scholarly journals A Spider Silk-derived Solubility Domain Inhibits Nuclear and Cytosolic Protein Aggregation in Human Cells

2021 ◽  
Author(s):  
Katharina Schellhaus ◽  
Maria Gierisch ◽  
Julia Vornberger ◽  
Jan Johansson ◽  
Nico Dantuma
Keyword(s):  
Protein Aggregation ◽  
Spider Silk ◽  
Subcellular Location ◽  
Human Cells ◽  
Negative Consequences ◽  
Reporter Protein ◽  
Amyloidogenic Proteins ◽  
Human Disorders ◽  
Associated Proteins ◽  
Aggregation Activity

Abstract Due to the inherent toxicity of protein aggregates, the propensity of natural, functional amyloidogenic proteins to aggregate must be tightly controlled to avoid negative consequences on cellular viability. The importance of controlled aggregation in biological processes is illustrated by spidroins, which are functional amyloidogenic proteins that form the basis for spider silk. Premature aggregation of spidroins is prevented by the N-terminal NT domain. Here we explored the potential of the engineered, spidroin-based NT* domain in preventing protein aggregation in the intracellular environment of human cells. We show that the NT* domain increases the soluble pool of a reporter protein carrying a ligand-regulatable aggregation domain. Interestingly, the NT* domain prevents the formation of aggregates independent of its position in the aggregation-prone protein. The ability of the NT* domain to inhibit ligand-regulated aggregation was evident both in the cytosolic and nuclear compartments, which are both highly relevant for human disorders linked to non-physiological protein aggregation. We conclude that the spidroin-derived NT* domain has a generic anti-aggregation activity, independent of position or subcellular location, that is also active in human cells and propose that the NT* domain can potentially be exploited in controlling protein aggregation of disease-associated proteins.

scholarly journals The Annexin A2/S100A10 System in Health and Disease: Emerging Paradigms

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Nadia Hedhli ◽  
Domenick J. Falcone ◽  
Bihui Huang ◽  
Gabriela Cesarman-Maus ◽  
Rosemary Kraemer ◽  
...  
Keyword(s):  
Serotonin Receptor ◽  
Human Cancer ◽  
High Titer ◽  
Critical Role ◽  
Annexin A2 ◽  
Avascular Osteonecrosis ◽  
Kinase Substrate ◽  
New Findings ◽  
Human Disorders ◽  
Associated Proteins

Since its discovery as a src kinase substrate more than three decades ago, appreciation for the physiologic functions of annexin A2 and its associated proteins has increased dramatically. With its binding partner S100A10 (p11), A2 forms a cell surface complex that regulates generation of the primary fibrinolytic protease, plasmin, and is dynamically regulated in settings of hemostasis and thrombosis. In addition, the complex is transcriptionally upregulated in hypoxia and promotes pathologic neoangiogenesis in the tissues such as the retina. Dysregulation of both A2 and p11 has been reported in examples of rodent and human cancer. Intracellularly, A2 plays a critical role in endosomal repair in postarthroplastic osteolysis, and intracellular p11 regulates serotonin receptor activity in psychiatric mood disorders. In human studies, the A2 system contributes to the coagulopathy of acute promyelocytic leukemia, and is a target of high-titer autoantibodies in patients with antiphospholipid syndrome, cerebral thrombosis, and possibly preeclampsia. Polymorphisms in the humanANXA2gene have been associated with stroke and avascular osteonecrosis of bone, two severe complications of sickle cell disease. Together, these new findings suggest that manipulation of the annexin A2/S100A10 system may offer promising new avenues for treatment of a spectrum of human disorders.

The RAV12 Monoclonal Antibody Recognizes the N-Linked Glycotope RAAG12: Expression in Human Normal and Tumor Tissues

2009 ◽  
Vol 133 (9) ◽  
pp. 1403-1412
Author(s):  
Suzanne K. Coberly ◽  
Francine Z. Chen ◽  
Mark P. Armanini ◽  
Yan Chen ◽  
Peter F. Young ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Antigen Expression ◽  
Subcellular Location ◽  
Carbohydrate Antigen ◽  
Cytoplasmic Staining ◽  
Safety Issues ◽  
Normal Tissues ◽  
Tumor Tissues ◽  
Associated Proteins

Abstract Context.—RAAG12 is a primate-restricted N-linked carbohydrate antigen present on multiple membrane-associated proteins. RAAG12 is recognized by the RAV12 monoclonal antibody. RAV12 binds to RAAG12-expressing gastrointestinal adenocarcinomas, modifies growth factor-mediated signaling, induces oncotic cell death in vitro, and has antitumor activity toward gastrointestinal tumor xenografts. Objective.—To determine the expression pattern of RAAG12 in normal and tumor tissue to identify indications for clinical study and potential safety issues. Design.—Immunohistochemistry of 36 normal human tissues and a broad range of tumor tissues to profile RAAG12 expression. Results.—More than 90% of colon, gastric, and pancreatic adenocarcinomas expressed RAAG12, and expression was uniform in most samples. Expression of RAAG12 at lower frequency and/or uniformity was observed in other cancers, including esophageal, ovarian, liver, breast, and prostate carcinomas and adenocarcinomas. Similar RAAG12 expression was observed between primary and metastatic colon adenocarcinomas. No staining was seen on cardiovascular, endocrine, neuromuscular, hematopoietic, or nervous system tissue from non–tumor-bearing individuals. RAAG12 was expressed on mucosal and glandular/ductal epithelium. The gastrointestinal tract mucosa and pancreatic/biliary ducts displayed the most uniform reactivity. RAAG12 exhibited differential subcellular localization in these normal, compared with tumor, tissues. Normal polarized epithelia primarily displayed apical membrane and cytoplasmic staining, whereas tumors exhibited whole membrane staining that increased with decreasing differentiation. Conclusions.—High expression of RAAG12 on tumors of gastrointestinal origin suggests these cancers are appropriate targets for RAV12 therapy. Differential subcellular location of RAAG12 on normal epithelia may limit accessibility of RAV12 to the subset of normal tissues that exhibit antigen expression.

scholarly journals Subversion of the Heme Oxygenase-1 Antiviral Activity by Zika Virus

Viruses ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 2 ◽  
Author(s):  
Chaker El Kalamouni ◽  
Etienne Frumence ◽  
Sandra Bos ◽  
Jonathan Turpin ◽  
Brice Nativel ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Heme Oxygenase ◽  
Zika Virus ◽  
Fluorescent Protein ◽  
Human Cells ◽  
Heme Oxygenase 1 ◽  
Viral Inhibition ◽  
Reporter Protein ◽  
Wide Range ◽  
Rna Replicon

Heme oxygenase-1 (HO-1), a rate-limiting enzyme involved in the degradation of heme, is induced in response to a wide range of stress conditions. HO-1 exerts antiviral activity against a broad range of viruses, including the Hepatitis C virus, the human immunodeficiency virus, and the dengue virus by inhibiting viral growth. It has been reported that HO-1 displays antiviral activity against the Zika virus (ZIKV) but the mechanisms of viral inhibition remain largely unknown. Using a ZIKV RNA replicon with the Green Fluorescent Protein (GFP) as a reporter protein, we were able to show that HO-1 expression resulted in the inhibition of viral RNA replication. Conversely, we observed a decrease in HO-1 expression in cells replicating the ZIKV RNA replicon. The study of human cells infected with ZIKV showed that the HO-1 expression level was significantly lower once viral replication was established, thereby limiting the antiviral effect of HO-1. Our work highlights the capacity of ZIKV to thwart the anti-replicative activity of HO-1 in human cells. Therefore, the modulation of HO-1 as a novel therapeutic strategy against ZIKV infection may display limited effect.

scholarly journals Natural and designed proteins inspired by extremotolerant organisms can form condensates and attenuate apoptosis in human cells

2021 ◽  
Author(s):  
Mike T. Veling ◽  
Dan T. Nguyen ◽  
Nicole N. Thadani ◽  
Michela E. Oster ◽  
Nathan J. Rollins ◽  
...  
Keyword(s):  
Phase Separation ◽  
Intrinsically Disordered Proteins ◽  
Human Cells ◽  
Disordered Proteins ◽  
Cellular Protection ◽  
Intrinsically Disordered ◽  
Apoe Protein ◽  
Condensate Formation ◽  
Associated Proteins ◽  
Induced Apoptosis

ABSTRACTMany organisms can survive extreme conditions and successfully recover to normal life. This extremotolerant behavior has been attributed in part to repetitive, amphipathic, and intrinsically disordered proteins that are upregulated in the protected state. Here, we assemble a library of approximately 300 naturally-occurring and designed extremotolerance-associated proteins to assess their ability to protect human cells from chemically-induced apoptosis. We show that proteins from tardigrades, nematodes, and the Chinese giant salamander are apoptosis protective. Notably, we identify a region of the human ApoE protein with similarity to extremotolerance-associated proteins that also protects against apoptosis. This region mirrors the phase separation behavior seen with such proteins, like the tardigrade protein CAHS2. Moreover, we identify a synthetic protein, DHR81, that shares this combination of elevated phase separation propensity and apoptosis protection. Finally, we demonstrate that driving protective proteins into the condensate state increases apoptosis protection, and highlight the ability for DHR81 condensates to sequester caspase-7. Taken together, this work draws a link between extremotolerance-associated proteins, condensate formation, and human cellular protection.

scholarly journals Catechol-Containing Compounds are a Broad Class of Protein Aggregation Inhibitors: Redox State is a Key Determinant of the Inhibitory Activities

2020 ◽  
Author(s):  
Paul Velander ◽  
Ling Wu ◽  
Sherry B. Hildreth ◽  
Nancy J. Vogelaar ◽  
Biswarup Mukhopadhyay ◽  
...  
Keyword(s):  
Protein Aggregation ◽  
Small Molecule ◽  
Rational Design ◽  
Redox State ◽  
Broad Class ◽  
Intrinsically Disordered ◽  
Amyloidogenic Proteins ◽  
Key Factor ◽  
Inhibitory Activities ◽  
Screening Platform

Abstract Background: A range of neurodegenerative and related aging diseases, such as Alzheimer’s disease, Parkinson’s disease, and type 2 diabetes, are linked to toxic protein aggregation. Yet the mechanisms of protein aggregation inhibition by small molecule inhibitors remain poorly understood, in part because most protein targets of aggregation assembly are partially unfolded or intrinsically disordered, which hinders detailed structural characterization of protein-inhibitor complexes and structural-based mechanistic elucidation. Methods: Herein we employed a small molecule screening approach to identify inhibitors against three prototype amyloidogenic proteins in neurodegeneration and related proteinopathies: amylin, Ab and tau. We further systematically investigated selected class of inhibitors under aerobic and anaerobic conditions to uncover a key determinant of the inhibitory activities.Results: One remarkable class of inhibitors identified from all three parallel screenings against different amyloidogenic proteins was catechol-containing compounds and redox-related quinones/anthraquinones. Further mechanistic studies determined that the redox state of the broad class of catechol-containing compounds is a key determinant of the amyloid inhibitor activities. Conclusion: Our small molecule library screening platform was able to identify a broad class of amyloid inhibitors. Redox was found to be a key factor not only regulating the inhibitory activities but also involving the mechanism of inhibition. The molecular insights we gained not only explain why a large number of catechol-containing natural compounds, often enriched in healthy diet, have anti-neurodegeneration and anti-aging activities, but also could guide the rational design of therapeutic or nutraceutical strategies to target a broad range of neurodegenerative and related aging diseases.

scholarly journals The central domain of yeast transcription factor Rpn4 facilitates degradation of reporter protein in human cells

FEBS Letters ◽  
2014 ◽  
Vol 588 (20) ◽  
pp. 3713-3719 ◽  
Author(s):  
A.V. Morozov ◽  
D.S. Spasskaya ◽  
D.S. Karpov ◽  
V.L. Karpov
Keyword(s):  
Transcription Factor ◽  
Human Cells ◽  
Reporter Protein ◽  
Central Domain

scholarly journals Incredibly close—A newly identified peroxisome–ER contact site in humans

2017 ◽  
Vol 216 (2) ◽  
pp. 287-289 ◽  
Author(s):  
Maya Schuldiner ◽  
Einat Zalckvar
Keyword(s):  
Endoplasmic Reticulum ◽  
Membrane Protein ◽  
Binding Protein ◽  
Human Cells ◽  
Metabolic Processes ◽  
Contact Site ◽  
Cell Biol ◽  
Associated Proteins

Peroxisomes are tiny organelles that control important and diverse metabolic processes via their interplay with other organelles, including the endoplasmic reticulum (ER). In this issue, Costello et al. (2017. J. Cell Biol. https://doi.org/10.1083/jcb.201607055) and Hua et al. (2017. J. Cell Biol. https://doi.org/10.1083/jcb.201608128) identify a peroxisome–ER contact site in human cells held together by a tethering complex of VAPA/B (vesicle-associated membrane protein–associated proteins A/B) and ACBD5 (acyl Co-A binding protein 5).

scholarly journals Exogenous amyloidogenic proteins function as seeds in amyloid β-protein aggregation

2014 ◽  
Vol 1842 (4) ◽  
pp. 646-653 ◽  
Author(s):  
Kenjiro Ono ◽  
Ryoichi Takahashi ◽  
Tokuhei Ikeda ◽  
Mineyuki Mizuguchi ◽  
Tsuyoshi Hamaguchi ◽  
...  
Keyword(s):  
Protein Aggregation ◽  
Amyloid Β ◽  
Amyloid Β Protein ◽  
Amyloidogenic Proteins ◽  
Β Protein

scholarly journals Desmin-related cardiomyopathy: an unfolding story

2011 ◽  
Vol 301 (4) ◽  
pp. H1220-H1228 ◽  
Author(s):  
Patrick M. McLendon ◽  
Jeffrey Robbins
Keyword(s):  
Protein Aggregation ◽  
Striated Muscle ◽  
Intermediate Filament Protein ◽  
Cytoskeletal Organization ◽  
Sarcoplasmic Protein ◽  
Amyloid Oligomers ◽  
Abnormal Metabolism ◽  
Associated Proteins ◽  
Cellular Phenotypes ◽  
Filament Protein

The intermediate filament protein desmin is an integral component of the cardiomyocyte and serves to maintain the overall structure and cytoskeletal organization within striated muscle cells. Desmin-related myopathy can be caused by mutations in desmin or associated proteins, which leads to intracellular accumulation of misfolded protein and production of soluble pre-amyloid oligomers, which leads to weakened skeletal and cardiac muscle. In this review, we examine the cellular phenotypes in relevant animal models of desmin-related cardiomyopathy. These models display characteristic sarcoplasmic protein aggregates. Aberrant protein aggregation leads to mitochondrial dysfunction, abnormal metabolism, and altered cardiomyocyte structure. These deficits to cardiomyocyte function may stem from impaired cellular proteolytic mechanisms. The data obtained from these models allow a more complete picture of the pathology in desmin-related cardiomyopathy to be described. Moreover, these studies highlight the importance of desmin in maintaining cardiomyocyte structure and illustrate how disrupting this network can be deleterious to the heart. We emphasize the similarities observed between desmin-related cardiomyopathy and other protein conformational disorders and speculate that therapies to treat this disease may be broadly applicable to diverse protein aggregation-based disorders.

scholarly journals Therapeutic genetic variation revealed in diverse Hsp104 homologs

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Zachary M March ◽  
Katelyn Sweeney ◽  
Hanna Kim ◽  
Xiaohui Yan ◽  
Laura M Castellano ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Protein Aggregation ◽  
Neurodegenerative Disease ◽  
Human Cells ◽  
C Elegans ◽  
Dopaminergic Neurodegeneration ◽  
Aaa Protein ◽  
Selective Activity

The AAA+ protein disaggregase, Hsp104, increases fitness under stress by reversing stress-induced protein aggregation. Natural Hsp104 variants might exist with enhanced, selective activity against neurodegenerative disease substrates. However, natural Hsp104 variation remains largely unexplored. Here, we screened a cross-kingdom collection of Hsp104 homologs in yeast proteotoxicity models. Prokaryotic ClpG reduced TDP-43, FUS, and α-synuclein toxicity, whereas prokaryotic ClpB and hyperactive variants were ineffective. We uncovered therapeutic genetic variation among eukaryotic Hsp104 homologs that specifically antagonized TDP-43 condensation and toxicity in yeast and TDP-43 aggregation in human cells. We also uncovered distinct eukaryotic Hsp104 homologs that selectively antagonized α-synuclein condensation and toxicity in yeast and dopaminergic neurodegeneration in C. elegans. Surprisingly, this therapeutic variation did not manifest as enhanced disaggregase activity, but rather as increased passive inhibition of aggregation of specific substrates. By exploring natural tuning of this passive Hsp104 activity, we elucidated enhanced, substrate-specific agents that counter proteotoxicity underlying neurodegeneration.

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