Expression of lipid storage droplet protein-1 may define the role of AKH as a lipid mobilizing hormone in Manduca sexta

Insect Biochem Mol Biol. 2008 Nov;38(11):993-1000. doi: 10.1016/j.ibmb.2008.08.004. Epub 2008 Aug 26.

Abstract

Adipokinetic hormone (AKH) is the main hormone involved in the acute regulation of hemolymph lipid levels in several insects. In adult Manduca sexta AKH promotes a rapid phosphorylation of "Lipid storage protein-1", Lsd1, and a concomitant activation of the rate of hydrolysis of triglycerides by the main fat body lipase. In contrast, in the larval stage AKH modulates hemolymph trehalose levels. The present study describes the sequence of a full-length Lsd1 cDNA obtained from M. sexta fat body and investigates a possible link between Lsd1 expression and the distinct effects of AKH in larva and adult insects. The deduced protein sequence showed a high degree of conservation compared to other insect Lsd1s, particularly in the central region of the protein (amino acids 211-276) in which the predicted lipid binding helices are found. Lsd1 was absent in feeding larva and its abundance progressively increased as the insect develops from the non-feeding larva to adult. Contrasting with the levels of protein, Lsd1 transcripts were maximal during the feeding larval stages. The subcellular distribution of Lsd1 showed that the protein exclusively localizes in the lipid droplets. 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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cloning, Molecular
  • Conserved Sequence
  • DNA, Complementary / chemistry
  • Fat Body / metabolism
  • Insect Hormones / pharmacology
  • Insect Hormones / physiology*
  • Insect Proteins / analysis
  • Insect Proteins / genetics
  • Insect Proteins / metabolism*
  • Lipid Metabolism*
  • Manduca / drug effects
  • Manduca / genetics
  • Manduca / growth & development
  • Manduca / metabolism*
  • Molecular Sequence Data
  • Oligopeptides / pharmacology
  • Oligopeptides / physiology*
  • Pyrrolidonecarboxylic Acid / analogs & derivatives*
  • Pyrrolidonecarboxylic Acid / pharmacology
  • Sequence Alignment

Substances

  • DNA, Complementary
  • Insect Hormones
  • Insect Proteins
  • Oligopeptides
  • adipokinetic hormone
  • Pyrrolidonecarboxylic Acid