Cloning and characterization of a gut-specific cathepsin L from the aphid Aphis gossypii

Insect Mol Biol. 2004 Apr;13(2):165-77. doi: 10.1111/j.0962-1075.2004.00474.x.


We have characterized proteinase activities in gut extracts from the cotton-melon aphid (Aphis gossypii Glover), an insect feeding strictly on protein-poor phloem. The major, if not exclusive, intestinal proteinases of this aphid are of the cysteine type. A cDNA has been cloned from a gut library and codes for the cysteine proteinase AgCatL, a cathepsin L-like cysteine proteinase. The AgCatL protein shows high sequence similarity with mammalian and some arthropod cathepsin L-like proteinases, but can be reliably distinguished from the secreted (digestive) proteinases identified in other arthropods. AgCatL is widely expressed in aphid intestinal cells. Immunolocalization of AgCatL showed an intense signal at the level of the anterior 'stomach' part of the midgut, and especially at intracellular localization. Although the precise role of AgCatL in aphid midgut physiology is still unclear, this enzyme could be involved in the processing of exogenous ingested polypeptides.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Aphids / enzymology*
  • Cathepsin L
  • Cathepsins / genetics*
  • Cathepsins / isolation & purification
  • Cluster Analysis
  • Cysteine Endopeptidases / genetics*
  • Cysteine Endopeptidases / isolation & purification
  • DNA Primers
  • DNA, Complementary / genetics
  • Digestive System / enzymology*
  • Electrophoresis, Polyacrylamide Gel
  • Hydrogen-Ion Concentration
  • Immunoblotting
  • Immunohistochemistry
  • Molecular Sequence Data
  • Phylogeny*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sequence Analysis, DNA
  • Sequence Homology


  • DNA Primers
  • DNA, Complementary
  • Cathepsins
  • Cysteine Endopeptidases
  • Cathepsin L