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Biochemistry, Biophysics, and Structural Biology Commons

Open Access. Powered by Scholars. Published by Universities.®

Molecular Biology

2011

University of Massachusetts Medical School

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Articles 1 - 13 of 13

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

The Loss Of C-Jun N-Terminal Protein Kinase Activity Prevents The Amyloidogenic Cleavage Of Amyloid Precursor Protein And The Formation Of Amyloid Plaques In Vivo, Sonia Mazzitelli, Ping Xu, Isidre Ferrer, Roger J. Davis, Cathy Tournier Nov 2011

The Loss Of C-Jun N-Terminal Protein Kinase Activity Prevents The Amyloidogenic Cleavage Of Amyloid Precursor Protein And The Formation Of Amyloid Plaques In Vivo, Sonia Mazzitelli, Ping Xu, Isidre Ferrer, Roger J. Davis, Cathy Tournier

Davis Lab Publications

Phosphorylation plays a central role in the dynamic regulation of the processing of the amyloid precursor protein (APP) and the production of amyloid-beta (Abeta), one of the clinically most important factors that determine the onset of Alzheimer's disease (AD). This has led to the hypothesis that aberrant Abeta production associated with AD results from regulatory defects in signal transduction. However, conflicting findings have raised a debate over the identity of the signaling pathway that controls APP metabolism. Here, we demonstrate that activation of the c-Jun N-terminal protein kinase (JNK) is essential for mediating the apoptotic response of neurons to ...


Mlk3 Regulates Bone Development Downstream Of The Faciogenital Dysplasia Protein Fgd1 In Mice, Weiguo Zou, Matthew B. Greenblatt, Jae-Hyuck Shim, Shashi Kant, Bo Zhai, Sutada Lotinun, Nicholas Brady, Dorothy Zhang Hu, Steven P. Gygi, Roland Baron, Roger J. Davis, Dallas Jones, Laurie H. Glimcher Nov 2011

Mlk3 Regulates Bone Development Downstream Of The Faciogenital Dysplasia Protein Fgd1 In Mice, Weiguo Zou, Matthew B. Greenblatt, Jae-Hyuck Shim, Shashi Kant, Bo Zhai, Sutada Lotinun, Nicholas Brady, Dorothy Zhang Hu, Steven P. Gygi, Roland Baron, Roger J. Davis, Dallas Jones, Laurie H. Glimcher

Davis Lab Publications

Mutations in human FYVE, RhoGEF, and PH domain-containing 1 (FGD1) cause faciogenital dysplasia (FGDY; also known as Aarskog syndrome), an X-linked disorder that affects multiple skeletal structures. FGD1 encodes a guanine nucleotide exchange factor (GEF) that specifically activates the Rho GTPase CDC42. However, the mechanisms by which mutations in FGD1 affect skeletal development are unknown. Here, we describe what we believe to be a novel signaling pathway in osteoblasts initiated by FGD1 that involves the MAP3K mixed-lineage kinase 3 (MLK3). We observed that MLK3 functions downstream of FGD1 to regulate ERK and p38 MAPK, which in turn phosphorylate and activate ...


Tnf-Stimulated Map Kinase Activation Mediated By A Rho Family Gtpase Signaling Pathway, Shashi Kant, Wojciech Swat, Sheng Zhang, Zhong-Yin Zhang, Benjamin G. Neel, Richard A. Flavell, Roger J. Davis Oct 2011

Tnf-Stimulated Map Kinase Activation Mediated By A Rho Family Gtpase Signaling Pathway, Shashi Kant, Wojciech Swat, Sheng Zhang, Zhong-Yin Zhang, Benjamin G. Neel, Richard A. Flavell, Roger J. Davis

Davis Lab Publications

The biological response to tumor necrosis factor (TNF) involves activation of MAP kinases. Here we report a mechanism of MAP kinase activation by TNF that is mediated by the Rho GTPase family members Rac/Cdc42. This signaling pathway requires Src-dependent activation of the guanosine nucleotide exchange factor Vav, activation of Rac/Cdc42, and the engagement of the Rac/Cdc42 interaction site (CRIB motif) on mixed-lineage protein kinases (MLKs). We show that this pathway is essential for full MAP kinase activation during the response to TNF. Moreover, this MLK pathway contributes to inflammation in vivo.


A Brain-Derived Mecp2 Complex Supports A Role For Mecp2 In Rna Processing, Steven W. Long, Jenny Y. Y. Ooi, Peter M. Yau, Peter L. Jones Oct 2011

A Brain-Derived Mecp2 Complex Supports A Role For Mecp2 In Rna Processing, Steven W. Long, Jenny Y. Y. Ooi, Peter M. Yau, Peter L. Jones

Peter Jones Lab Publications

Mutations in MECP2 (methyl-CpG-binding protein 2) are linked to the severe postnatal neurodevelopmental disorder RTT (Rett syndrome). MeCP2 was originally characterized as a transcriptional repressor that preferentially bound methylated DNA; however, recent results indicate MeCP2 is a multifunctional protein. MeCP2 binding is now associated with certain expressed genes and involved in nuclear organization as well, indicating that its gene regulatory function is context-dependent. In addition, MeCP2 is proposed to regulate mRNA splicing and a mouse model for RTT shows aberrant mRNA splicing. To further understand MeCP2 and potential roles in RTT pathogenesis, we have employed a biochemical approach to identify ...


Drosophila Iap1-Mediated Ubiquitylation Controls Activation Of The Initiator Caspase Dronc Independent Of Protein Degradation, Tom V. Lee, Yun Fan, Shiuan Wang, Mayank Srivastava, Meike Broemer, Pascal Meier, Andreas Bergmann Sep 2011

Drosophila Iap1-Mediated Ubiquitylation Controls Activation Of The Initiator Caspase Dronc Independent Of Protein Degradation, Tom V. Lee, Yun Fan, Shiuan Wang, Mayank Srivastava, Meike Broemer, Pascal Meier, Andreas Bergmann

Molecular, Cell and Cancer Biology Publications

Ubiquitylation targets proteins for proteasome-mediated degradation and plays important roles in many biological processes including apoptosis. However, non-proteolytic functions of ubiquitylation are also known. In Drosophila, the inhibitor of apoptosis protein 1 (DIAP1) is known to ubiquitylate the initiator caspase DRONC in vitro. Because DRONC protein accumulates in diap1 mutant cells that are kept alive by caspase inhibition ("undead" cells), it is thought that DIAP1-mediated ubiquitylation causes proteasomal degradation of DRONC, protecting cells from apoptosis. However, contrary to this model, we show here that DIAP1-mediated ubiquitylation does not trigger proteasomal degradation of full-length DRONC, but serves a non-proteolytic function. Our ...


Temporal Uncoupling Of The Dna Methylome And Transcriptional Repression During Embryogenesis, Ozren Bogdanovic, Steven W. Long, Simon J. Van Heeringen, Arie B. Brinkman, Jose Luis Gomez-Skarmeta, Hendrik G. Stunnenberg, Peter L. Jones, Gert Jan C. Veenstra Aug 2011

Temporal Uncoupling Of The Dna Methylome And Transcriptional Repression During Embryogenesis, Ozren Bogdanovic, Steven W. Long, Simon J. Van Heeringen, Arie B. Brinkman, Jose Luis Gomez-Skarmeta, Hendrik G. Stunnenberg, Peter L. Jones, Gert Jan C. Veenstra

Peter Jones Lab Publications

DNA methylation is a tightly regulated epigenetic mark associated with transcriptional repression. Next-generation sequencing of purified methylated DNA obtained from early Xenopus tropicalis embryos demonstrates that this genome is heavily methylated during blastula and gastrula stages. Although DNA methylation is largely absent from transcriptional start sites marked with histone H3 lysine 4 trimethylation (H3K4me3), we find both promoters and gene bodies of active genes robustly methylated. In contrast, DNA methylation is absent in large H3K27me3 domains, indicating that these two repression pathways have different roles. Comparison with chromatin state maps of human ES cells reveals strong conservation of epigenetic makeup ...


Activated Innate Immunity In Childhood: A Novel Treatment Target, Olga T. Hardy May 2011

Activated Innate Immunity In Childhood: A Novel Treatment Target, Olga T. Hardy

UMass Center for Clinical and Translational Science Research Retreat

Obesity is a state of chronic low grade inflammation with elevated cytokines that contribute to obesity-related co-morbidities. This presentation will include an overview of a Life Sciences Moment Fund project that examined the effects of a multi-component wellness intervention designed to increase physical activity and reduce risk for cardiometabolic disease in overweight adolescents. Selected results suggesting the potential of activated innate immunity in childhood as a novel treatment target will be emphasized.


Requirement Of C-Jun Nh(2)-Terminal Kinase For Ras-Initiated Tumor Formation, Cristina Arrigo Cellurale, Guadalupe Sabio, Norman J. Kennedy, Madhumita Das, Marissa Bylsma, Peter Sandy, Tyler Jacks, Roger J. Davis Apr 2011

Requirement Of C-Jun Nh(2)-Terminal Kinase For Ras-Initiated Tumor Formation, Cristina Arrigo Cellurale, Guadalupe Sabio, Norman J. Kennedy, Madhumita Das, Marissa Bylsma, Peter Sandy, Tyler Jacks, Roger J. Davis

Davis Lab Publications

The c-Jun NH(2)-terminal kinase (JNK) signal transduction pathway causes increased gene expression mediated, in part, by members of the activating transcription factor protein (AP1) group. JNK is therefore implicated in the regulation of cell growth and cancer. To test the role of JNK in Ras-induced tumor formation, we examined the effect of compound ablation of the ubiquitously expressed genes Jnk1 plus Jnk2. We report that JNK is required for Ras-induced transformation of p53-deficient primary cells in vitro. Moreover, JNK is required for lung tumor development caused by mutational activation of the endogenous KRas gene in vivo. Together, these ...


Effect Of Life History On Microrna Expression During C. Elegans Development, Xantha Karp, Molly Hammell, Maria C. Ow, Victor R. Ambros Apr 2011

Effect Of Life History On Microrna Expression During C. Elegans Development, Xantha Karp, Molly Hammell, Maria C. Ow, Victor R. Ambros

Program in Molecular Medicine Publications and Presentations

Animals have evolved mechanisms to ensure the robustness of developmental outcomes to changing environments. MicroRNA expression may contribute to developmental robustness because microRNAs are key post-transcriptional regulators of developmental gene expression and can affect the expression of multiple target genes. Caenorhabditis elegans provides an excellent model to study developmental responses to environmental conditions. In favorable environments, C. elegans larvae develop rapidly and continuously through four larval stages. In contrast, in unfavorable conditions, larval development may be interrupted at either of two diapause stages: The L1 diapause occurs when embryos hatch in the absence of food, and the dauer diapause occurs ...


The Role Of Jnk In The Development Of Hepatocellular Carcinoma, Madhumita Das, David S. Garlick, Dale Greiner, Roger J. Davis Mar 2011

The Role Of Jnk In The Development Of Hepatocellular Carcinoma, Madhumita Das, David S. Garlick, Dale Greiner, Roger J. Davis

Davis Lab Publications

The cJun NH(2)-terminal kinase (JNK) signal transduction pathway has been implicated in the growth of carcinogen-induced hepatocellular carcinoma. However, the mechanism that accounts for JNK-regulated tumor growth is unclear. Here we demonstrate that compound deficiency of the two ubiquitously expressed JNK isoforms (JNK1 and JNK2) in hepatocytes does not prevent hepatocellular carcinoma development. Indeed, JNK deficiency in hepatocytes increased the tumor burden. In contrast, compound JNK deficiency in hepatocytes and nonparenchymal cells reduced both hepatic inflammation and tumorigenesis. These data indicate that JNK plays a dual role in the development of hepatocellular carcinoma. JNK promotes an inflammatory hepatic ...


Establishment Of Clonal Myogenic Cell Lines From Severely Affected Dystrophic Muscles - Cdk4 Maintains The Myogenic Population, Guido Stadler, Jennifer Cj Chen, Kathryn Wagner, Jerome D. Robin, Jerry W. Shay, Charles P. Emerson, Jr., Woodring E. Wright Mar 2011

Establishment Of Clonal Myogenic Cell Lines From Severely Affected Dystrophic Muscles - Cdk4 Maintains The Myogenic Population, Guido Stadler, Jennifer Cj Chen, Kathryn Wagner, Jerome D. Robin, Jerry W. Shay, Charles P. Emerson, Jr., Woodring E. Wright

Wellstone Center for FSHD Publications

BACKGROUND: A hallmark of muscular dystrophies is the replacement of muscle by connective tissue. Muscle biopsies from patients severely affected with facioscapulohumeral muscular dystrophy (FSHD) may contain few myogenic cells. Because the chromosomal contraction at 4q35 linked to FSHD is thought to cause a defect within myogenic cells, it is important to study this particular cell type, rather than the fibroblasts and adipocytes of the endomysial fibrosis, to understand the mechanism leading to myopathy.

RESULTS: We present a protocol to establish clonal myogenic cell lines from even severely dystrophic muscle that has been replaced mostly by fat, using overexpression of ...


Jnk Regulates Foxo-Dependent Autophagy In Neurons, Ping Xu, Madhumita Das, Judith Reilly, Roger J. Davis Feb 2011

Jnk Regulates Foxo-Dependent Autophagy In Neurons, Ping Xu, Madhumita Das, Judith Reilly, Roger J. Davis

Davis Lab Publications

The cJun N-terminal kinase (JNK) signal transduction pathway is implicated in the regulation of neuronal function. JNK is encoded by three genes that play partially redundant roles. Here we report the creation of mice with targeted ablation of all three Jnk genes in neurons. Compound JNK-deficient neurons are dependent on autophagy for survival. This autophagic response is caused by FoxO-induced expression of Bnip3 that displaces the autophagic effector Beclin-1 from inactive Bcl-XL complexes. These data identify JNK as a potent negative regulator of FoxO-dependent autophagy in neurons.


Target Rna-Directed Tailing And Trimming Purifies The Sorting Of Endo-Sirnas Between The Two Drosophila Argonaute Proteins, Stefan L. Ameres, Jui-Hung Hung, Jia Xu, Zhiping Weng, Phillip D. Zamore Jan 2011

Target Rna-Directed Tailing And Trimming Purifies The Sorting Of Endo-Sirnas Between The Two Drosophila Argonaute Proteins, Stefan L. Ameres, Jui-Hung Hung, Jia Xu, Zhiping Weng, Phillip D. Zamore

Program in Bioinformatics and Integrative Biology Publications and Presentations

In flies, 22-23-nucleotide (nt) microRNA duplexes typically contain mismatches and begin with uridine, so they bind Argonaute1 (Ago1), whereas 21-nt siRNA duplexes are perfectly paired and begin with cytidine, promoting their loading into Ago2. A subset of Drosophila endogenous siRNAs-the hairpin-derived hp-esiRNAs-are born as mismatched duplexes that often begin with uridine. These would be predicted to load into Ago1, yet accumulate at steady-state bound to Ago2. In vitro, such hp-esiRNA duplexes assemble into Ago1. In vivo, they encounter complementary target mRNAs that trigger their tailing and trimming, causing Ago1-loaded hp-esiRNAs to be degraded. In contrast, Ago2-associated hp-esiRNAs are 2'-O-methyl ...