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Biochemistry, Biophysics, and Structural Biology Commons

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Physiology

2011

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Articles 1 - 9 of 9

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 ...


A Lipid-Anchored Snare Supports Membrane Fusion, Hao Xu, Michael Zick, William T. Wickner, Youngsoo Jun Oct 2011

A Lipid-Anchored Snare Supports Membrane Fusion, Hao Xu, Michael Zick, William T. Wickner, Youngsoo Jun

Open Dartmouth: Faculty Open Access Scholarship

Intracellular membrane fusion requires R-SNAREs and Q-SNAREs to assemble into a four-helical parallel coiled-coil, with their hydrophobic anchors spanning the two apposed membranes. Based on the fusion properties of chemically defined SNARE- proteoliposomes, it has been proposed that the assembly of this helical bundle transduces force through the entire bilayer via the transmembrane SNARE anchor domains to drive fusion. However, an R-SNARE, Nyv1p, with a genetically engineered lipid anchor that spans half of the bilayer suffices for the fusion of isolated vacuoles, although this organelle has other R-SNAREs. To demonstrate unequivocally the fusion activity of lipid-anchored Nyv1p, we reconstituted proteoliposomes ...


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.


Interspecies Comparison Of Αii-Spectrin Abundance Between Chinook Salmon And Steelhead, Brielle D. Kemis, Ann L. Miracle, Katie A. Wagner, Christa M. Woodley Aug 2011

Interspecies Comparison Of Αii-Spectrin Abundance Between Chinook Salmon And Steelhead, Brielle D. Kemis, Ann L. Miracle, Katie A. Wagner, Christa M. Woodley

STAR (STEM Teacher and Researcher) Presentations

Salmonids, such as Chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss), are a staple economic, recreational, tribal, and environmental resource, yet many populations are unsustainable. This study was part of a broad scale effort to monitor the impact of downstream migration obstacles on juvenile salmonid health and survival, which is an essential step towards increasing Smolt-to-Adult Return ratios (SARs). The objective of this study was to determine if juvenile Chinook salmon and steelhead exhibit differing quantities of alphaII-Spectrin Breakdown Products (SBDPs) over two consecutive spring migration periods, indicative of neurogenesis rate and/or biological response to head injury. AlphaII-Spectrin is ...


Physiologically-Based Pharmacokinetic Modeling For Predicting Drug-Drug Interactions, David M. Ng, Ali Navid Aug 2011

Physiologically-Based Pharmacokinetic Modeling For Predicting Drug-Drug Interactions, David M. Ng, Ali Navid

STAR (STEM Teacher and Researcher) Presentations

Dynamics of interactions between the drugs caffeine and ciprofloxacin are predicted using physiologically-based pharmacokinetic (PBPK) modeling. Pharmacokinetic means the model determines where the drugs are distributed in the body over time. Physiologically-based means the anatomy and physiology of the human body is reflected in the structure and functioning of the model. Multiple drugs can interact to increase or decrease their beneficial and/or undesired effects. This is important because some common substances, such as caffeine in coffee and soft drinks, are actually drugs that affect the body. By implementing the model as a computer program, it is relatively straightforward to ...


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 ...


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 ...


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.