed Saad Ahmed ◽  
Tahir Islam ◽  
Essa Khan
Keyword(s):  
Servant Leadership ◽  
Structural Model ◽  
Measurement Model ◽  
Work Behavior ◽  
Content Type ◽  
Innovative Work Behavior ◽  
Mediating Role ◽  
Innovative Work ◽  
Flow At Work

PurposeThis study aims to ascertain the role of servant leadership in inducing flow at work. The study, along with confirming the relation between flow at work and innovative work behavior (IWB), intends to explore the mediating role flow at work plays in relating servant leadership to IWB.Design/methodology/approachThe data collection was conducted through an interviewee-administered questionnaire in three waves that were four weeks apart. The data were collected from 267 respondents. To run the measurement model and structural model, Smart-PLS was used, and Statistical Product and Service Solutions (SPSS) was used to summarize the demographic information and conduct hierarchal regression.FindingsServant leadership is related to flow at work. Additionally, flow at work is related to IWB. Finally, flow at work mediates the relationship between servant leadership and IWB.Originality/valueThe study found servant leadership is related to flow at work. Moreover, the study unearthed the relation between flow at work and IWB. Finally, the study unveiled that flow at work acts as a mediator between servant leadership and IWB.

scholarly journals SKIP Downregulation Increases TGF-β1-Induced Matrix Metalloproteinase-9 Production in Transformed Keratinocytes

Scientifica ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Jelena Kocić ◽  
Victor Villar ◽  
Aleksandra Krstić ◽  
Juan F. Santibanez
Keyword(s):  
Matrix Metalloproteinase ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Regulatory Protein ◽  
Mek Inhibitor ◽  
Matrix Metalloproteinase 9 ◽  
Transformed Cells ◽  
Interacting Protein ◽  
Metalloproteinase 9

Transforming growth factor-beta (TGF-β1) is a potent inductor of matrix metalloproteinase-9 (MMP-9) in transformed cells. Recently, Ski-interacting protein (SKIP) has been described as a regulator of TGF-β1 signal transduction, but its role in the induction of cell malignance by TGF-β1 has not been fully elucidated so far. In the present study, we analyzed the role of SKIP on TGF-β1-induced MMP-9 production. Mouse transformed keratinocytes (PDV) were stably transfected with SKIP antisense construct. We observed that SKIP depletion provoked an enhancement in the expression of MMP-9 in response to TGF-β1 treatment. The downregulation of SKIP produced an enhancement in TGF-β1-activated ERK1,2 MAP kinase as well as increased transactivation of downstream Elk1 transcription factor. The increased MMP-9 production in response to TGF-β1 was dependent of MAPK activation as PD98059, an MEK inhibitor, reduced MMP-9 expression in SKIP antisense transfected cells. Thus, we propose SKIP as a regulatory protein in TGF-β1-induced MMP-9 expression acting by controlling ERK1,2 signaling in transformed cells.

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