Mobilization of Triacylglycerol Stores in Insects

Summary

Principal Investigator: ESTELA ARRESE
Affiliation: Oklahoma State University
Country: USA
Abstract: DESCRIPTION: (provided by the applicant): Unlike vertebrates, where the stored fatty acids are mobilized as free fatty acids, a great number of insects, mobilizes fatty acids as an-1, 2-diacylglycerol (DG). The mobilization of TG stores requires the action of a TG-lipase, whose activity is hormonally regulated. The substrate of the lipase (TG) is found in large intracellular lipid droplets, which are constituted by a core of TG surrounded by a complex surface layer of phospholipids and proteins. On the other hand, the TG-lipase localizes in the cytosol of lipolytically unstimulated fat body cells. Lipolysis involves the interaction of the lipase with the surface of the lipid droplet. It is known that activation of lipolysis promotes both an increase of intracellular calcium concentration and activation of amp-dependent protein kinase (A-kinase) but the basic mechanisms involved in how phosphorylation-dephosphorylation reactions modulate the rate of lipolysis is unknown. Moreover, little is known about the relevance and nature of the structural and compositional changes that affect the lipid droplet when lipolysis is hormonally activated. These changes must ultimately affect the interaction of the lipase with the lipid substrate and the concomitant activation of lipolysis. DG moves from the lipid droplet to the plasma membrane by an uncharacterized mechanism. It appears that after the conversion of TG into DG on the surface of the lipid droplets, DG would be transferred to a cytosolic carrier, which in turn would target the delivery of DG across the plasma membrane. The overall goals of this project are to establish the mechanisms regulating lipolysis by determining the factors that promotes the interaction between TG-lipase and its substrate, the lipid droplet and to define the mechanism of intracellular transport of DG. Clearly the elucidation of these mechanisms is of fundamental importance in insect biochemistry and physiology. These studies will provide comprehensive information on the lipolytic process in insects and this knowledge could also contribute to the broad field of lipid metabolism and transport in vertebrates.
Funding Period: 2002-02-01 - 2008-01-31
more information: NIH RePORT

Top Publications

  1. pmc TGL-mediated lipolysis in Manduca sexta fat body: Possible roles for lipoamide-dehydrogenase (LipDH) and high-density lipophorin (HDLp)
    Zengying Wu
    Department of Biochemistry and Molecular Biology, Oklahoma State University, 246 Noble Research Center, Stillwater, OK 74078, USA
    Insect Biochem Mol Biol 45:58-68. 2014
  2. pmc Membrane attachment and structure models of lipid storage droplet protein 1
    Penghui Lin
    Department of Physics, 230 L Henry Bellmon Research Center, Oklahoma State University, Stillwater, OK 74078, USA
    Biochim Biophys Acta 1838:874-81. 2014
  3. pmc Developmental changes in the protein composition of Manduca sexta lipid droplets
    Jose L Soulages
    Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74074, USA
    Insect Biochem Mol Biol 42:305-20. 2012
  4. pmc Mobilization of lipid stores in Manduca sexta: cDNA cloning and developmental expression of fat body triglyceride lipase, TGL
    Estela L Arrese
    Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, 74078, USA
    Insect Biochem Mol Biol 40:91-9. 2010
  5. pmc Insect fat body: energy, metabolism, and regulation
    Estela L Arrese
    Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74074, USA
    Annu Rev Entomol 55:207-25. 2010
  6. pmc Purification and characterization of recombinant lipid storage protein-2 from Drosophila melanogaster
    Estela L Arrese
    Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA
    Protein Pept Lett 15:1027-32. 2008
  7. pmc Expression of lipid storage droplet protein-1 may define the role of AKH as a lipid mobilizing hormone in Manduca sexta
    Estela L Arrese
    Department of Biochemistry and Molecular Biology, Oklahoma State University, 246 Noble Research Center, Stillwater, OK 74078, USA
    Insect Biochem Mol Biol 38:993-1000. 2008
  8. pmc Function and structure of lipid storage droplet protein 1 studied in lipoprotein complexes
    Estela L Arrese
    Department of Biochemistry and Molecular Biology, Oklahoma State University, 246 Noble Research Center, Stillwater, OK 74078, USA
    Arch Biochem Biophys 473:42-7. 2008
  9. ncbi Stimulation of lipolysis enhances the rate of cholesterol efflux to HDL in adipocytes
    Philip B Verghese
    Department of Biochemistry and Molecular Biology, Oklahoma State University, 147 Noble Research Center, Stillwater, OK 74078, USA
    Mol Cell Biochem 302:241-8. 2007
  10. ncbi The main triglyceride-lipase from the insect fat body is an active phospholipase A(1): identification and characterization
    Estela L Arrese
    Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA
    J Lipid Res 47:2656-67. 2006

Scientific Experts

  • ESTELA ARRESE
  • Jose L Soulages
  • Rajesh T Patel
  • Penghui Lin
  • Zengying Wu
  • Xiao Chen
  • Philip B Verghese
  • Bharat D Joshi
  • Zachary J Hager
  • Stuart M Daniel
  • Lian Duan
  • Liying Wang
  • Hem Moktan
  • Donghua H Zhou
  • Sarah J Firdaus
  • Alisha D Howard
  • Steve Hartson
  • Balaji Hariharasundaram

Detail Information

Publications12

  1. pmc TGL-mediated lipolysis in Manduca sexta fat body: Possible roles for lipoamide-dehydrogenase (LipDH) and high-density lipophorin (HDLp)
    Zengying Wu
    Department of Biochemistry and Molecular Biology, Oklahoma State University, 246 Noble Research Center, Stillwater, OK 74078, USA
    Insect Biochem Mol Biol 45:58-68. 2014
    ..Overall the study suggests that TGL occurs as a multi-protein complex supported by interactions through the WWE domain. ..
  2. pmc Membrane attachment and structure models of lipid storage droplet protein 1
    Penghui Lin
    Department of Physics, 230 L Henry Bellmon Research Center, Oklahoma State University, Stillwater, OK 74078, USA
    Biochim Biophys Acta 1838:874-81. 2014
    ..Juxtaposition of triglyceride lipase structure to the trans-model suggested a possible interaction of a conserved segment with the lipase by electrostatic interactions, opening the lipase lid to expose the catalytic center. ..
  3. pmc Developmental changes in the protein composition of Manduca sexta lipid droplets
    Jose L Soulages
    Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74074, USA
    Insect Biochem Mol Biol 42:305-20. 2012
    ..The compositions and compositional differences found among the LDs are discussed to provide a platform for future studies on the role of LDs, and their associated proteins, in cellular metabolism...
  4. pmc Mobilization of lipid stores in Manduca sexta: cDNA cloning and developmental expression of fat body triglyceride lipase, TGL
    Estela L Arrese
    Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, 74078, USA
    Insect Biochem Mol Biol 40:91-9. 2010
    ..This correlation and the expression pattern of TGL throughout development are consistent with the notion that TGL is the main fat body TG lipase of M. sexta...
  5. pmc Insect fat body: energy, metabolism, and regulation
    Estela L Arrese
    Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74074, USA
    Annu Rev Entomol 55:207-25. 2010
    ..This review focuses on energy storage and release and summarizes current understanding of the mechanisms underlying these processes in insects...
  6. pmc Purification and characterization of recombinant lipid storage protein-2 from Drosophila melanogaster
    Estela L Arrese
    Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA
    Protein Pept Lett 15:1027-32. 2008
    ..This study provides the starting point for future studies on the mechanism of function of Lsd2. The similarities and differences between Lsd1 and Lsd2, the only PAT proteins found in insects, are discussed...
  7. pmc Expression of lipid storage droplet protein-1 may define the role of AKH as a lipid mobilizing hormone in Manduca sexta
    Estela L Arrese
    Department of Biochemistry and Molecular Biology, Oklahoma State University, 246 Noble Research Center, Stillwater, OK 74078, USA
    Insect Biochem Mol Biol 38:993-1000. 2008
    ..Lsd1 was found in the fat body but it was undetectable in lipid droplets isolated from oocytes or embryos. The present study suggests a link between AKH-stimulated lipolysis in the fat body and the expression of Lsd1...
  8. pmc Function and structure of lipid storage droplet protein 1 studied in lipoprotein complexes
    Estela L Arrese
    Department of Biochemistry and Molecular Biology, Oklahoma State University, 246 Noble Research Center, Stillwater, OK 74078, USA
    Arch Biochem Biophys 473:42-7. 2008
    ..7-fold activation of the main fat body lipase demonstrating the direct link between Lsd1 phosphorylation and activation of lipolysis. Serine 20 was identified as the Lsd1-phosphorylation site triggering this effect...
  9. ncbi Stimulation of lipolysis enhances the rate of cholesterol efflux to HDL in adipocytes
    Philip B Verghese
    Department of Biochemistry and Molecular Biology, Oklahoma State University, 147 Noble Research Center, Stillwater, OK 74078, USA
    Mol Cell Biochem 302:241-8. 2007
    ..The study supports a metabolic link between the lipolytic activity of adipocytes and the rate of cellular cholesterol efflux to HDL...
  10. ncbi The main triglyceride-lipase from the insect fat body is an active phospholipase A(1): identification and characterization
    Estela L Arrese
    Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA
    J Lipid Res 47:2656-67. 2006
    ..These results suggest that the PL activity of the insect TG-lipase could be required to allow access of the lipase to TG molecules contained in the core of the lipid droplets...
  11. ncbi Adipokinetic hormone-induced mobilization of fat body triglyceride stores in Manduca sexta: role of TG-lipase and lipid droplets
    Rajesh T Patel
    Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA
    Arch Insect Biochem Physiol 63:73-81. 2006
    ..However, the phosphorylation level of the TG-lipase was unchanged by AKH, indicating that phosphorylation of the TG-lipase plays no role in the activation of lipolysis induced by AKH...
  12. ncbi Activation of the lipid droplet controls the rate of lipolysis of triglycerides in the insect fat body
    Rajesh T Patel
    Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, 74078, USA
    J Biol Chem 280:22624-31. 2005
    ..This activation is achieved by PKA-mediated phosphorylation of the lipid droplet. Lsdp1 is the main target of PKA, suggesting that this protein is a major player in the activation of lipolysis in insects...