Up-regulation of Sodium-dependent Glucose Transporter by Interaction with Heat Shock Protein 70

Ikari, Akira; Nakano, Mika; Kawano, Kazuya; Suketa, Yasunobu

doi:10.1074/jbc.m200310200

Cited by 46 publications

(28 citation statements)

References 28 publications

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“…Preparation of Membrane Fraction and ImmunoprecipitationWhole membrane fraction was prepared from MDCK cells on day 7 in culture as described previously (10). The samples were solubilized in a lysis buffer containing 1% Triton X-100, 150 mM NaCl, 0.5 mM EDTA, and 50 mM Tris-HCl (pH 8.0) and incubated with protein G-Sepharose beads and an antibody specific for GST at 4°C for 1 h with gentle rocking.…”

Section: Methodsmentioning

confidence: 99%

Association of Paracellin-1 with ZO-1 Augments the Reabsorption of Divalent Cations in Renal Epithelial Cells

Ikari

Hirai

Shiroma

et al. 2004

Journal of Biological Chemistry

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Paracellin-1 (PCLN-1) belongs to the claudin family of tight junction proteins and possibly plays a critical role in the reabsorption of magnesium and calcium. So far, the physiological properties of PCLN-1 have not been clarified. In the present study, we investigated whether PCLN-1 is associated with ZO-1. We also investigated whether 45 Ca 2؉ transport across the paracellular barrier is affected by this association. In vitro binding analysis using glutathione S-transferase fusion protein showed that the C-terminal TRV sequence, especially Thr and Val residues, of PCLN-1 interacts with ZO-1. Next, PCLN-1 was stably expressed in Madin-Darby canine kidney cells using a FLAG tagging vector. ZO-1 was co-immunoprecipitated with the wild-type PCLN-1 and the alanine substitution (TAV) mutant. However, mutants of the deletion (⌬TRV) and the alanine substitution (ARV and TRA) inhibited the association of PCLN-1 with ZO-1. Confocal immunofluorescence demonstrated that the wild-type PCLN-1 and the TAV mutant localized in the tight junction along with ZO-1, but the ⌬TRV, ARV, and TRA mutants were widely distributed in the lateral membrane including the tight junction area. Interestingly, monolayers of cells expressing the wild-type PCLN-1 and the TAV mutant showed higher activities of 45 Ca 2؉ transport from apical to basal compartments, compared with those expressing the ⌬TRV, ARV, and TRA mutants and the mock cells. 45 Ca 2؉ transport was inhibited by increased magnesium concentration suggesting that magnesium and calcium were competitively transported by PCLN-1. It was noted that a positive electrical potential gradient enhanced 45 Ca 2؉ transport from apical to basal compartments without affecting the opposite direction of transport. Thus, PCLN-1 localizes to the tight junction followed by association with ZO-1, and the PCLN-1⅐ZO-1 complex may play an essential role in the reabsorption of divalent cations in renal epithelial cells.

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Section: Methodsmentioning

confidence: 99%

Association of Paracellin-1 with ZO-1 Augments the Reabsorption of Divalent Cations in Renal Epithelial Cells

Ikari

Hirai

Shiroma

et al. 2004

Journal of Biological Chemistry

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“…The ability of cells to transport glucose has been linked to the capacity of cells to respond and survive deleterious cellular conditions (42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52)(53)(54)(55)(56). In many studies, blocking both glycolysis (48,51,57) and the hexosamine biosynthetic pathway (58 -61) results in decreased survival of cells.…”

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confidence: 99%

Dynamic O-GlcNAc Modification of Nucleocytoplasmic Proteins in Response to Stress

Zachara

O'Donnell

Cheung

et al. 2004

Journal of Biological Chemistry

525

499

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. O-GlcNAc is thought to act as a modulator of protein function, in a manner analogous to protein phosphorylation; the addition of O-GlcNAc to the protein backbone is dynamic and responds to morphogens, the cell cycle, and changes in glucose metabolism (1). The mechanisms by which O-GlcNAc act are complex, and changes in O-GlcNAc levels have been shown to alter the behavior of specific proteins by modulating the following: 1) the half-life and proteolytic processing of proteins (2-7); 2) subcellular localization (8 -14); 3) protein-protein interactions (6, 15, 16); 4) DNA binding (17); and 5) enzyme activity or regulation (18 -20). One mechanism by which O-GlcNAc may mediate these events is by altering protein phosphorylation. Notably, phosphorylation and O-GlcNAc are reciprocal on some well studied proteins, which include the C-terminal domain of the large subunit of RNA polymerase (21, 22), the c-myc protooncogene (23-25), SV40 large T-antigen (26), estrogen receptor-␤ (7), and endothelial nitric-oxide synthase (18). These observations suggest that O-GlcNAc and phosphorylation may modulate each other (27-29).Increasing extracellular glucose concentrations affects the functioning of key cellular proteins in an O-GlcNAc-dependent manner, including endothelial nitric-oxide synthase (18), mSin3a (30), the transcription factors, YY1 (31), Sp1 (5, 32-34), CREB (35), and the 26 S proteosomal complex (36, 37). UDPGlcNAc:polypeptide O-␤-N-acetylglucosaminyltransferase (OGT; EC 2.4.1.94), the enzyme that adds O-GlcNAc, is responsive across the physiological range of UDP-GlcNAc. Moreover, the substrate specificity of OGT changes at different UDPGlcNAc concentrations (38). Both in vitro and in vivo data support a model where increased UDP-GlcNAc levels, due to hyperglycemia, result in increased O-GlcNAc levels, leading to insulin resistance, a hallmark of type II diabetes (1, 39). These data and others have led researchers to propose that O-GlcNAc is a nutritional sensor (1, 39 -41).In response to multiple forms of stress, cells rapidly increase glucose uptake. The ability of cells to transport glucose has been linked to the capacity of cells to respond and survive deleterious cellular conditions (42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52)(53)(54)(55)(56). In many studies, blocking both glycolysis (48,51,57) and the hexosamine biosynthetic pathway (58 -61) results in decreased survival of cells. In some instances, alternative energy sources have been provided suggesting that depletion of ATP levels does NOT explain the decrease in survival (48,51,57). Several insulin-resistant models, including the long lived Caenorhabditis elegans Daf-2 knockout, have an increased stress tolerance to a variety of agents (62)(63)(64). Based upon these data, and recent observations suggesting that heat shock protein (HSP) 70 may act as an O-GlcNAc lectin (65), we investigated the possible link between stress tolerance and O-GlcNAc. We demonstrate that in response to all forms of cellular stress tested, multiple cell lines

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“…Our group has developed a neonatal piglet model that displays several similarities to the human infant, including alterations in response to hypoxia, such as changes in glutamate (28) or glucose transporters (29), and stress-related neurologic outcome (2). The aim of the present study was to determine the effect of birth hypoxia on stress proteins in the cerebellum, the cortex, and the hippocampus of piglets.…”

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Effects of Hypoxia on Stress Proteins in the Piglet Brain at Birth

et al. 2004

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Newborn piglets were submitted to normobaric hypoxia (5% O 2 , 95% N 2 ) for either 1 or 4 h. The effects of hypoxia on the neonatal brain were characterized through a time-course analysis of levels of various proteins such as heat shock proteins (HSP27, 70, and 90), hypoxia inducible factor-1␣ (HIF-1␣), neuronal nitric oxide synthase (nNOS), hemeoxygenase-2 (HO-2), and caspase-3. The expression of these proteins was determined at different stages of recovery up to 72 h in cerebellum, cortex, and hippocampus by Western blot analysis in hypoxic maintained animals that were made hypoxic at either 20 or 37°C. In all regions of the brain, HIF-1␣ and HSP27 expression were strongly increased until 22 h of recovery. No significant changes were observed for HSP70, HSP90, and HO-2. A small elevation of expression of nNOS was observed at early stages in the cerebellum and the cortex with no change in the hippocampus.Expression of caspase 3 was strongly increased in the cortex 24 and 48 h after hypoxia but unchanged in the hippocampus. These results are presented in terms of the porcine model of nonischemic hypoxia and its delayed neuronal effects on the cerebral outcome. Because of their recently established biochemical and functional interactions, the expression of the main HSPs, HIF-1␣, nNOS, and caspase-3 after hypoxia are delineated. Perinatal asphyxia and hypoxia are common causes of neonatal morbidity. Among survivors, several disabilities are observed, including pulmonary, renal, cardiac, and encephalopathic dysfunction (1,2). Asphyxia at birth can result in severe auditory problems for the infant (3,4) as well as increased risks of amnesia (5) and schizophrenia presenting at different stages (6). Outcomes of asphyxia and/or hypoxia-ischemia can also result in cognitive impairment and developmental delay for the infants (7). Such severe sequelae of birth hypoxia are apparent early at the molecular level in the brain. Impairment as a result of hypoxia includes the transient reduction of GABA receptor numbers (8), altered expression of glutamate transporters (9), and/or a disruption of myelin gene expression (10). Because of the severe consequences of hypoxia at birth time on cerebral functions, a better characterization of molecular changes within the hypoxic neonatal brain is of crucial importance.The study of the expression and induction of stress proteins in the hypoxic brain is of particular interest because heat shock proteins (HSPs) have cytoprotective properties and are induced after a variety of stressors, such as elevated temperature (11-13) or hypoxia (14). HSPs are classified in three large families according to their molecular weights (11-13). However, very few studies have described the developmental changes of HSPs at the time of birth (15-17). The protective role of HSPs against hypoxia at birth has not been investigated, although in the brain, these proteins are known to be cytoprotective after hypoxia-ischemia (18,19). Other proteins induced by neonatal hypoxic stress are also of interest. Hypoxia i...

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Up-regulation of Sodium-dependent Glucose Transporter by Interaction with Heat Shock Protein 70

Cited by 46 publications

References 28 publications

Association of Paracellin-1 with ZO-1 Augments the Reabsorption of Divalent Cations in Renal Epithelial Cells

Association of Paracellin-1 with ZO-1 Augments the Reabsorption of Divalent Cations in Renal Epithelial Cells

Dynamic O-GlcNAc Modification of Nucleocytoplasmic Proteins in Response to Stress

Effects of Hypoxia on Stress Proteins in the Piglet Brain at Birth

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