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Recent Publications

A synthetic intrabody-based selective and generic inhibitor of GPCR endocytosis.

A synthetic intrabody-based selective and generic inhibitor of GPCR endocytosis.

Nat Nanotechnol. 2017 Oct 02;:

Authors: Ghosh E, Srivastava A, Baidya M, Kumari P, Dwivedi H, Nidhi K, Ranjan R, Dogra S, Koide A, Yadav PN, Sidhu SS, Koide S, Shukla AK

Abstract
Beta-arrestins (βarrs) critically mediate desensitization, endocytosis and signalling of G protein-coupled receptors (GPCRs), and they scaffold a large number of interaction partners. However, allosteric modulation of their scaffolding abilities and direct targeting of their interaction interfaces to modulate GPCR functions selectively have not been fully explored yet. Here we identified a series of synthetic antibody fragments (Fabs) against different conformations of βarrs from phage display libraries. Several of these Fabs allosterically and selectively modulated the interaction of βarrs with clathrin and ERK MAP kinase. Interestingly, one of these Fabs selectively disrupted βarr-clathrin interaction, and when expressed as an intrabody, it robustly inhibited agonist-induced endocytosis of a broad set of GPCRs without affecting ERK MAP kinase activation. Our data therefore demonstrate the feasibility of selectively targeting βarr interactions using intrabodies and provide a novel framework for fine-tuning GPCR functions with potential therapeutic implications.

PMID: 28967893 [PubMed - as supplied by publisher]



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Pathway-based discovery of genetic interactions in breast cancer.

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Pathway-based discovery of genetic interactions in breast cancer.

PLoS Genet. 2017 Sep;13(9):e1006973

Authors: Wang W, Xu ZZ, Costanzo M, Boone C, Lange CA, Myers CL

Abstract
Breast cancer is the second largest cause of cancer death among U.S. women and the leading cause of cancer death among women worldwide. Genome-wide association studies (GWAS) have identified several genetic variants associated with susceptibility to breast cancer, but these still explain less than half of the estimated genetic contribution to the disease. Combinations of variants (i.e. genetic interactions) may play an important role in breast cancer susceptibility. However, due to a lack of statistical power, the current tests for genetic interactions from GWAS data mainly leverage prior knowledge to focus on small sets of genes or SNPs that are known to have an association with breast cancer. Thus, many genetic interactions, particularly among novel variants, remain understudied. Reverse-genetic interaction screens in model organisms have shown that genetic interactions frequently cluster into highly structured motifs, where members of the same pathway share similar patterns of genetic interactions. Based on this key observation, we recently developed a method called BridGE to search for such structured motifs in genetic networks derived from GWAS studies and identify pathway-level genetic interactions in human populations. We applied BridGE to six independent breast cancer cohorts and identified significant pathway-level interactions in five cohorts. Joint analysis across all five cohorts revealed a high confidence consensus set of genetic interactions with support in multiple cohorts. The discovered interactions implicated the glutathione conjugation, vitamin D receptor, purine metabolism, mitotic prometaphase, and steroid hormone biosynthesis pathways as major modifiers of breast cancer risk. Notably, while many of the pathways identified by BridGE show clear relevance to breast cancer, variants in these pathways had not been previously discovered by traditional single variant association tests, or single pathway enrichment analysis that does not consider SNP-SNP interactions.

PMID: 28957314 [PubMed - indexed for MEDLINE]



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Nanomedicine 2.0.

Nanomedicine 2.0.

Acc Chem Res. 2017 Mar 21;50(3):627-632

Authors: Chan WCW

Abstract
Nanotechnology can profoundly change the way we diagnose and treat diseases, but the ability to control how engineered nanoparticles behave within the body remains largely elusive. This Commentary describes the progress and limitations of nanomedicine and the research and experimental philosophies that should be considered in our quest to advance nanotechnology to the clinic.

PMID: 28945418 [PubMed - in process]



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A novel immunotherapy targeting MMP-14 limits hypoxia, immune suppression and metastasis in triple-negative breast cancer models.

A novel immunotherapy targeting MMP-14 limits hypoxia, immune suppression and metastasis in triple-negative breast cancer models.

Oncotarget. 2017 Aug 29;8(35):58372-58385

Authors: Ling B, Watt K, Banerjee S, Newsted D, Truesdell P, Adams J, Sidhu SS, Craig AWB

Abstract
Matrix metalloproteinase-14 (MMP-14) is a clinically relevant target in metastatic cancers due to its role in tumor progression and metastasis. Since active MMP-14 is localized on the cell surface, it is amenable to antibody-mediated blockade in cancer, and here we describe our efforts to develop novel inhibitory anti-MMP-14 antibodies. A phage-displayed synthetic humanized Fab library was screened against the extracellular domain of MMP-14 and a panel of MMP14-specific Fabs were identified. A lead antibody that inhibits the catalytic domain of MMP-14 (Fab 3369) was identified and treatment of MDA-MB-231 breast cancer cells with Fab 3369 led to significant loss of extracellular matrix degradation and cell invasion abilities. In mammary orthotopic tumor xenograft assays, MMP-14 blockade by IgG 3369 limited tumor growth and metastasis. Analysis of tumor tissue sections revealed that MMP-14 blockade limited tumor neoangiogenesis and hypoxia. Similar effects of MMP-14 blockade in syngeneic 4T1 mammary tumors were observed, along with increased detection of cytotoxic immune cell markers. In conclusion, we show that immunotherapies targeting MMP-14 can limit immune suppression, tumor progression, and metastasis in triple-negative breast cancer.

PMID: 28938563 [PubMed - in process]



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Mass spectrometry methods to study protein-metabolite interactions.

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Mass spectrometry methods to study protein-metabolite interactions.

Expert Opin Drug Discov. 2017 Sep 21;:1-10

Authors: Guo H, Peng H, Emili A

Abstract
INTRODUCTION: To ​​​​understand and manipulate biochemical processes and signaling pathways, the knowledge of endogenous protein-metabolite interactions would be extremely helpful. Recent developments in precision mass spectrometry, high-throughput proteomics and sensitive metabolomic profiling are beginning to converge on a possible solution, heralding a new era of global metabolome-proteome 'interactome' studies that promise to change biomedical research and drug discovery. Areas covered: Here, we review innovative mass spectrometry-based methods and recent pioneering studies aimed at elucidating the physical associations of small molecule ligands with cellular proteins. The technologies covered belong to two main categories: tag-based and tag-free methods. We emphasize the latter in this review, and outline promising experimental workflows and key data analysis considerations involved. Expert opinion: Recent ground-breaking advances in chemical-proteomics technology and allied computational methods now make the global detection of protein-ligand engagement an increasingly attractive research problem. Despite ongoing challenges, rapid progress in the field is expected these coming next few years, leading to a refreshed systems biology research paradigm and much needed new opportunities for improving sparse drug discovery pipelines.

PMID: 28933205 [PubMed - as supplied by publisher]



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NDFIP allows NEDD4/NEDD4L-induced AQP2 ubiquitination and degradation.

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NDFIP allows NEDD4/NEDD4L-induced AQP2 ubiquitination and degradation.

PLoS One. 2017;12(9):e0183774

Authors: Trimpert C, Wesche D, de Groot T, Pimentel Rodriguez MM, Wong V, van den Berg DTM, Cheval L, Ariza CA, Doucet A, Stagljar I, Deen PMT

Abstract
Regulation of our water homeostasis is fine-tuned by dynamic translocation of Aquaporin-2 (AQP2)-bearing vesicles to and from the plasma membrane of renal principal cells. Whereas binding of vasopressin to its type-2 receptor initiates a cAMP-protein kinase A cascade and AQP2 translocation to the apical membrane, this is counteracted by protein kinase C-activating hormones, resulting in ubiquitination-dependent internalization of AQP2. The proteins targeting AQP2 for ubiquitin-mediated degradation are unknown. In collecting duct mpkCCD cells, siRNA knockdown of NEDD4 and NEDD4L E3 ligases yielded increased AQP2 abundance, but they did not bind AQP2. Membrane Yeast Two-Hybrid assays using full-length AQP2 as bait, identified NEDD4 family interacting protein 2 (NDFIP2) to bind AQP2. NDFIP2 and its homologue NDFIP1 have PY motifs by which they bind NEDD4 family members and bring them close to target proteins. In HEK293 cells, NDFIP1 and NDFIP2 bound AQP2 and were essential for NEDD4/NEDD4L-mediated ubiquitination and degradation of AQP2, an effect not observed with PY-lacking NDFIP1/2 proteins. In mpkCCD cells, downregulation of NDFIP1, NEDD4 and NEDD4L, but not NDFIP2, increased AQP2 abundance. In mouse kidney, Ndfip1 and Ndfip2 mRNA distribution was similar and high in proximal tubules and collecting ducts, which was also found for NDFIP1 proteins. Our results reveal that NEDD4/NEDD4L mediate ubiquitination and degradation of AQP2, but that NDFIP proteins are needed to connect NEDD4/NEDD4L to AQP2. As NDFIP1/2 bind many NEDD4 family E3 ligases, which are implicated in several cellular processes, NDFIP1/2 may be the missing link for AQP2 ubiquitination and degradation from different subcellular locations.

PMID: 28931009 [PubMed - indexed for MEDLINE]



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Protein complexes, big data, machine learning and integrative proteomics: lessons learned over a decade of systematic analysis of protein interaction networks.

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Protein complexes, big data, machine learning and integrative proteomics: lessons learned over a decade of systematic analysis of protein interaction networks.

Expert Rev Proteomics. 2017 Sep 18;:1-11

Authors: Havugimana PC, Hu P, Emili A

Abstract
OVERVIEW: Elucidation of the networks of physical (functional) interactions present in cells and tissues is fundamental for understanding the molecular organization of biological systems, the mechanistic basis of essential and disease-related processes, and for functional annotation of previously uncharacterized proteins (via guilt-by-association or -correlation). After a decade in the field, we felt it timely to document our own experiences in the systematic analysis of protein interaction networks. Areas covered: Researchers worldwide have contributed innovative experimental and computational approaches that have driven the rapidly evolving field of 'functional proteomics'. These include mass spectrometry-based methods to characterize macromolecular complexes on a global-scale and sophisticated data analysis tools - most notably machine learning - that allow for the generation of high-quality protein association maps. Expert commentary: Here, we recount some key lessons learned, with an emphasis on successful workflows, and challenges, arising from our own and other groups' ongoing efforts to generate, interpret and report proteome-scale interaction networks in increasingly diverse biological contexts.

PMID: 28918672 [PubMed - as supplied by publisher]



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P-body proteins regulate transcriptional rewiring to promote DNA replication stress resistance.

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P-body proteins regulate transcriptional rewiring to promote DNA replication stress resistance.

Nat Commun. 2017 Sep 15;8(1):558

Authors: Loll-Krippleber R, Brown GW

Abstract
mRNA-processing (P-) bodies are cytoplasmic granules that form in eukaryotic cells in response to numerous stresses to serve as sites of degradation and storage of mRNAs. Functional P-bodies are critical for the DNA replication stress response in yeast, yet the repertoire of P-body targets and the mechanisms by which P-bodies promote replication stress resistance are unknown. In this study we identify the complete complement of mRNA targets of P-bodies during replication stress induced by hydroxyurea treatment. The key P-body protein Lsm1 controls the abundance of HHT1, ACF4, ARL3, TMA16, RRS1 and YOX1 mRNAs to prevent their toxic accumulation during replication stress. Accumulation of YOX1 mRNA causes aberrant downregulation of a network of genes critical for DNA replication stress resistance and leads to toxic acetaldehyde accumulation. Our data reveal the scope and the targets of regulation by P-body proteins during the DNA replication stress response.P-bodies form in response to stress and act as sites of mRNA storage and degradation. Here the authors identify the mRNA targets of P-bodies during DNA replication stress, and show that P-body proteins act to prevent toxic accumulation of these target transcripts.

PMID: 28916784 [PubMed - in process]



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Features of the Chaperone Cellular Network Revealed through Systematic Interaction Mapping.

Features of the Chaperone Cellular Network Revealed through Systematic Interaction Mapping.

Cell Rep. 2017 Sep 12;20(11):2735-2748

Authors: Rizzolo K, Huen J, Kumar A, Phanse S, Vlasblom J, Kakihara Y, Zeineddine HA, Minic Z, Snider J, Wang W, Pons C, Seraphim TV, Boczek EE, Alberti S, Costanzo M, Myers CL, Stagljar I, Boone C, Babu M, Houry WA

Abstract
A comprehensive view of molecular chaperone function in the cell was obtained through a systematic global integrative network approach based on physical (protein-protein) and genetic (gene-gene or epistatic) interaction mapping. This allowed us to decipher interactions involving all core chaperones (67) and cochaperones (15) of Saccharomyces cerevisiae. Our analysis revealed the presence of a large chaperone functional supercomplex, which we named the naturally joined (NAJ) chaperone complex, encompassing Hsp40, Hsp70, Hsp90, AAA+, CCT, and small Hsps. We further found that many chaperones interact with proteins that form foci or condensates under stress conditions. Using an in vitro reconstitution approach, we demonstrate condensate formation for the highly conserved AAA+ ATPases Rvb1 and Rvb2, which are part of the R2TP complex that interacts with Hsp90. This expanded view of the chaperone network in the cell clearly demonstrates the distinction between chaperones having broad versus narrow substrate specificities in protein homeostasis.

PMID: 28903051 [PubMed - in process]



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State of diagnosing infectious pathogens using colloidal nanomaterials.

State of diagnosing infectious pathogens using colloidal nanomaterials.

Biomaterials. 2017 Aug 17;146:97-114

Authors: Kim J, Mohamed MAA, Zagorovsky K, Chan WCW

Abstract
Infectious diseases are a major global threat that accounts for one of the leading causes of global mortality and morbidity. Prompt diagnosis is a crucial first step in the management of infectious threats, which aims to quarantine infected patients to avoid contacts with healthy individuals and deliver effective treatments prior to further spread of diseases. This review article discusses current advances of diagnostic systems using colloidal nanomaterials (e.g., gold nanoparticles, quantum dots, magnetic nanoparticles) for identifying and differentiating infectious pathogens. The challenges involved in the clinical translation of these emerging nanotechnology based diagnostic devices will also be discussed.

PMID: 28898761 [PubMed - as supplied by publisher]



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