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Rearing and Injection of Manduca sexta Larvae to Assess Bacterial Virulence
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Published on: December 11, 2012

A novel ML protein from Manduca sexta may function as a key accessory protein for lipopolysaccharide signaling

Jing-qun Ao1, Erjun Ling, Xiang-jun Rao

  • 1Division of Cell Biology and Biophysics, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110, USA.

Molecular Immunology
|March 18, 2008
PubMed

Insights

Researchers identified a novel MD-2-related lipid-recognition (ML) protein, MsML-1, in the tobacco hornworm Manduca sexta. This protein binds to lipopolysaccharide (LPS) and may play a role in innate immunity against Gram-negative bacteria.

Area of Science:

  • Invertebrate immunology
  • Molecular biology
  • Biochemistry

Background:

  • Lipopolysaccharide (LPS) is a key pathogen-associated molecular pattern on Gram-negative bacteria, crucial for innate immunity.
  • In humans, LPS recognition involves Toll-like receptor 4 (TLR4) and myeloid differentiation-2 (MD-2).
  • LPS receptors in invertebrates remain largely undetermined.

Purpose of the Study:

  • To identify and characterize proteins involved in LPS recognition in the tobacco hornworm, Manduca sexta.
  • To elucidate the function of a novel MD-2-related lipid-recognition (ML) protein in M. sexta innate immunity.

Main Methods:

  • Purification and characterization of an ML protein from M. sexta.
  • cDNA cloning and sequencing of the identified ML protein (MsML-1).
  • Analysis of MsML-1 expression in different tissues and hemolymph.
  • Binding assays using recombinant MsML-1 with LPS, lipid A, and related molecules.

Main Results:

  • A novel M. sexta ML protein, MsML-1, was identified, encoded by a 532bp cDNA with a 151-amino acid polypeptide.
  • MsML-1 is a secreted glycoprotein expressed in fat body and hemocytes, with constitutive levels in hemolymph.
  • Recombinant MsML-1 specifically binds to LPS, LPS Re mutant, and lipid A, but not KDO.

Conclusions:

  • MsML-1 functions as a key accessory protein for lipopolysaccharide (LPS) signaling in Manduca sexta.
  • This finding provides insight into invertebrate innate immune mechanisms against Gram-negative bacterial infections.
  • MsML-1 represents a potential target for understanding insect immunity and host-pathogen interactions.

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