IU Indianapolis ScholarWorks :: Browsing by Subject "Protein-Serine-Threonine Kinases"

Browsing by Subject "Protein-Serine-Threonine Kinases"

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60kDa Lysophospholipase, a New Sgk1 Molecular Partner Involved in the Regulation of ENaC
(2010) Menniti, Miranda; Iuliano, Rodolfo; Föller, Michael; Sopjani, Mentor; Alesutan, Ioana; Mariggiò, Stefania; Nofziger, Charity; Perri, Angela M.; Amato, Rosario; Blazer-Yost, Bonnie; Corda, Daniela; Lang, Florian; Perrotti, Nicola
The serum- and glucocorticoid-regulated kinase (Sgk1) is essential for hormonal regulation of ENaC-mediated sodium transport and is involved in the transduction of growth-factor-dependent cell survival and proliferation. The identification of molecular partners for Sgk1 is crucial for the understanding of its mechanisms of action. We performed a yeast two-hybrid screening based on a human kidney cDNA library to identify molecular partners of Sgk1. As a result the screening revealed a specific interaction between Sgk1 and a 60 kDa Lysophospholipase (LysoLP). LysoLP is a poorly characterized enzyme that, based on sequence analysis, might possess lysophospholipase and asparaginase activities. We demonstrate that LysoLP has indeed a lysophospholipase activity and affects metabolic functions related to cell proliferation and regulation of membrane channels. Moreover we demonstrate in the Xenopus oocyte expression system that LysoLP downregulates basal and Sgk1-dependent ENaC activity. In conclusion LysoLP may represent a new player in the regulation of ENaC and Sgk1-dependent signaling.
Designing Visible Light-Cured Thiol-Acrylate Hydrogels for Studying the HIPPO Pathway Activation in Hepatocellular Carcinoma Cells
(Wiley Blackwell (John Wiley & Sons), 2016-04) Lin, Tsai-Yu; Bragg, John C.; Lin, Chien-Chi; Department of Biomedical Engineering, School of Engineering and Technology
Various polymerization mechanisms have been developed to prepare peptide-immobilized poly(ethylene glycol) (PEG) hydrogels, a class of biomaterials suitable for studying cell biology in vitro. Here, a visible light mediated thiol-acrylate photopolymerization scheme is reported to synthesize dually degradable PEG-peptide hydrogels with controllable crosslinking and degradability. The influence of immobilized monothiol pendant peptide is systematically evaluated on the crosslinking of these hydrogels. Further, methods are proposed to modulate hydrogel crosslinking, including adjusting concentration of comonomer or altering the design of multifunctional peptide crosslinker. Due to the formation of thioether ester bonds, these hydrogels are hydrolytically degradable. If the dithiol peptide linkers used are susceptible to protease cleavage, these thiol-acrylate hydrogels can be designed to undergo partial proteolysis. The differences between linear and multiarm PEG-acrylate (i.e., PEGDA vs PEG4A) are also evaluated. Finally, the use of the mixed-mode thiol-acrylate PEG4A-peptide hydrogels is explored for in situ encapsulation of hepatocellular carcinoma cells (Huh7). The effects of matrix stiffness and integrin binding motif (e.g., RGDS) on Huh7 cell growth and HIPPO pathway activation are studied using PEG4A-peptide hydrogels. This visible light poly-merized thiol-acrylate hydrogel system represents an alternative to existing light-cured hydrogel platforms and shall be useful in many biomedical applications.
Endoplasmic Reticulum Stress Activates the Inflammasome via NLRP3- and Caspase-2-Driven Mitochondrial Damage
(Elsevier, 2015-09-15) Bronner, Denise N.; Abuaita, Basel H.; Chen, Xiaoyun; Fitzgerald, Katherine A.; Nuñez, Gabriel; He, Yongqun; Yin, Xiao-Ming; O’Riordan, Mary X.D.; Department of Pathology and Laboratory Medicine, IU School of Medicine
Endoplasmic reticulum (ER) stress is observed in many human diseases, often associated with inflammation. ER stress can trigger inflammation through nucleotide-binding domain and leucine-rich repeat containing (NLRP3) inflammasome, which might stimulate inflammasome formation by association with damaged mitochondria. How ER stress triggers mitochondrial dysfunction and inflammasome activation is ill defined. Here we have used an infection model to show that the IRE1α ER stress sensor regulates regulated mitochondrial dysfunction through an NLRP3-mediated feed-forward loop, independently of ASC. IRE1α activation increased mitochondrial reactive oxygen species, promoting NLRP3 association with mitochondria. NLRP3 was required for ER stress-induced cleavage of caspase-2 and the pro-apoptotic factor, Bid, leading to subsequent release of mitochondrial contents. Caspase-2 and Bid were necessary for activation of the canonical inflammasome by infection-associated or general ER stress. These data identify an NLRP3-caspase-2-dependent mechanism that relays ER stress to the mitochondria to promote inflammation, integrating cellular stress and innate immunity.
FASTKD2 and human memory: functional pathways and prospects for novel therapeutic target development for Alzheimer's disease and age-associated memory decline
(Future Medicine, 2015) Ramanan, Vijay K.; Saykin, Andrew J.; Department of Radiology and Imaging Sciences, IU School of Medicine
FASTKD2 is associated with memory and hippocampal structure in older adults
(Nature Publishing Group, 2015-10) Ramanan, Vijay K.; Nho, Kwangsik; Shen, Li; Risacher, Shannon L.; Kim, Sungeun; McDonald, Brenna C.; Farlow, Martin R.; Foroud, Tatiana M.; Gao, Sujuan; Soininen, Hilkka; Kłoszewska, Iwona; Mecocci, Patrizia; Tsolaki, Magda; Vellas, Bruno; Lovestone, Simon; Aisen, Paul S.; Petersen, Ronald C.; Jack, Clifford R.; Shaw, Leslie M.; Trojanowski, John Q.; Weiner, Michael W.; Green, Robert C.; Toga, Arthur W.; De Jager, Philip L.; Yu, Lei; Bennett, David A.; Saykin, Andrew J.; Department of Radiology and Imaging Sciences, IU School of Medicine
Memory impairment is the cardinal early feature of Alzheimer's disease, a highly prevalent disorder whose causes remain only partially understood. To identify novel genetic predictors, we used an integrative genomics approach to perform the largest study to date of human memory (n=14 781). Using a genome-wide screen, we discovered a novel association of a polymorphism in the pro-apoptotic gene FASTKD2 (fas-activated serine/threonine kinase domains 2; rs7594645-G) with better memory performance and replicated this finding in independent samples. Consistent with a neuroprotective effect, rs7594645-G carriers exhibited increased hippocampal volume and gray matter density and decreased cerebrospinal fluid levels of apoptotic mediators. The MTOR (mechanistic target of rapamycin) gene and pathways related to endocytosis, cholinergic neurotransmission, epidermal growth factor receptor signaling and immune regulation, among others, also displayed association with memory. These findings nominate FASTKD2 as a target for modulating neurodegeneration and suggest potential mechanisms for therapies to combat memory loss in normal cognitive aging and dementia.
Influence of prenatal EGCG treatment and Dyrk1a dosage reduction on craniofacial features associated with Down syndrome
(Oxford Academic, 2016-11-15) McElyea, Samantha D.; Starbuck, John M.; Tumbleson-Brink, Danika M.; Harrington, Emily; Blazek, Joshua D.; Ghoneima, Ahmed; Kula, Katherine; Roper, Randall J.; Biology, School of Science
Trisomy 21 (Ts21) affects craniofacial precursors in individuals with Down syndrome (DS). The resultant craniofacial features in all individuals with Ts21 may significantly affect breathing, eating and speaking. Using mouse models of DS, we have traced the origin of DS-associated craniofacial abnormalities to deficiencies in neural crest cell (NCC) craniofacial precursors early in development. Hypothetically, three copies of Dyrk1a (dual-specificity tyrosine-(Y)-phosphorylation regulated kinase 1A), a trisomic gene found in most humans with DS and mouse models of DS, may significantly affect craniofacial structure. We hypothesized that we could improve DS-related craniofacial abnormalities in mouse models using a Dyrk1a inhibitor or by normalizing Dyrk1a gene dosage. In vitro and in vivo treatment with Epigallocatechin-3-gallate (EGCG), a Dyrk1a inhibitor, modulated trisomic NCC deficiencies at embryonic time points. Furthermore, prenatal EGCG treatment normalized some craniofacial phenotypes, including cranial vault in adult Ts65Dn mice. Normalization of Dyrk1a copy number in an otherwise trisomic Ts65Dn mice normalized many dimensions of the cranial vault, but did not correct all craniofacial anatomy. These data underscore the complexity of the gene–phenotype relationship in trisomy and suggest that changes in Dyrk1a expression play an important role in morphogenesis and growth of the cranial vault. These results suggest that a temporally specific prenatal therapy may be an effective way to ameliorate some craniofacial anatomical changes associated with DS.
Lack of the serum and glucocorticoid-inducible kinase SGK1 attenuates the volume retention after treatment with the PPARγ agonist pioglitazone
(2008-05) Artunc, Ferruh; Sandulache, Diana; Nasir, Omaima; Boini, Krishna M.; Friedrich, Björn; Beier, Norbert; Dicks, Edith; Pötzsch, Sven; Klingel, Karin; Amann, Kerstin; Blazer-Yost, Bonnie; Scholz, Wolfgang; Risler, Teut; Kuhl, Dietmar; Lang, Florian
PPARgamma-agonists enhance insulin sensitivity and improve glucose utilization in diabetic patients. Adverse effects of PPARgamma-agonists include volume retention and edema formation. Recent observations pointed to the ability of PPARgamma agonists to enhance transcription of the serum and glucocorticoid-inducible kinase SGK1, a kinase that is genomically upregulated by mineralocorticoids and stimulates various renal channels and transporters including the renal epithelial Na+ channel ENaC. SGK1 has been proposed to mediate the volume retention after treatment with PPARgamma agonists. To test this hypothesis, food containing the PPARgamma agonist pioglitazone (0.02%, i.e., approximately 25 mg/kg bw/day) was administered to gene-targeted mice lacking SGK1 (sgk1-/-, n=12) and their wild-type littermates (sgk1+/+), n=12). According to in situ hybridization, quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and immunofluorescence, treatment with pioglitazone significantly increased renal SGK1 mRNA and protein expression in sgk1+/+ mice. The treatment increased body weight significantly in both, sgk1+/+ mice (+2.2+/-0.3 g) and sgk-/- mice (+1.3+/-0.2 g), and decreased hematocrit significantly in sgk1+/+ mice (-6.5+/-1.0%) and sgk1-/- mice (-3.1+/-0.6%). Both effects were significantly (p<0.05) more pronounced in sgk1+/+ mice. According to Evans Blue distribution, pioglitazone increased plasma volume only in sgk1+/+ mice (from 50.9+/-3.9 to 63.7+/-2.5 microl/g bw) but not in sgk-/- mice (from 46.8+/-3.8 to 48.3+/-5.2 microl/g bw). Pioglitazone decreased aldosterone plasma levels and blood pressure and increased leptin plasma levels in both genotypes. We conclude that SGK1 contributes to but does not fully account for the volume retention during treatment with the PPARgamma agonist pioglitazone.
A proteasome-resistant fragment of NIK mediates oncogenic NF-κB signaling in schwannomas
(Oxford University Press, 2019-02-15) Gehlhausen, Jeffrey R.; Hawley, Eric; Wahle, Benjamin Mark; He, Yongzheng; Edwards, Donna; Rhodes, Steven D.; Lajiness, Jacquelyn D.; Staser, Karl; Chen, Shi; Yang, Xianlin; Yuan, Jin; Li, Xiaohong; Jiang, Li; Smith, Abbi; Bessler, Waylan; Sandusky, George; Stemmer-Rachamimov, Anat; Stuhlmiller, Timothy J.; Angus, Steven P.; Johnson, Gary L.; Nalepa, Grzegorz; Yates, Charles W.; Clapp, D. Wade; Park, Su-Jung; Pediatrics, School of Medicine
Schwannomas are common, highly morbid and medically untreatable tumors that can arise in patients with germ line as well as somatic mutations in neurofibromatosis type 2 (NF2). These mutations most commonly result in the loss of function of the NF2-encoded protein, Merlin. Little is known about how Merlin functions endogenously as a tumor suppressor and how its loss leads to oncogenic transformation in Schwann cells (SCs). Here, we identify nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB)-inducing kinase (NIK) as a potential drug target driving NF-κB signaling and Merlin-deficient schwannoma genesis. Using a genomic approach to profile aberrant tumor signaling pathways, we describe multiple upregulated NF-κB signaling elements in human and murine schwannomas, leading us to identify a caspase-cleaved, proteasome-resistant NIK kinase domain fragment that amplifies pathogenic NF-κB signaling. Lentiviral-mediated transduction of this NIK fragment into normal SCs promotes proliferation, survival, and adhesion while inducing schwannoma formation in a novel in vivo orthotopic transplant model. Furthermore, we describe an NF-κB-potentiated hepatocyte growth factor (HGF) to MET proto-oncogene receptor tyrosine kinase (c-Met) autocrine feed-forward loop promoting SC proliferation. These innovative studies identify a novel signaling axis underlying schwannoma formation, revealing new and potentially druggable schwannoma vulnerabilities with future therapeutic potential.
Regulation of glycolysis by Pdk functions as a metabolic checkpoint for cell cycle quiescence in hematopoietic stem cells
(Elsevier, 2013-01-03) Takubo, Keiyo; Nagamatsu, Go; Kobayashi, Chiharu I.; Nakamura-Ishizu, Ayako; Kobayashi, Hiroshi; Ikeda, Eiji; Goda, Nobuhito; Rahimi, Yasmeen; Johnson, Randall S.; Soga, Tomoyoshi; Hirao, Atsushi; Suematsu, Makoto; Suda, Toshio; Biochemistry and Molecular Biology, School of Medicine
Defining the metabolic programs that underlie stem cell maintenance will be essential for developing strategies to manipulate stem cell capacity. Mammalian hematopoietic stem cells (HSCs) maintain cell cycle quiescence in a hypoxic microenvironment. It has been proposed that HSCs exhibit a distinct metabolic phenotype under these conditions. Here we directly investigated this idea using metabolomic analysis and found that HSCs generate adenosine-5'-triphosphate by anaerobic glycolysis through a pyruvate dehydrogenase kinase (Pdk)-dependent mechanism. Elevated Pdk expression leads to active suppression of the influx of glycolytic metabolites into mitochondria. Pdk overexpression in glycolysis-defective HSCs restored glycolysis, cell cycle quiescence, and stem cell capacity, while loss of both Pdk2 and Pdk4 attenuated HSC quiescence, glycolysis, and transplantation capacity. Moreover, treatment of HSCs with a Pdk mimetic promoted their survival and transplantation capacity. Thus, glycolytic metabolic status governed by Pdk acts as a cell cycle checkpoint that modulates HSC quiescence and function.
Role of eIF2α Kinases in Translational Control and Adaptation to Cellular Stress
(Cold Spring Harbor Laboratory Press, 2018-12-12) Wek, Ronald C.; Biochemistry and Molecular Biology, School of Medicine
A central mechanism regulating translation initiation in response to environmental stress involves phosphorylation of the α subunit of eukaryotic initiation factor 2 (eIF2α). Phosphorylation of eIF2α causes inhibition of global translation, which conserves energy and facilitates reprogramming of gene expression and signaling pathways that help to restore protein homeostasis. Coincident with repression of protein synthesis, many gene transcripts involved in the stress response are not affected or are even preferentially translated in response to increased eIF2α phosphorylation by mechanisms involving upstream open reading frames (uORFs). This review highlights the mechanisms regulating eIF2α kinases, the role that uORFs play in translational control, and the impact that alteration of eIF2α phosphorylation by gene mutations or small molecule inhibitors can have on health and disease.

Browsing by Subject "Protein-Serine-Threonine Kinases"

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