# Snustorr Defines Cuticle Elasticity in Drosophila melanogaster

## TL;DR

This study shows that the ABC transporter Snustorr is essential for lipid incorporation into the cuticle, supporting a decades-old hypothesis about how insect cuticles harden.

## Contribution

The study provides molecular evidence that Snustorr is required for lipid incorporation into the cuticle, confirming a historical hypothesis.

## Key findings

- Larvae lacking Snustorr have a 10-fold reduction in cuticle hardness compared to wild-type larvae.
- Snustorr is necessary for the incorporation of lipids into the cuticulin layer of the cuticle.
- The findings support Sir Vincent Wigglesworth's hypothesis that lipids contribute to insect cuticle hardening.

## Abstract

Sir Vincent Wigglesworth proposed in his seminal work on insect cuticle lipids that lipids are involved in cuticle hardening. In brief, in histological experiments, he demonstrated the presence of lipids as a component of cuticulin, a “hard amber material of the insect cuticle.” The molecular evidence for this postulate awaits demonstration. In the present work, we examined the cuticle of larvae lacking the function of the cuticle lipid transporter Snustorr (Snu) by nanoindentation with atomic force microscopy in order to analyze the role of lipids on cuticle hardness in the fruit fly Drosophila melnoagaster. Compared to wild‐type larvae, we found that the Young's modulus is 10 times reduced in snu mutant larvae that lack cuticulin at their surface. Thus, this simple result supports the finding of Sir Vincent Wigglesworth that lipids contribute to cuticle hardness in insects.

Based on histological experiments, Sir V. Wigglesworth proposed that lipids may interact with catecholamines and proteins to contribute to insect cuticle hardening. In this work, we show that the ABC transporter Snu is involved in the incorporation of lipids for this process.

Based on histological experiments, Sir V. Wigglesworth proposed that lipids may interact with catecholamines and proteins to contribute to insect cuticle hardening. In this work, we show that the ABC transporter Snu is involved in the incorporation of lipids for this process.

Sir Wigglesworth postulated that insect cuticle hardening depended on the incorporation of lipids into the upper parts of the cuticle. We show that the delivery of these lipids needed for cuticle hardening requires the ABC transporter Snu in the fruit fly Drosophila melanogaster larva.