Other search tools

About this data

The publication data currently available has been vetted by Vanderbilt faculty, staff, administrators and trainees. The data itself is retrieved directly from NCBI's PubMed and is automatically updated on a weekly basis to ensure accuracy and completeness.

If you have any questions or comments, please contact us.

Results: 1 to 10 of 63

Publication Record

Connections

A recommended and verified procedure for in situ tryptic digestion of formalin-fixed paraffin-embedded tissues for analysis by matrix-assisted laser desorption/ionization imaging mass spectrometry.
Judd AM, Gutierrez DB, Moore JL, Patterson NH, Yang J, Romer CE, Norris JL, Caprioli RM
(2019) J Mass Spectrom 54: 716-727
MeSH Terms: Formaldehyde, Humans, Paraffin Embedding, Proteins, Proteolysis, Specimen Handling, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, Tissue Array Analysis, Tissue Fixation, Trypsin
Show Abstract · Added October 15, 2019
Matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS) is a molecular imaging technology uniquely capable of untargeted measurement of proteins, lipids, and metabolites while retaining spatial information about their location in situ. This powerful combination of capabilities has the potential to bring a wealth of knowledge to the field of molecular histology. Translation of this innovative research tool into clinical laboratories requires the development of reliable sample preparation protocols for the analysis of proteins from formalin-fixed paraffin-embedded (FFPE) tissues, the standard preservation process in clinical pathology. Although ideal for stained tissue analysis by microscopy, the FFPE process cross-links, disrupts, or can remove proteins from the tissue, making analysis of the protein content challenging. To date, reported approaches differ widely in process and efficacy. This tutorial presents a strategy derived from systematic testing and optimization of key parameters, for reproducible in situ tryptic digestion of proteins in FFPE tissue and subsequent MALDI IMS analysis. The approach describes a generalized method for FFPE tissues originating from virtually any source.
© 2019 John Wiley & Sons, Ltd.
0 Communities
1 Members
0 Resources
MeSH Terms
Intracellular Degradation of Helicobacter pylori VacA Toxin as a Determinant of Gastric Epithelial Cell Viability.
Foegeding NJ, Raghunathan K, Campbell AM, Kim SW, Lau KS, Kenworthy AK, Cover TL, Ohi MD
(2019) Infect Immun 87:
MeSH Terms: Autophagy, Bacterial Proteins, Cell Line, Cell Survival, Epithelial Cells, Gastric Mucosa, Helicobacter Infections, Helicobacter pylori, Humans, Hydrogen-Ion Concentration, Muramidase, Protein Stability, Protein Transport, Proteolysis
Show Abstract · Added February 7, 2019
VacA is a secreted pore-forming toxin that induces cell vacuolation and contributes to the pathogenesis of gastric cancer and peptic ulcer disease. We observed that purified VacA has relatively little effect on the viability of AGS gastric epithelial cells, but the presence of exogenous weak bases such as ammonium chloride (NHCl) enhances the susceptibility of these cells to VacA-induced vacuolation and cell death. Therefore, we tested the hypothesis that NHCl augments VacA toxicity by altering the intracellular trafficking of VacA or inhibiting intracellular VacA degradation. We observed VacA colocalization with LAMP1- and LC3-positive vesicles in both the presence and absence of NHCl, indicating that NHCl does not alter VacA trafficking to lysosomes or autophagosomes. Conversely, we found that supplemental NHCl significantly increases the intracellular stability of VacA. By conducting experiments using chemical inhibitors, stable ATG5 knockdown cell lines, and ATG16L1 knockout cells (generated using CRISPR/Cas9), we show that VacA degradation is independent of autophagy and proteasome activity but dependent on lysosomal acidification. We conclude that weak bases like ammonia, potentially generated during infection by urease and other enzymes, enhance VacA toxicity by inhibiting toxin degradation.
Copyright © 2019 American Society for Microbiology.
0 Communities
1 Members
0 Resources
14 MeSH Terms
Imaging mass spectrometry reveals direct albumin fragmentation within the diabetic kidney.
Grove KJ, Lareau NM, Voziyan PA, Zeng F, Harris RC, Hudson BG, Caprioli RM
(2018) Kidney Int 94: 292-302
MeSH Terms: Albumins, Albuminuria, Animals, Cathepsin D, Diabetic Nephropathies, Disease Models, Animal, Frozen Sections, Humans, Kidney Glomerulus, Kidney Tubules, Mice, Mice, Inbred C57BL, Molecular Imaging, Nitric Oxide Synthase Type III, Proteolysis, Renal Elimination, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
Show Abstract · Added May 29, 2018
Albumin degradation in the renal tubules is impaired in diabetic nephropathy such that levels of the resulting albumin fragments increase with the degree of renal injury. However, the mechanism of albumin degradation is unknown. In particular, fragmentation of the endogenous native albumin has not been demonstrated in the kidney and the enzymes that may contribute to fragmentation have not been identified. To explore this we utilized matrix-assisted laser desorption/ionization imaging mass spectrometry for molecular profiling of specific renal regions without disturbing distinct tissue morphology. Changes in protein expression were measured in kidney sections of eNOSdb/db mice, a model of diabetic nephropathy, by high spatial resolution imaging allowing molecular localizations at the level of single glomeruli and tubules. Significant increases were found in the relative abundances of several albumin fragments in the kidney of the mice with diabetic nephropathy compared with control nondiabetic mice. The relative abundance of fragments detected correlated positively with the degree of nephropathy. Furthermore, specific albumin fragments accumulating in the lumen of diabetic renal tubules were identified and predicted the enzymatic action of cathepsin D based on cleavage specificity and in vitro digestions. Importantly, this was demonstrated directly in the renal tissue with the endogenous nonlabeled murine albumin. Thus, our results provide molecular insights into the mechanism of albumin degradation in diabetic nephropathy.
Copyright © 2018 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.
1 Communities
0 Members
0 Resources
17 MeSH Terms
Mechanisms of KCNQ1 channel dysfunction in long QT syndrome involving voltage sensor domain mutations.
Huang H, Kuenze G, Smith JA, Taylor KC, Duran AM, Hadziselimovic A, Meiler J, Vanoye CG, George AL, Sanders CR
(2018) Sci Adv 4: eaar2631
MeSH Terms: Cell Membrane, HEK293 Cells, Humans, KCNQ1 Potassium Channel, Leupeptins, Long QT Syndrome, Loss of Function Mutation, Magnetic Resonance Spectroscopy, Mutant Proteins, Mutation, Proteasome Endopeptidase Complex, Proteasome Inhibitors, Protein Domains, Protein Folding, Protein Structure, Secondary, Proteolysis
Show Abstract · Added March 14, 2018
Mutations that induce loss of function (LOF) or dysfunction of the human KCNQ1 channel are responsible for susceptibility to a life-threatening heart rhythm disorder, the congenital long QT syndrome (LQTS). Hundreds of mutations have been identified, but the molecular mechanisms responsible for impaired function are poorly understood. We investigated the impact of 51 KCNQ1 variants with mutations located within the voltage sensor domain (VSD), with an emphasis on elucidating effects on cell surface expression, protein folding, and structure. For each variant, the efficiency of trafficking to the plasma membrane, the impact of proteasome inhibition, and protein stability were assayed. The results of these experiments combined with channel functional data provided the basis for classifying each mutation into one of six mechanistic categories, highlighting heterogeneity in the mechanisms resulting in channel dysfunction or LOF. More than half of the KCNQ1 LOF mutations examined were seen to destabilize the structure of the VSD, generally accompanied by mistrafficking and degradation by the proteasome, an observation that underscores the growing appreciation that mutation-induced destabilization of membrane proteins may be a common human disease mechanism. Finally, we observed that five of the folding-defective LQTS mutant sites are located in the VSD S0 helix, where they interact with a number of other LOF mutation sites in other segments of the VSD. These observations reveal a critical role for the S0 helix as a central scaffold to help organize and stabilize the KCNQ1 VSD and, most likely, the corresponding domain of many other ion channels.
0 Communities
3 Members
0 Resources
16 MeSH Terms
Alternative splicing of ALCAM enables tunable regulation of cell-cell adhesion through differential proteolysis.
Hebron KE, Li EY, Arnold Egloff SA, von Lersner AK, Taylor C, Houkes J, Flaherty DK, Eskaros A, Stricker TP, Zijlstra A
(2018) Sci Rep 8: 3208
MeSH Terms: Activated-Leukocyte Cell Adhesion Molecule, Alternative Splicing, Animals, Cell Adhesion, Cell Line, Tumor, Chick Embryo, Chorioallantoic Membrane, Disease Progression, Humans, Matrix Metalloproteinase 14, Neoplasm Metastasis, Proteolysis, Urinary Bladder Neoplasms
Show Abstract · Added March 22, 2018
While many adhesion receptors are known to influence tumor progression, the mechanisms by which they dynamically regulate cell-cell adhesion remain elusive. We previously identified Activated Leukocyte Cell Adhesion Molecule (ALCAM) as a clinically relevant driver of metastasis and hypothesized that a tunable mechanism of ectodomain shedding regulates its contribution to dissemination. To test this hypothesis, we examined an under-explored ALCAM splice variant (ALCAM-Iso2) and demonstrated that loss of the membrane-proximal region of ALCAM (exon 13) increased metastasis four-fold. Mechanistic studies identified a novel MMP14-dependent membrane distal cleavage site in ALCAM-Iso2, which mediated a ten-fold increase in shedding, thereby decreasing cellular cohesion. Importantly, the loss of cohesion is not limited to the cell capable of shedding because the released extracellular domain diminished cohesion of non-shedding cells through disruption of ALCAM-ALCAM interactions. ALCAM-Iso2-dominated expression in bladder cancer tissue, compared to normal bladder, further emphasizes that ALCAM alternative splicing may contribute to clinical disease progression. The requirement for both the loss of exon 13 and the gain of metalloprotease activity suggests that ALCAM shedding and concomitant regulation of tumor cell adhesion is a locally tunable process.
0 Communities
1 Members
0 Resources
13 MeSH Terms
Oxidative stress, caspase-3 activation and cleavage of ROCK-1 play an essential role in MeHg-induced cell death in primary astroglial cells.
Dos Santos AA, López-Granero C, Farina M, Rocha JBT, Bowman AB, Aschner M
(2018) Food Chem Toxicol 113: 328-336
MeSH Terms: Animals, Astrocytes, Caspase 3, Caspase 9, Cell Death, Cells, Cultured, Enzyme Activation, Lim Kinases, Methylmercury Compounds, Mice, Inbred C57BL, Myosin-Light-Chain Phosphatase, Oxidative Stress, Phosphorylation, Proteolysis, rho-Associated Kinases
Show Abstract · Added April 11, 2018
Methylmercury is a toxic environmental contaminant that elicits significant toxicity in humans. The central nervous system is the primary target of toxicity, and is particularly vulnerable during development. Rho-associated protein kinase 1 (ROCK-1) is a major downstream effector of the small GTPase RhoA and a direct substrate of caspase-3. The activation of ROCK-1 is necessary for membrane blebbing during apoptosis. In this work, we examined whether MeHg could affect the RhoA/ROCK-1 signaling pathway in primary cultures of mouse astrocytes. Exposure of cells with 10 μM MeHg decreased cellular viability after 24 h of incubation. This reduction in viability was preceded by a significant increase in intracellular and mitochondrial reactive oxygen species levels, as well as a reduced NAD/NADH ratio. MeHg also induced an increase in mitochondrial-dependent caspase-9 and caspase-3, while the levels of RhoA protein expression were reduced or unchanged. We further found that MeHg induced ROCK-1 cleavage/activation and promoted LIMK1 and MYPT1 phosphorylation, both of which are the best characterized ROCK-1 downstream targets. Inhibiting ROCK-1 and caspases activation attenuated the MeHg-induced cell death. Collectively, these findings are the first to show that astrocytes exposed to MeHg showed increased cleavage/activation of ROCK-1, which was independent of the small GTPase RhoA.
Copyright © 2018. Published by Elsevier Ltd.
0 Communities
1 Members
0 Resources
15 MeSH Terms
Identifying the substrate proteins of U-box E3s E4B and CHIP by orthogonal ubiquitin transfer.
Bhuripanyo K, Wang Y, Liu X, Zhou L, Liu R, Duong D, Zhao B, Bi Y, Zhou H, Chen G, Seyfried NT, Chazin WJ, Kiyokawa H, Yin J
(2018) Sci Adv 4: e1701393
MeSH Terms: Amino Acid Sequence, Bacteriophages, Biocatalysis, Cyclin-Dependent Kinase 4, Endoplasmic Reticulum Stress, HEK293 Cells, Humans, Mutant Proteins, Mutation, Peptides, Proteolysis, Reproducibility of Results, Signal Transduction, Substrate Specificity, Tumor Suppressor Protein p53, Tumor Suppressor Proteins, Ubiquitin, Ubiquitin-Protein Ligase Complexes, Ubiquitin-Protein Ligases, Ubiquitination
Show Abstract · Added March 24, 2018
E3 ubiquitin (UB) ligases E4B and carboxyl terminus of Hsc70-interacting protein (CHIP) use a common U-box motif to transfer UB from E1 and E2 enzymes to their substrate proteins and regulate diverse cellular processes. To profile their ubiquitination targets in the cell, we used phage display to engineer E2-E4B and E2-CHIP pairs that were free of cross-reactivity with the native UB transfer cascades. We then used the engineered E2-E3 pairs to construct "orthogonal UB transfer (OUT)" cascades so that a mutant UB (xUB) could be exclusively used by the engineered E4B or CHIP to label their substrate proteins. Purification of xUB-conjugated proteins followed by proteomics analysis enabled the identification of hundreds of potential substrates of E4B and CHIP in human embryonic kidney 293 cells. Kinase MAPK3 (mitogen-activated protein kinase 3), methyltransferase PRMT1 (protein arginine -methyltransferase 1), and phosphatase PPP3CA (protein phosphatase 3 catalytic subunit alpha) were identified as the shared substrates of the two E3s. Phosphatase PGAM5 (phosphoglycerate mutase 5) and deubiquitinase OTUB1 (ovarian tumor domain containing ubiquitin aldehyde binding protein 1) were confirmed as E4B substrates, and β-catenin and CDK4 (cyclin-dependent kinase 4) were confirmed as CHIP substrates. On the basis of the CHIP-CDK4 circuit identified by OUT, we revealed that CHIP signals CDK4 degradation in response to endoplasmic reticulum stress.
0 Communities
1 Members
0 Resources
20 MeSH Terms
Set2 methyltransferase facilitates cell cycle progression by maintaining transcriptional fidelity.
Dronamraju R, Jha DK, Eser U, Adams AT, Dominguez D, Choudhury R, Chiang YC, Rathmell WK, Emanuele MJ, Churchman LS, Strahl BD
(2018) Nucleic Acids Res 46: 1331-1344
MeSH Terms: Anaphase-Promoting Complex-Cyclosome, Biological Evolution, Cdc20 Proteins, Cell Cycle, Gene Expression Regulation, Fungal, Histone-Lysine N-Methyltransferase, Histones, Humans, Lysine, Methylation, Methyltransferases, Nocodazole, Protein Processing, Post-Translational, Proteolysis, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Transcription, Genetic, Tubulin Modulators
Show Abstract · Added October 30, 2019
Methylation of histone H3 lysine 36 (H3K36me) by yeast Set2 is critical for the maintenance of chromatin structure and transcriptional fidelity. However, we do not know the full range of Set2/H3K36me functions or the scope of mechanisms that regulate Set2-dependent H3K36 methylation. Here, we show that the APC/CCDC20 complex regulates Set2 protein abundance during the cell cycle. Significantly, absence of Set2-mediated H3K36me causes a loss of cell cycle control and pronounced defects in the transcriptional fidelity of cell cycle regulatory genes, a class of genes that are generally long, hence highly dependent on Set2/H3K36me for their transcriptional fidelity. Because APC/C also controls human SETD2, and SETD2 likewise regulates cell cycle progression, our data imply an evolutionarily conserved cell cycle function for Set2/SETD2 that may explain why recurrent mutations of SETD2 contribute to human disease.
0 Communities
1 Members
0 Resources
MeSH Terms
Dynamic landscape and regulation of RNA editing in mammals.
Tan MH, Li Q, Shanmugam R, Piskol R, Kohler J, Young AN, Liu KI, Zhang R, Ramaswami G, Ariyoshi K, Gupte A, Keegan LP, George CX, Ramu A, Huang N, Pollina EA, Leeman DS, Rustighi A, Goh YPS, GTEx Consortium, Laboratory, Data Analysis &Coordinating Center (LDACC)—Analysis Working Group, Statistical Methods groups—Analysis Working Group, Enhancing GTEx (eGTEx) groups, NIH Common Fund, NIH/NCI, NIH/NHGRI, NIH/NIMH, NIH/NIDA, Biospecimen Collection Source Site—NDRI, Biospecimen Collection Source Site—RPCI, Biospecimen Core Resource—VARI, Brain Bank Repository—University of Miami Brain Endowment Bank, Leidos Biomedical—Project Management, ELSI Study, Genome Browser Data Integration &Visualization—EBI, Genome Browser Data Integration &Visualization—UCSC Genomics Institute, University of California Santa Cruz, Chawla A, Del Sal G, Peltz G, Brunet A, Conrad DF, Samuel CE, O'Connell MA, Walkley CR, Nishikura K, Li JB
(2017) Nature 550: 249-254
MeSH Terms: Adenosine Deaminase, Animals, Female, Genotype, HEK293 Cells, Humans, Male, Mice, Muscles, Nuclear Proteins, Organ Specificity, Primates, Proteolysis, RNA Editing, RNA-Binding Proteins, Spatio-Temporal Analysis, Species Specificity, Transcriptome
Show Abstract · Added October 27, 2017
Adenosine-to-inosine (A-to-I) RNA editing is a conserved post-transcriptional mechanism mediated by ADAR enzymes that diversifies the transcriptome by altering selected nucleotides in RNA molecules. Although many editing sites have recently been discovered, the extent to which most sites are edited and how the editing is regulated in different biological contexts are not fully understood. Here we report dynamic spatiotemporal patterns and new regulators of RNA editing, discovered through an extensive profiling of A-to-I RNA editing in 8,551 human samples (representing 53 body sites from 552 individuals) from the Genotype-Tissue Expression (GTEx) project and in hundreds of other primate and mouse samples. We show that editing levels in non-repetitive coding regions vary more between tissues than editing levels in repetitive regions. Globally, ADAR1 is the primary editor of repetitive sites and ADAR2 is the primary editor of non-repetitive coding sites, whereas the catalytically inactive ADAR3 predominantly acts as an inhibitor of editing. Cross-species analysis of RNA editing in several tissues revealed that species, rather than tissue type, is the primary determinant of editing levels, suggesting stronger cis-directed regulation of RNA editing for most sites, although the small set of conserved coding sites is under stronger trans-regulation. In addition, we curated an extensive set of ADAR1 and ADAR2 targets and showed that many editing sites display distinct tissue-specific regulation by the ADAR enzymes in vivo. Further analysis of the GTEx data revealed several potential regulators of editing, such as AIMP2, which reduces editing in muscles by enhancing the degradation of the ADAR proteins. Collectively, our work provides insights into the complex cis- and trans-regulation of A-to-I editing.
0 Communities
1 Members
0 Resources
18 MeSH Terms
Defining the interaction of the protease CpaA with its type II secretion chaperone CpaB and its contribution to virulence in species.
Kinsella RL, Lopez J, Palmer LD, Salinas ND, Skaar EP, Tolia NH, Feldman MF
(2017) J Biol Chem 292: 19628-19638
MeSH Terms: Acinetobacter, Animals, Factor V, Larva, Mice, Mice, Inbred C57BL, Molecular Chaperones, Peptide Hydrolases, Protein Binding, Proteolysis, Spleen, Virulence
Show Abstract · Added March 15, 2018
, , and are a frequent cause of multidrug-resistant, healthcare-associated infections. Our previous work demonstrated that M2 possesses a functional type II secretion system (T2SS) that is required for full virulence. Further, we identified the metallo-endopeptidase CpaA, which has been shown previously to cleave human Factor V and deregulate blood coagulation, as the most abundant type II secreted effector protein. We also demonstrated that its secretion is dependent on CpaB, a membrane-bound chaperone. In this study, we show that CpaA expression and secretion are conserved across several medically relevant species. Additionally, we demonstrate that deletion of results in attenuation of M2 virulence in moth and mouse models. The virulence defects resulting from the deletion of were comparable with those observed upon abrogation of T2SS activity. The virulence defects resulting from the deletion of are comparable with those observed upon abrogation of T2SS activity. We also show that CpaA and CpaB strongly interact, forming a complex in a 1:1 ratio. Interestingly, deletion of the N-terminal transmembrane domain of CpaB results in robust secretion of CpaA and CpaB, indicating that the transmembrane domain is dispensable for CpaA secretion and likely functions to retain CpaB inside the cell. Limited proteolysis of spheroplasts revealed that the C-terminal domain of CpaB is exposed to the periplasm, suggesting that this is the site where CpaA and CpaB interact Last, we show that CpaB does not abolish the proteolytic activity of CpaA against human Factor V. We conclude that CpaA is, to the best of our knowledge, the first characterized, virulence factor secreted by species.
© 2017 by The American Society for Biochemistry and Molecular Biology, Inc.
0 Communities
1 Members
0 Resources
12 MeSH Terms