Priyadarshini M.,Northwestern University |
Villa S.R.,Northwestern University |
Fuller M.,Northwestern University |
Wicksteed B.,University of Chicago |
And 8 more authors.
Molecular Endocrinology | Year: 2015
G protein-coupled receptors have been well described to contribute to the regulation of glucosestimulated insulin secretion (GSIS). The short-chain fatty acid-sensing G protein-coupled receptor, free fatty acid receptor 2 (FFAR2), is expressed in pancreatic β-cells, and in rodents, its expression is altered during insulin resistance. Thus, we explored the role of FFAR2 in regulating GSIS. First, assessing the phenotype of wild-type and Ffar2(Formula presented) mice in vivo, we observed no differences with regard to glucose homeostasis on normal or high-fat diet, with a marginally significant defect in insulin secretion in Ffar2(Formula presented) mice during hyperglycemic clamps. In ex vivo insulin secretion studies, we observed diminished GSIS from Ffar2(Formula presented) islets relative to wild-type islets under high-glucose conditions. Further, in the presence of acetate, the primary endogenous ligand for FFAR2, we observed FFAR2-dependent potentiation of GSIS, whereas FFAR2-specific agonists resulted in either potentiation or inhibition of GSIS, which we found to result from selective signaling through either Gα9/11 or Gαi/o, respectively. Lastly, in ex vivo insulin secretion studies of human islets, we observed that acetate and FFAR2 agonists elicited different signaling properties at human FFAR2 than at mouse FFAR 2. Taken together, our studies reveal that FFAR2 signaling occurs by divergent G protein pathways that can selectively potentiate or inhibit GSIS in mouse islets. Further, we have identified important differences in the response of mouse and human FFAR2 to selective agonists, and we suggest that these differences warrant consideration in the continued investigation of FFAR2 as a novel type 2 diabetes target. (Molecular Endocrinology 29: 1055–1066, 2015) © 2015 by the Endocrine Society.
Wong R.G.,University of Southern California |
Wong R.G.,University of California at Los Angeles |
Kazane K.,Multispan |
Kazane K.,University of California at Los Angeles |
And 4 more authors.
Mitochondrion | Year: 2015
We studied the intramitochondrial localization of several multiprotein complexes involved in U-insertion/deletion RNA editing in trypanosome mitochondria. The editing complexes are located in one or two antipodal nodes adjacent to the kinetoplast DNA (kDNA) disk, which are distinct from but associated with the minicircle catenation nodes. In some cases the proteins are in a bilateral sheet configuration. We also found that mitoribosomes have a nodal configuration. This type of organization is consistent with evidence for protein and RNA interactions of multiple editing complexes to form an ~. 40S editosome and also an interaction of editosomes with mitochondrial ribosomes. © 2015 Elsevier B.V. and Mitochondria Research Society.
Multispan | Date: 2012-05-14
The present invention provides expression vectors that facilitate high levels of expression of GPCR proteins. Encompassed by the invention are methods and compositions for recombinant cell lines expressing GPCR proteins with the aid of the expression vectors of the instant invention. The recombinant cell lines of the instant invention express GPCR proteins at levels of at least about 150,000 copies of the protein per cell. The present invention also provides methods and compositions for raising antibodies against GPCR proteins using the high expressing recombinant cells of the instant invention.
GPCR Expression Technology Multispan uses a proprietary technology to enable expression of GPCR proteins in mammalian cells at over a million molecule per cell surface. High expressing cells (HExTM) can be developed into single cell clones and be used as unique source of high quality GPCR proteins for variety of applications, including: Antibody generation using antigens with natural epitopes at high expression level Cell-based or membrane receptor binding assays to achieve high signal-to-noise ratio Cell-based functional assays for hard-to-express GPCRs from all 3 structurally distinctive GPCR families, including Free Fatty Acid, Lysophospholipid, Prostanoid, Neuropeptide, Purinergic and Metabotropic Glutamate receptors ...