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Kebede MA, Oler AT, Gregg T, Balloon AJ, Johnson A, Mitok K, Rabaglia M, Schueler K, Stapleton D, Thorstenson C, Wrighton L, Floyd BJ, Richards O, Raines S, Eliceiri K, Seidah NG, Rhodes C, Keller MP, Coon JL, Audhya A, Attie AD. SORCS1 is necessary for normal insulin secretory granule biogenesis in metabolically stressed β cells. J Clin Invest 2014; 124:4240-56. [PMID: 25157818 DOI: 10.1172/jci74072] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 07/14/2014] [Indexed: 01/21/2023] Open
Abstract
We previously positionally cloned Sorcs1 as a diabetes quantitative trait locus. Sorcs1 belongs to the Vacuolar protein sorting-10 (Vps10) gene family. In yeast, Vps10 transports enzymes from the trans-Golgi network (TGN) to the vacuole. Whole-body Sorcs1 KO mice, when made obese with the leptin(ob) mutation (ob/ob), developed diabetes. β Cells from these mice had a severe deficiency of secretory granules (SGs) and insulin. Interestingly, a single secretagogue challenge failed to consistently elicit an insulin secretory dysfunction. However, multiple challenges of the Sorcs1 KO ob/ob islets consistently revealed an insulin secretion defect. The luminal domain of SORCS1 (Lum-Sorcs1), when expressed in a β cell line, acted as a dominant-negative, leading to SG and insulin deficiency. Using syncollin-dsRed5TIMER adenovirus, we found that the loss of Sorcs1 function greatly impairs the rapid replenishment of SGs following secretagogue challenge. Chronic exposure of islets from lean Sorcs1 KO mice to high glucose and palmitate depleted insulin content and evoked an insulin secretion defect. Thus, in metabolically stressed mice, Sorcs1 is important for SG replenishment, and under chronic challenge by insulin secretagogues, loss of Sorcs1 leads to diabetes. Overexpression of full-length SORCS1 led to a 2-fold increase in SG content, suggesting that SORCS1 is sufficient to promote SG biogenesis.
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Keating DH, Zhang Y, Ong IM, McIlwain S, Morales EH, Grass JA, Tremaine M, Bothfeld W, Higbee A, Ulbrich A, Balloon AJ, Westphall MS, Aldrich J, Lipton MS, Kim J, Moskvin OV, Bukhman YV, Coon JJ, Kiley PJ, Bates DM, Landick R. Aromatic inhibitors derived from ammonia-pretreated lignocellulose hinder bacterial ethanologenesis by activating regulatory circuits controlling inhibitor efflux and detoxification. Front Microbiol 2014; 5:402. [PMID: 25177315 PMCID: PMC4132294 DOI: 10.3389/fmicb.2014.00402] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 07/17/2014] [Indexed: 11/13/2022] Open
Abstract
Efficient microbial conversion of lignocellulosic hydrolysates to biofuels is a key barrier to the economically viable deployment of lignocellulosic biofuels. A chief contributor to this barrier is the impact on microbial processes and energy metabolism of lignocellulose-derived inhibitors, including phenolic carboxylates, phenolic amides (for ammonia-pretreated biomass), phenolic aldehydes, and furfurals. To understand the bacterial pathways induced by inhibitors present in ammonia-pretreated biomass hydrolysates, which are less well studied than acid-pretreated biomass hydrolysates, we developed and exploited synthetic mimics of ammonia-pretreated corn stover hydrolysate (ACSH). To determine regulatory responses to the inhibitors normally present in ACSH, we measured transcript and protein levels in an Escherichia coli ethanologen using RNA-seq and quantitative proteomics during fermentation to ethanol of synthetic hydrolysates containing or lacking the inhibitors. Our study identified four major regulators mediating these responses, the MarA/SoxS/Rob network, AaeR, FrmR, and YqhC. Induction of these regulons was correlated with a reduced rate of ethanol production, buildup of pyruvate, depletion of ATP and NAD(P)H, and an inhibition of xylose conversion. The aromatic aldehyde inhibitor 5-hydroxymethylfurfural appeared to be reduced to its alcohol form by the ethanologen during fermentation, whereas phenolic acid and amide inhibitors were not metabolized. Together, our findings establish that the major regulatory responses to lignocellulose-derived inhibitors are mediated by transcriptional rather than translational regulators, suggest that energy consumed for inhibitor efflux and detoxification may limit biofuel production, and identify a network of regulators for future synthetic biology efforts.
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Affiliation(s)
- David H Keating
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA
| | - Yaoping Zhang
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA
| | - Irene M Ong
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA
| | - Sean McIlwain
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA
| | - Eduardo H Morales
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA ; Department of Biomolecular Chemistry, University of Wisconsin-Madison Madison, WI, USA
| | - Jeffrey A Grass
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA ; Department of Biochemistry, University of Wisconsin-Madison Madison, WI, USA
| | - Mary Tremaine
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA
| | - William Bothfeld
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA
| | - Alan Higbee
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA
| | - Arne Ulbrich
- Department of Chemistry, University of Wisconsin-Madison Madison, WI, USA
| | - Allison J Balloon
- Department of Chemistry, University of Wisconsin-Madison Madison, WI, USA
| | - Michael S Westphall
- Department of Biomolecular Chemistry, University of Wisconsin-Madison Madison, WI, USA ; Department of Chemistry, University of Wisconsin-Madison Madison, WI, USA
| | - Josh Aldrich
- Pacific Northwest National Laboratory Richland, WA, USA
| | - Mary S Lipton
- Pacific Northwest National Laboratory Richland, WA, USA
| | - Joonhoon Kim
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA ; Department of Chemical and Biological Engineering, University of Wisconsin-Madison Madison, WI, USA
| | - Oleg V Moskvin
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA
| | - Yury V Bukhman
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA
| | - Joshua J Coon
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA ; Department of Biomolecular Chemistry, University of Wisconsin-Madison Madison, WI, USA ; Department of Chemistry, University of Wisconsin-Madison Madison, WI, USA
| | - Patricia J Kiley
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA ; Department of Biomolecular Chemistry, University of Wisconsin-Madison Madison, WI, USA
| | - Donna M Bates
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA
| | - Robert Landick
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison Madison, WI, USA ; Department of Biochemistry, University of Wisconsin-Madison Madison, WI, USA ; Department of Bacteriology, University of Wisconsin-Madison Madison, WI, USA
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