Mechanical control of the insect extracellular matrix nanostructure

Nanoscale modifications of apical extracellular matrix (ECM) have created various functional surfaces with distinct physical properties, exemplified by structural coloration and superhydrophobicity in animals and plants. To reveal the mechanisms, we investigated cuticle morphogenesis in Drosophila olfactory organs, where hundreds of ~50-nanometer nanopores in the cuticle covering the olfactory neurons permit selective odorant entry. We showed that zona pellucida domain (ZPD) proteins form the cell type-specific ECM compartments before cuticle secretion, and its disruption leads to less and irregularly sized nanopores. The ZPD protein Dusky-like controls the formation of the outermost layer of the cuticle, the envelope. Trynity, Nyobe, Neo, and Morpheyus form matrices with specific mixing and sorting properties, termed "cloud ECM," which restrict cell growth and movement. This work identifies a previously unidentified role for ZPD proteins as modular units that establish the mechanical environment essential for nanoscale ECM morphogenesis, opening a previously unexplored context for these biomimetically important structures.