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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 955 records · Page 53
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Karyopherinβ1 regulates proliferation of human glioma cells via Wnt/β-catenin pathway

Karyopherinβ1 (KPNB1), one of the cytosolic factors involved in the selective protein transport across nucleus, docked at nuclear pore complex and transported through nuclear envelope in an ATP-dependent style, assisting proteins to be recognized as import substrates. It has been reported to be bound up with the origination and progress of lung cancer, cervical cancer, head and neck cancer and hepatocellular carcinoma. In current study, we demonstrated for the first time that the role of KPNB1 in human glioma. KPNB1 was over-expressed as the well-known trend of Ki-67(p < 0.01) and tightly closed to poor prognosis, as an independent prognostic factor. In vitro, up-regulation of KPNB1 was accompanied by certain rising levels of proliferation markers, employing U251 and U87MG cells as serum-starve models. Silencing KPNB1 in U251 and U87MG led to G1 phase arrested directly via flow cytometry analysis. In the nucleus of KPNB1-depletion cell models, the decreasing expression of KPNB1 and β-catenin was detected respectively, which indicated that KPNB1 functioned via β-catenin signal. Besides, the interaction between KPNB1 and β-catenin was proved clearly by immunoprecipitation. Taken together, it showed that KPNB1 might enhance human glioma proliferation via Wnt/β-Catenin Pathway. - Highlights: • KPNB1 accelerated the progress of human glioma via Wnt/β-catenin pathway. • The decreased β-catenin expression in nucleus of KPNB1-depletion cells. • We identified the interaction between β-catenin and KPNB1 for the first time. • The close positive relationship between KPNB1 expression and glioma proliferation. • Two kinds of glioma cell lines were applied to this study.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Structural basis for multi-specific peptide recognition by the anti-IDH1/2 monoclonal antibody, MsMab-1

A point mutation in isocitrate dehydrogenase 1 (IDH1) and IDH2 is directly linked to the pathogenesis of certain types of tumors. To detect this mutation, several antibodies that can distinguish between mutant and wild-type enzymes have been established. One of which, MsMab-1, has a unique multi-specific character against several types of mutated IDH1/2. This promiscuous character is in remarkable contrast to the highly specific antigen recognition typically observed with a monoclonal antibody. We solved the crystal structure of MsMab-1 Fab fragment in complex with either IDH1 or IDH2-derived peptides. Based on the structure, it became clear that the peptide-binding pocket of the antibody is highly complementary to the core determinant shared between the IDH1 and IDH2, while leaving just enough space for the side chain of the pathogenic but not the wild-type amino acids located in the mutation position. Clarification of the molecular basis for the peculiar binding characteristics of MsMab-1 in atomic detail will help facilitating its diagnostic application, and may be used to develop better diagnostic reagents through structure-guided protein engineering. - Highlights: • Mutations of IDH1 and IDH2 correlates with the pathogeny of a part of brain tumor. • A monoclonal antibody MsMab-1 recognizes several mutated sequences of IDH1 and IDH2. • MsMab-1 has high potential in diagnostic applications for brain tumors. • Crystal structures reveal the molecular basis of the multi-specificity of MsMab-1.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

NSrp70 is significant for embryonic growth and development, being a crucial factor for gastrulation and mesoderm induction

NSrp70 (nuclear speckle-related protein 70), a recently discovered protein and it belongs to the serine/arginine (SR) rich related protein family. NSrp70 is recognized as an important splicing factor comprising RNA recognition motif (RRM) and arginine/serine (RS)-like regions at the N- and C-terminus respectively, along with two coiled coil domains at each terminus. However, other functions of NSrp70 remain unelucidated. In this study, we investigated the role of NSrp70 in Xenopus embryogenesis and found that its maternal expression plays a critical role in embryonic development. Knockdown of NSrp70 resulted in dramatic reduction in the length of developing tadpoles and mild to severe malformation in Xenopus embryos. In addition, knockdown of NSrp70 resulted in an extremely short axis by blocking gastrulation and convergent extension. Further, animal cap assays along with activin A treatment revealed that NSrp70 is an essential factor for dorsal mesoderm induction as knockdown of NSrp70 caused a dramatic down-regulation of dorsal mesoderm specific genes and its loss significantly shortened the elongation region of animal caps. In conclusion, NSrp70 is crucial for early embryonic development, influencing gastrulation and mesoderm induction. - Highlights: • NSrp70 is required for proper length and dorso-anterior structures. • NSrp70 is essential for gastrulation movement during embryogenesis. • NSrp70 is crucial component for dorsal mesoderm induction.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Leptin promotes endothelial dysfunction in chronic kidney disease through AKT/GSK3β and β-catenin signals

Endothelial dysfunction (ED) is a well-recognized instigator of cardiovascular diseases and develops in chronic kidney disease (CKD) with high rate. Recent studies have implicated that leptin is associated with endothelial dysfunction. We investigated the relationship between leptin and markers of ED in CKD patients and how leptin contributed to endothelial damage. 140 CKD patients and 140 healthy subjects were studied. Serum leptin levels were significantly higher in CKD than in controls and displayed significantly positive association with the increase levels of sICAM-1 and sVCAM-1 but negative correlation with flow-mediated dilatation (FMD) reduction in patients. Our in vitro study demonstrated that leptin induced overexpression of ICAM-1 and VCAM-1, led to f-actin reorganization and vinculin assembly, increased endothelial monolayer permeability for FITC-dextran, and accelerated endothelial cell migration; these changes were markedly reversed when the cells were transfected with AKT or β-catenin shRNA vectors. Notably, high leptin resulted in hyper-phosphorylation of AKT and GSK3β, along with nuclear accumulation of β-catenin. In conclusion, serum leptin was elevated in CKD patients and it might contribute to endothelial dysfunction by disarrangement of f-actin cytoskeleton via a mechanism involving the AKT/GSK3β and β-catenin pathway. - Highlights: • Serum leptin was elevated in CKD patients and it was associated with endothelial dysfunction. • Leptin induced endothelial dysfunction by remodeling cytoskeleton in HUVECs. • Leptin promoted endothelial dysfunction via a mechanism involving the AKT/GSK3β and β-catenin signals.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Inhibition of FGF signaling accelerates neural crest cell differentiation of human pluripotent stem cells

Neural crest (NC) is a transient population, arising during embryonic development and capable of differentiating into various somatic cells. The defects of neural crest development leads to neurocristopathy. Several signaling pathways were revealed their significance in NC cell specification. Fibroblast growth factor (FGF) is recognized as an important signaling during NC development, for instance Xenopus and avian; however, its contributions in human species are remained elusive. Here we used human pluripotent stem cells (hPSCs) to investigate the consequences of FGF inhibition during NC cell differentiation. The specific-FGF receptor inhibitor, SU5402, was used in this investigation. The inhibition of FGF did not found to affect the proliferation or death of hPSC-derived NC cells, but promoted hPSCs to commit NC cell fate. NC-specific genes, including PAX3, SLUG, and TWIST1, were highly upregulated, while hPSC genes, such as OCT4, and E-CAD, rapidly reduced upon FGF signaling blockage. Noteworthy, TFAP-2α, a marker of migratory NC cells, abundantly presented in SU5402-induced cells. This accelerated NC cell differentiation could be due to the activation of Notch signaling upon the blockage of ERK1/2 phosphorylation, since NICD was increased by SU5402. Altogether, this study proposed the contributions of FGF signaling in controlling human NC cell differentiation from hPSCs, the crosstalk between FGF and Notch, and might imply to the influences of FGF signaling in neurocristophatic diseases.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

Negative regulation of NOD1 mediated angiogenesis by PPARγ-regulated miR-125a

Infection with pathogens activates the endothelial cell and its sustained activation may result in impaired endothelial function. Endothelial dysfunction contributes to the pathologic angiogenesis that is characteristic of infection-induced inflammatory pathway activation. Nucleotide-binding oligomerization domain-containing protein 1 (NOD1) is a protein receptor which recognizes bacterial molecules and stimulates an immune reaction in various cells; however, the underlying molecular mechanisms in the regulation of inflammation-triggered angiogenesis are not fully understood. Here we report that peroxisome proliferator-activated receptor gamma (PPARγ)-mediated miR-125a serves as an important regulator of NOD1 agonist-mediated angiogenesis in endothelial cells by directly targeting NOD1. Treatment of human umbilical vein endothelial cells with natural PPARγ ligand, 15-Deoxy-Delta12,14-prostaglandin J2, led to inhibition of NOD1 expression; contrarily, protein levels of NOD1 were significantly increased by PPARγ knockdown. We report that PPARγ regulation of NOD1 expression is a novel microRNA-mediated regulation in endothelial cells. MiR-125a expression was markedly decreased in human umbilical vein endothelial cells subjected to PPARγ knockdown while 15-Deoxy-Delta12,14-prostaglandin J2 treatment increased the level of miR-125a. In addition, NOD1 is closely regulated by miR-125a, which directly targets the 3′ untranslated region of NOD1. Moreover, both overexpression of miR-125a and PPARγ activation led to inhibition of NOD1 agonist-induced tube formation in endothelial cells. Finally, NOD1 agonist increased the formation of cranial and subintestinal vessel plexus in zebrafish, and this effect was abrogated by concurrent PPARγ activation. Overall, these findings identify a PPARγ-miR-125a-NOD1 signaling axis in endothelial cells that is critical in the regulation of inflammation-mediated angiogenesis. - Highlights: • Expression of NOD1 is regulated by PPARγ signaling in HUVECs. • PPARγ-regulated NOD1 expression is mediated at least in part by of miR-125a. • NOD1 is a novel target gene of miR-125. • miR-125a inhibits inflammation induced angiogenesis in HUVECs. • PPARγ activation inhibits inflammation mediated angiogenesis in vitro and in vivo.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

A human Fab exclusively binding to the extracellular domain of LMP2A

In the areas of North Africa, Southeast Asia as well as South China, Nasopharyngeal carcinoma (NPC) is among the most widespread cancers. Plenty of research findings confirmed that Epstein-Barr virus (EBV) played a crucial role in NPC. EBV-encoded Latent membrane protein 2A (LMP2A) which continuously expressed in cell membrane protein induced an epithelial-mesenchymal transition and increased the number of side population stem-like cancer cells in NPC. This reveals that LMP2A could contribute to the development and recurrence in NPC. Above evidences suggest that LMP2A could be the potential target molecule in the treatment of NPC. In the current study, a novel human antibody Fab (Fab29) against the extracellular domain of LMP2A was produced with success. Through immunofluorescence experiment it was proved that human antibody Fab29 exclusively combined the surface of SUNE cells (LMP2A-positive). Then flow cytometry result exhibited that the fluorescent intensities of SUNE cells and CNE cells were distinct (96.89% and 0.02% respectively). After that, it was shown by affinity test that the Fab29 fragment had high affinity (KD (M) 1.79E-09) with LMP2A. It was also revealed by immunohistochemical analysis that the Fab29 fragment could combine with LMP2A-positive human NPC tissues in comparison with the control group. Finally, the MTT result indicated that the Fab29 fragment could inhibit the proliferation of LMP2A-positive NPC cells. The inhibiting rate to SUNE cell proliferation reached a peak by Fab29 (19.67%) compared with unrelated Fab and CNE with Fab29 at a concentration of 500 μg/L in first 24 h and in the next 24 h the inhibition rate grew to 22.54%. In brief, it was shown that Fab29, a characteristic human antibody, could recognize LMP2A protein and inhibit the proliferation of LMP2A-expressing NPC cells in vitro.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

ALDH2 restores exhaustive exercise-induced mitochondrial dysfunction in skeletal muscle

Background: Mitochondrial aldehyde dehydrogenase 2 (ALDH2) is highly expressed in heart and skeletal muscles, and is the major enzyme that metabolizes acetaldehyde and toxic aldehydes. The cardioprotective effects of ALDH2 during cardiac ischemia/reperfusion injury have been recognized. However, less is known about the function of ALDH2 in skeletal muscle. This study was designed to evaluate the effect of ALDH2 on exhaustive exercise-induced skeletal muscle injury. Methods: We created transgenic mice expressing ALDH2 in skeletal muscles. Male wild-type C57/BL6 (WT) and ALDH2 transgenic mice (ALDH2-Tg), 8-weeks old, were challenged with exhaustive exercise for 1 week to induce skeletal muscle injury. Animals were sacrificed 24 h post-exercise and muscle tissue was excised. Results: ALDH2-Tg mice displayed significantly increased treadmill exercise capacity compared to WT mice. Exhaustive exercise caused an increase in mRNA levels of the muscle atrophy markers, Atrogin-1 and MuRF1, and reduced mitochondrial biogenesis and fusion in WT skeletal muscles; these effects were attenuated in ALDH2-Tg mice. Exhaustive exercise also enhanced mitochondrial autophagy pathway activity, including increased conversion of LC3-I to LC3-II and greater expression of Beclin1 and Bnip3; the effects of which were mitigated by ALDH2 overexpression. In addition, ALDH2-Tg reversed the increase of an oxidative stress biomarker (4-hydroxynonenal) and decreased levels of mitochondrial antioxidant proteins, including manganese superoxide dismutase and NAD(P)H:quinone oxidoreductase 1, in skeletal muscle induced by exhaustive exercise. Conclusion: ALDH2 may reverse skeletal muscle mitochondrial dysfunction due to exhaustive exercise by regulating mitochondria dynamic remodeling and enhancing the quality of mitochondria. - Highlights: • Skeletal muscle ALDH2 expression and activity declines during exhaustive exercise. • ALDH2 overexpression enhances physical performance and restores muscle atrophy. • ALDH2 overexpression attenuates exercise-induced mitochondrial oxidative stress.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

Discovery of a Kelch-like ECH-associated protein 1-inhibitory tetrapeptide and its structural characterization

Keap1 constitutively binds to the transcription factor Nrf2 to promote its degradation, resulting in negative modulation of genes involved in cellular protection against oxidative stress. Keap1 is increasingly recognized as an attractive target for treating diseases involving oxidative stress, including cancer, atherosclerosis, diabetes, arthritis, and neurodegeneration. We used phage-display peptide screening to identify a tetrapeptide showing moderate binding affinity, which inhibits the interaction between Nrf2 and Keap1. The tetrapeptide does not include an ETGE motif, which is a commonly found consensus sequence in known peptidic inhibitors. In addition to affinity parameters, IC{sub 50}, K{sub D}, and thermodynamic parameters, the crystal structure of the complex was determined to elucidate the binding conformation. The binding interactions resemble those of known small-molecule inhibitors as opposed to those of substrates and peptidic inhibitors. Although the tetrapeptide's affinity is not very high, our results may help facilitate the designing of small-molecule inhibitors during lead generation in drug discovery. - Highlights: • Keap1 inhibitory tetrapeptide with moderate affinity was discovered. • Crystal structure of the complex showed the unique binding mode. • Structural information gives a valuable insight for design of therapeutic compounds.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

Effects of naturally occurring charged mutations on the structure, stability, and binding of the Pin1 WW domain

Pin1 is a peptidyl-prolyl cis-trans isomerase, whose WW domain specifically recognizes the pSer/Thr-Pro motif. Pin1 is involved in multiple phosphorylation events that regulate the activities of various substrates, and Pin1 deregulation has been reported in various diseases, including cancer and Alzheimer's disease. The WW domain of Pin1 has been used as a small model protein to investigate the folding mechanisms of the β-sheet structure by studying the effect of mutations or its naturally occurring variants. However, only a few studies have investigated the structure and binding of Pin1 WW mutants. In the present work, two naturally occurring Pin1 WW variants, namely, G20D and S16R, derived from the cynomolgus monkey and African green monkey, respectively, were selected to investigate the influence of charge mutation on the structure, stability, and binding properties of the Pin1 WW domain. Analysis using a combination of nuclear magnetic resonance (NMR) and chemical shift-based calculations revealed that the G20D and S16R mutants had high structural similarity to the wild-type Pin1 WW domain. However, the presence of a charge mutation significantly decreased the stability of the Pin1 WW domain. Both the wild-type and G20D forms of the Pin1 WW domain utilized a three-site mode to bind to a phosphorylated Tau peptide, pT231, whereas the S16R mutant binds to the pT231 peptide either in a non-specific manner or through a totally different binding mechanism. Correspondingly, the wild-type and two mutant Pin1 WW domains showed different binding affinities to the Tau phosphopeptide. Considering that the WW domain participates in the catalytic activity of the Pin1 isomerase, our study represents a novel approach for studying Pin1 function through the analysis of its naturally occurring mutants. - Highlights: • G20D and S16R Pin1 WW had high structure similarity to wild-type. • Stabilities of G20D and S16R mutant Pin1 WW significantly decreased. • wild-type and G20D Pin1 WW utilized three-site mode for phosphorylated Tau binding. • wild-type and mutant Pin1 WW showed differential binding affinities to substrate.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

Th17 cell-mediated immune responses promote mast cell proliferation by triggering stem cell factor in keratinocytes

Although mast cells are traditionally thought to function as effector cells in allergic responses, they have increasingly been recognized as important regulators of various immune responses. Mast cells mature locally; thus, tissue-specific influences are important for promoting mast cell accumulation and survival in the skin and the gastrointestinal tract. In this study, we determined the effects of keratinocytes on mast cell accumulation during Th17-mediated skin inflammation. We observed increases in dermal mast cells in imiquimod-induced psoriatic dermatitis in mice accompanied by the expression of epidermal stem cell factor (SCF), a critical mast cell growth factor. Similar to mouse epidermal keratinocytes, SCF was highly expressed in the human HaCaT keratinocyte cell line following stimulation with IL−17. Further, keratinocytes promoted mast cell proliferation following stimulation with IL−17 in vitro. However, the effects of keratinocytes on mast cells were significantly diminished in the presence of anti−CD117 (stem cell factor receptor) blocking antibodies. Taken together, our results revealed that the Th17-mediated inflammatory environment promotes mast cell accumulation through keratinocyte-derived SCF. - Highlights: • Psoriasis-like skin inflammation increase dermal mast cells. • Keratinocyte produce stem cell factor in psoriasis-like skin inflammation. • Keratinocyte promote mast cell proliferation by stem cell factor dependent manner.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

Highly efficient one-step scarless protein tagging by type IIS restriction endonuclease-mediated precision cloning

Protein tagging with a wide variety of epitopes and/or fusion partners is used routinely to dissect protein function molecularly. Frequently, the required DNA subcloning is inefficient, especially in cases where multiple constructs are desired for a given protein with unique tags. Additionally, the generated clones have unwanted junction sequences introduced. To add versatile tags into the extracellular domain of the transmembrane protein THSD1, we developed a protein tagging technique that utilizes non-classical type IIS restriction enzymes that recognize non-palindromic DNA sequences and cleave outside of their recognition sites. Our results demonstrate that this method is highly efficient and can precisely fuse any tag into any position of a protein in a scarless manner. Moreover, this method is cost-efficient and adaptable because it uses commercially available type IIS restriction enzymes and is compatible with the traditional cloning system used by many labs. Therefore, precision tagging technology will benefit a number of researchers by providing an alternate method to integrate an array of tags into protein expression constructs.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Spatiotemporal control of mitochondrial network dynamics in astroglial cells

Highlights: • Astrocytes display highly complex mitochondrial architectures in vivo. • Mitochondrial trafficking and dynamics in astrocytes are regulated. • Mitochondria critically contribute to astrocyte Ca{sup 2+} handling. • Astrocyte reacting to injury undergo marked changes in mitochondrial dynamics. Mitochondria are increasingly recognized for playing important roles in regulating the evolving metabolic state of mammalian cells. This is particularly true for nerve cells, as dysregulation of mitochondrial dynamics is invariably associated with a number of neuropathies. Accumulating evidence now reveals that changes in mitochondrial dynamics and structure may play equally important roles also in the cell biology of astroglial cells. Astroglial cells display significant heterogeneity in their morphology and specialized functions across different brain regions, however besides fundamental differences they seem to share a surprisingly complex meshwork of mitochondria, which is highly suggestive of tightly regulated mechanisms that contribute to maintain this unique architecture. Here, we summarize recent work performed in astrocytes in situ indicating that this may indeed be the case, with astrocytic mitochondrial networks shown to experience rapid dynamic changes in response to defined external cues. Although the mechanisms underlying this degree of mitochondrial re-shaping are far from being understood, recent data suggest that they may contribute to demarcate astrocyte territories undergoing key signalling and metabolic functions.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

The regulation of tumor cell physiology by mitochondrial dynamics

Highlights: • Mitochondrial fusion and fission can influence mitochondrial function. • Mitochondrial function underlies a number of physiological changes associated with cancer. • Mitochondrial dynamics represent a potential mechanism cancer cells use to promote tumorigenic growth. Mitochondrial dynamics are increasingly recognized to play an important role in regulating mitochondrial function in response to diverse stimuli. Given the overlap in the physiological processes influenced by mitochondria and the physiological processes disrupted in tumor cells, we speculate that tumor cells alter mitochondrial shape to promote the tumorigenic phenotype. Here, we briefly review the evidence linking changes in mitochondrial fusion and fission to a number of key tumorigenic processes, including metabolic rewiring, inhibition of cell death, cell migration, cell proliferation and self-renewal capacity. The role of mitochondrial dynamics in tumor growth is an important emerging area of research, a better understanding of which may lead to promising new therapeutic options for the treatment of cancer.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

Structure insights into the molecular mechanism of the interaction between UHRF2 and PCNA

Highlights: • UHRF2 interacts with PCNA through its PIP box. • Complex structure of PCNA/UHRF2{sup PIP} reveals the molecular mechanism of how PCNA recognizes UHRF2. • UHRF2-PIP box interacts with PCNA mainly via hydrophobic interaction. • The hydrogen bond formed between PCNA-H44 and UHRF2{sup PIP}-D792 is critical for the interaction. UHRF2 (Ubiquitin-like with PHD and ring finger domains 2) is an E3 ubiquitin ligase that plays important roles in DNA methylation, histone modifications and cell cycle regulation by interacting with multiple epigenetic or cell-cycle related proteins. Previous studied have identified PCNA (Proliferating cell nuclear antigen) as an interacting partner of UHRF2 by using the antibody microarray. However, the molecular mechanism and the function of UHRF2-PCNA interaction remains unclear. Here, we report the complex structure of PCNA and the peptide ({sup 784}NEILQTLLDLFFPGYSK{sup 800}) derived from UHRF2 that contains a PIP box. Structural analysis combined with mutagenesis experiments provide the molecular basis for the recognition of UHRF2 by PCNA via PIP-box.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Identification of a selective inhibitor of human monocarboxylate transporter 4

Highlights: • hMCT4 transporter mediates the transport of metabolites such as l-lactate and pyruvate. • 5-ETZ, a bioisostere of propionate, is recognized by hMCT1 and hMCT4. • Fibrates, a group of isobutyrate derivatives, selectively inhibit hMCT4. • Bindarit might be the first-identified potent and selective inhibitor of hMCT4. The human monocarboxylate transporters (hMCTs/SLC16As) mediate the uptake of various monocarboxylates. Several isoforms of hMCTs are expressed in cancerous tissue as well as in normal tissue. In cancerous tissue, hypoxia induces the expression of hMCT4, which transports the energetic metabolite l-lactate across the plasma membrane. Since hMCT4 is involved in pH regulation and the transport of l-lactate in cancer cells, an hMCT4 inhibitor could function as an anticancer agent. Although several non specific hMCT inhibitors have been developed, a selective hMCT4 inhibitor has not yet been identified. The aim of this study was therefore to identify a selective hMCT4 inhibitor for use as a pharmacological tool for studying hMCT4. The heterologous expression system of the Xenopus oocyte was used to assess the effects of test compounds on hMCT4, whereupon isobutyrate derivatives, fibrates, and bindarit (2-[(1-benzyl-1H-indazol-3-yl)methoxy]-2-methylpropanoic acid) were demonstrated to exhibit selective inhibitory effects against this transporter. It is suggested that the structure formed from the joining of an isobutyrate moiety and two aromatic rings by appropriate linkers is important for acquiring the selective hMCT4-inhibiting activity. These findings provide novel insights into the ligand recognition of hMCT4, and contribute to the development of novel anticancer agents.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

Building kit for metal cation binding sites in proteins

Starting with conformations of calcium-binding sites in parvalbumin and integrin (representative structures of EF-hand and calcium blade zones, respectively) we introduce four new different local Ca{sup 2+}-recognition units in proteins: a one-residue unit type I (ORI); a three-residue unit type I (TRI); a one-residue unit type II (ORII) and a three-residue unit type II (TRII). Based on the amount and nature of variable atoms, the type I and II units theoretically can have four and twelve variants, respectively. Analysis of known “Ca{sup 2+}-bound functional niches” in proteins revealed presence of almost all possible variants of Ca{sup 2+}-recognition units in actual structures. Parvalbumin, integrin alpha-IIb and sixteen other proteins with different Ca{sup 2+}-bound functional niches contain various consecutively joined combinations of OR(I/II) and TR(I/II) units. Such a OR(I/II)+TR(I/II) joint unit forms a tripeptide, which uses three main-chain atoms for metal binding: nitrogen{sub n} (Donor), oxygen{sub n} (Acceptor) and nitrogen{sub n+2} (Donor). Thus, taken together, the described ORI, TRI, ORII and TRII units can serve as elementary blocks to construct more complex calcium recognizing substructures in a variety of calcium binding sites of unrelated proteins.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

Sez6l2 regulates phosphorylation of ADD and neuritogenesis

Highlights: • Sez6l2 interacts with ADD and GluR1. • Extracellular domains of Sez6l2 and GluR1 are required for their interactions. • Sez6l2 may be one of the auxiliary subunits with AMPA receptors. • Sez6l2 may link GluR1 to ADD and be an up-regulator of ADD phosphorylation. Increasing evidence shows that immune-mediated mechanisms may contribute to the pathogenesis of central nervous system disorders including cerebellar ataxias, as indicated by the aberrant production of neuronal surface antibodies. We previously reported a patient with cerebellar ataxia associated with production of a new anti-neuronal antibody, anti-seizure-related 6 homolog like 2 (Sez6l2). Sez6l2 is a type 1 membrane protein that is highly expressed in the hippocampus and cerebellar cortex and mice lacking Sez6l2 protein family members develop ataxia. Here we used a proteomics-based approach to show that serum derived from this patient recognizes the extracellular domain of Sez6l2 and that Sez6l2 protein binds to both adducin (ADD) and glutamate receptor 1 (GluR1). Our results indicate that Sez6l2 is one of the auxiliary subunits of the AMPA receptor and acts as a scaffolding protein to link GluR1 to ADD. Furthermore, Sez6l2 overexpression upregulates ADD phosphorylation, whereas siRNA-mediated downregulation of Sez612 prevents ADD phosphorylation, suggesting that Sez6l2 modulates AMPA-ADD signal transduction.

60 APPLIED LIFE SCIENCES↗