scholarly journals Structural and Functional Characterization of SARS-CoV-2 RBD Domains Produced in Mammalian Cells

2021 ◽  
Author(s):  
Christoph Gstöttner ◽  
Tao Zhang ◽  
Anja Resemann ◽  
Sophia Ruben ◽  
Stuart Pengelley ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Functional Characterization

Identification and functional characterization of a novel human protein highly related to the yeast dynamin-like GTPase Vps1p

1998 ◽  
Vol 111 (10) ◽  
pp. 1341-1349 ◽  
Author(s):  
M. Imoto ◽  
I. Tachibana ◽  
R. Urrutia
Keyword(s):  
Endoplasmic Reticulum ◽  
Cho Cells ◽  
Mammalian Cells ◽  
Functional Characterization ◽  
Luciferase Reporter ◽  
Pleckstrin Homology ◽  
Rich Region ◽  
Gtpase Domain ◽  
Proline Rich Region

Dynamin proteins containing a GTPase domain, a pleckstrin homology motif and a proline-rich tail participate in receptor-mediated endocytosis in organisms ranging from insects to vertebrates. In addition, dynamin-related GTPases, such as the yeast Golgi protein Vps1p, which lack both the pleckstrin homology motif and the proline-rich region, participate in vesicular transport within the secretory pathway in lower eukaryotes. However, no data is available on the existence of Vps1p-like proteins in mammalian cells. In this study, we report the identification and characterization of a novel gene encoding a human dynamin-related protein, DRP1, displaying high similarity to the Golgi dynamin-like protein Vps1p from yeast and to a Caenorhabditis elegans protein deposited in the databank. These proteins are highly conserved in their N-terminal tripartite GTPase domain but lack the pleckstrin homology motif and proline-rich region. Northern blot analysis reveals that the DRP1 mRNA is detected at high levels in human muscle, heart, kidney and brain. Immunolocalization studies in Chinese hamster ovary (CHO) cells using an epitope-tagged form of DRP1 and confocal microscopy show that this protein is concentrated in a perinuclear region that labels with the endoplasmic reticulum marker DiOC6(3) and the Golgi marker C5-DMB-Cer. In addition, the localization of DRP1 is highly similar to the localization of the endoplasmic reticulum and cis-Golgi GTPase Rab1A, but not to the staining for the trans-Golgi GTPase Rab6. Furthermore, overexpression of a cDNA encoding a GTP binding site mutant of DRP1 (DRP1(K38E)) in CHO cells decreases the amount of a secreted luciferase reporter protein, whereas the overexpression of wild-type DRP1 increases the secretion of this marker. Together, these results constitute the first structural and functional characterization of a mammalian protein similar to the yeast dynamin-related GTPase Vps1p and indicate that the participation of these proteins in secretion has been conserved throughout evolution.

scholarly journals Functional characterization of ecdysone receptor gene switches in mammalian cells

FEBS Journal ◽  
2006 ◽  
Vol 273 (24) ◽  
pp. 5550-5563 ◽  
Author(s):  
Siva K. Panguluri ◽  
Prasanna Kumar ◽  
Subba R. Palli
Keyword(s):  
Mammalian Cells ◽  
Receptor Gene ◽  
Functional Characterization ◽  
Ecdysone Receptor ◽  
Gene Switches

scholarly journals Genetic and functional characterization of putative Ras/Raf interaction inhibitors in C. elegans and mammalian cells

2010 ◽  
Vol 5 ◽  
pp. 2 ◽  
Author(s):  
Vanessa González-Pérez ◽  
David J Reiner ◽  
Jamie K Alan ◽  
Cicely Mitchell ◽  
Lloyd J Edwards ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Functional Characterization ◽  
C Elegans

scholarly journals Characterization of small-molecule inhibitors of the sodium iodide symporter

2008 ◽  
Vol 200 (3) ◽  
pp. 357-365 ◽  
Author(s):  
Sabine Lindenthal ◽  
Nathalie Lecat-Guillet ◽  
Alejandro Ondo-Mendez ◽  
Yves Ambroise ◽  
Bernard Rousseau ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Sodium Iodide ◽  
Functional Characterization ◽  
Screening Method ◽  
Inhibitory Effect ◽  
Independent Effect ◽  
Induced Current ◽  
Sodium Iodide Symporter ◽  
Iodide Uptake

The sodium/iodide symporter (NIS) mediates the active transport of iodide from the bloodstream into thyrocytes. NIS function is strategic for the diagnosis and treatment of various thyroid diseases. In addition, a promising anti-cancer strategy based on targeted NIS gene transfer in non-thyroidal cells is currently developed. However, only little information is available concerning the molecular mechanism of NIS-mediated iodide translocation. Ten small molecules have recently been identified using a high-throughput screening method for their inhibitory effect on iodide uptake of NIS-expressing mammalian cells. In the present study, we analyzed these compounds for their rapid and reversible effects on the iodide-induced current in NIS-expressing Xenopus oocytes. Four molecules almost completely inhibited the iodide-induced current; for three of them the effect was irreversible, for one compound the initial current could be fully re-established after washout. Three molecules showed a rapid inhibitory effect of about 75%, half of which was reversible. Another three compounds inhibited the iodide-induced current from 10 to 50%. Some molecules altered the membrane conductance by themselves, i.e. in the absence of iodide. For one of these molecules the observed effect was also found in water-injected oocytes whereas for some others the iodide-independent effect was associated with NIS expression. The tested molecules show a surprisingly high variability in their possible mode of action, and thus are promising tools for further functional characterization of NIS on a molecular level, and they could be useful for medical applications.

scholarly journals Functional Characterization of the Atypical Integral Membrane Lipid Phosphatase PDP1/PPAPDC2 Identifies a Pathway for Interconversion of Isoprenols and Isoprenoid Phosphates in Mammalian Cells

2010 ◽  
Vol 285 (18) ◽  
pp. 13918-13929 ◽  
Author(s):  
Sumitra Miriyala ◽  
Thangaiah Subramanian ◽  
Manikandan Panchatcharam ◽  
Hongmei Ren ◽  
Mark I. McDermott ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Functional Characterization ◽  
Membrane Lipid ◽  
Lipid Phosphatase

Functional Characterization of Insulation Effect for Synthetic Gene Circuits in Mammalian Cells

2018 ◽  
Vol 7 (2) ◽  
pp. 412-418 ◽  
Author(s):  
Weixi Liao ◽  
Bing Liu ◽  
Chih-Chun Chang ◽  
Ling-Jun Lin ◽  
Che Lin ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Functional Characterization ◽  
Synthetic Gene ◽  
Gene Circuits ◽  
Synthetic Gene Circuits ◽  
Insulation Effect

scholarly journals Characterization of Na+/H+ exchanger NHE8 in cultured renal epithelial cells

2007 ◽  
Vol 293 (3) ◽  
pp. F761-F766 ◽  
Author(s):  
Jianning Zhang ◽  
Ion Alexandru Bobulescu ◽  
Sunita Goyal ◽  
Peter S. Aronson ◽  
Michel G. Baum ◽  
...  
Keyword(s):  
Protein Expression ◽  
Mammalian Cells ◽  
Small Interfering Rna ◽  
Apical Membrane ◽  
Basolateral Membrane ◽  
Functional Characterization ◽  
Protein Levels ◽  
Primary Amino ◽  
Interfering Rna

NHE8 is expressed in the apical membrane of the proximal tubule and is predicted to be a Na+/H+ exchanger on the basis of its primary amino acid sequence. Functional characterization of native NHE8 in mammalian cells has not been possible to date. We screened a number of polarized renal cell lines for the plasma membrane Na+/H+ exchangers (NHE1, 2, 3, 4, and 8) and found only NHE1 and NHE8 transcripts in NRK cells by RT-PCR. NHE8 protein is expressed in the apical membrane of NRK cells as demonstrated by immunoblots, confocal fluorescent immunocytochemistry, and immunoelectron microscopy. NHE1, on the other hand, is expressed primarily in the basolateral membrane. Bilateral perfusion of NRK cells grown on permeable supports shows Na+/H+ exchange activity on both the apical and basolateral membranes. NHE8-specific small interfering RNA knocks down NHE8 protein expression but does not affect NHE1 protein levels. Knockdown of NHE8 protein is accompanied by a commensurate reduction in apical NHE activity, without altered basolateral NHE activity. Conversely, transfection of NHE1-specific small interfering RNA knocks down NHE1 protein expression without affecting NHE8 protein levels and reduces basolateral NHE activity without affecting apical NHE activity. NHE8 is the only apical membrane Na+/H+ exchanger in NRK cells. NHE8 activity is Na+ dependent, displaying a cooperative sigmoidal relationship, and is highly sensitive to 5-( N-ethyl- n-isopropyl)-amiloride (EIPA). NRK cells provide a useful system where NHE8 can be studied in its native environment.

scholarly journals Yeast Cell-Based Transport Assay for the Functional Characterization of Human 4F2hc-LAT1 and ‐LAT2, and LAT1 and LAT2 Substrates and Inhibitors

2021 ◽  
Vol 8 ◽  
Author(s):  
Satish Kantipudi ◽  
Dimitrios Fotiadis
Keyword(s):  
Amino Acid ◽  
Mammalian Cells ◽  
Functional Characterization ◽  
Methylotrophic Yeast ◽  
Cell Types ◽  
Amino Acid Transporters ◽  
Cell Assays ◽  
Transport Assay ◽  
Compound Screening

In mammalian cells, the L-type amino acid transporters (LATs) LAT1 (SLC7A5) and LAT2 (SLC7A8) form heterodimeric amino acid transporters (HATs) with the ancillary protein 4F2hc and are involved in the cellular uptake of specific amino acids. The HAT 4F2hc-LAT1 is found upregulated in various cancer cell types, while 4F2hc-LAT2 is a transporter for non-cancer cells. Preclinical studies have highlighted that 4F2hc-LAT1 plays an important role in tumor progression representing a valid anticancer target. Consequently, current research is focusing on the development of potent and specific human 4F2hc-LAT1 inhibitors. On the other hand, 4F2hc-LAT2 is emerging as target of other diseases, thus also gaining clinical interest. To determine affinity and specificity of substrates and inhibitors for 4F2hc-LAT1 or 4F2hc-LAT2, robust transport cell assays are indispensable. We have optimized and validated a transport assay using cells of the methylotrophic yeast Pichia pastoris stably overexpressing the human HATs 4F2hc-LAT1 or -LAT2, and the LATs LAT1 or LAT2 alone. The radioligand [3H]L-leucine was used as reporter and the substrates L-leucine, triiodothyronine (T3) and thyroxine (T4) as well as the inhibitors BCH and JPH203 (KYT-0353) for assay validation. Obtained half-maximal inhibitory concentrations also provided new insights, e.g., into the LAT specificity of the potent inhibitor JPH203 and on the potency of the thyroid hormones T3 and T4 to inhibit transport through human 4F2hc-LAT2. The LAT1 and LAT2 assays are of particular interest to determine possible implications and influences of 4F2hc in ligand binding and transport. In summary, the presented assays are valuable for characterization of ligands, e.g., towards 4F2hc-LAT1 specificity, and can also be applied for compound screening. Finally, our established approach and assay would also be applicable to other HATs and LATs of interest.

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