Insects (Dec 2023)

Mosquitoes Possess Specialized Cuticular Proteins That Are Evolutionarily Related to the Elastic Protein Resilin

  • Sakura Ohkubo,
  • Tohki Shintaku,
  • Shotaro Mine,
  • Daisuke S. Yamamoto,
  • Toru Togawa

DOI
https://doi.org/10.3390/insects14120941
Journal volume & issue
Vol. 14, no. 12
p. 941

Abstract

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Resilin is an elastic protein that is vital to insects’ vigorous movement. Canonical resilin proteins possess the R&R Consensus, a chitin-binding domain conserved in a family of cuticular proteins, and highly repetitive sequences conferring elastic properties. In the malaria vector mosquito, Anopheles gambiae, however, a cuticular protein has been found that has an R&R Consensus resembling that of resilin but lacks the repetitive sequences (here, we call it resilin-related or resilin-r). The relationship between resilin-r and resilin was unclear. It was also unknown whether resilin-r is conserved in mosquitoes. In this paper, phylogenetic and structural analyses were performed to reveal the relationship of resilin homologous proteins from holometabolous insects. Their chitin-binding abilities were also assessed. A resilin-r was found in each mosquito species, and these proteins constitute a clade with resilin from other insects based on the R&R Consensus sequences, indicating an evolutionary relationship between resilin-r and resilin. The resilin-r showed chitin-binding activity as same as resilin, but had distinct structural features from resilin, suggesting that it plays specialized roles in the mosquito cuticle. Another resilin-like protein was found to exist in each holometabolous insect that possesses resilin-like repetitive sequences but lacks the R&R Consensus. These results suggest that similar evolutionary events occurred to create resilin-r and resilin-like proteins.

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