Sec8 and Myo15 regulate epidermal chitin synthase localization and cuticular chitin biosynthesis.

Area of Science:

• Insect molecular biology
• Biochemistry
• Cell biology

Background:

• Chitin synthase 1 (Chs1) is vital for insect cuticle formation, catalyzing chitin biosynthesis.
• Correct localization of Chs1 to the apical plasma membrane is essential for chitin deposition, but regulatory mechanisms are unknown.

Purpose of the Study:

• To identify proteins that regulate the membrane localization of Chitin synthase 1 (Chs1).
• To elucidate the molecular mechanisms governing Chs1 localization and its role in insect development.

Main Methods:

• TurboID-based proximity biotinylation in Drosophila melanogaster to identify the Chs1 proximal proteome.
• Split-ubiquitin membrane yeast two-hybrid and pull-down assays to confirm protein interactions.
• RNA interference (RNAi) in Tribolium castaneum to assess the function of candidate proteins.

Main Results:

• Identified DmSec8 and DmMyo15 as interacting partners of Chs1 (Kkv).
• Confirmed physical interactions between Kkv and DmSec8/DmMyo15.
• Silencing Sec8 or Myo15 in Tribolium castaneum led to lethality, molting defects, reduced chitin, and Chs1 mislocalization.

Conclusions:

• Sec8 and Myo15 are novel regulators of Chs1 membrane localization.
• These findings provide new insights into the molecular control of chitin biosynthesis and insect development.