Mechanical control of the insect extracellular matrix nanostructure

Nanoscale modifications of apical extracellular matrix (ECM) have created a variety of functional surfaces with distinct physical properties, as exemplified by structural coloration and superhydrophobicity in animals and plants1. While the surface nanostructures of various organisms have inspired numerous biomimetic applications, the biological mechanisms underlying ECM patterning at the nanoscale remain largely unknown. Here, we investigated the morphogenesis of cuticular pores in Drosophila olfactory organs2,3. Hundreds of uniform-sized nanopores of [~]50 nm permit selective access of odorant molecules to olfactory neurons. We showed that matrices composed of the zona pellucida domain (ZPD) protein4-6 cover sensory organs in cell type-specific patterns and combinations. The ZPD proteins Dyl, Tyn, Mey, and Nyo form matrices with specific mixing and sorting properties, restricting cell growth and movement. The disruption of ZPD matrices leads to detachment of the envelope layer of the cuticle from the plasma membrane, and reduced numbers and irregularly sized nanopores. Our results suggest that compressive force from the ECM is essential for robust nanopore morphogenesis. This work reveals a previously unrecognized role for ZPD proteins as modular units that establish the mechanical environment required to modulate the nanoscale assembly of cuticle materials, opening a new biological context to these biomimetically important structures.