CAREER: Understanding the Molecular Mechanisms of Insect Cuticular Chitin Maintenance

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Insects and other arthropods have a hard exoskeleton or cuticle, which must be shed in a process called molting for the animal to grow. This NSF CAREER Award aims to investigate mechanisms involved in insect cuticle formation by testing three possible mechanisms whereby the newly synthesized cuticle is protected from degradation during molting as the old cuticle is broken down by enzymes. While insects provide numerous benefits to humankind, they can also inflict extensive damage to crops and serve as vectors for pathogens that cause deadly diseases. Therefore, the research results could lead to innovative pest and vector management strategies. The acquired knowledge will be integrated into existing curricula and active learning approaches involving 3-D visualization modules on insect physiology will be developed, thereby enhancing the educational impact of the project. The project will offer multidisciplinary training to undergraduate and graduate students in the fields of insect physiology, biochemistry, molecular biology, and bioinformatics. By providing underprivileged and underrepresented minority female undergraduate students from local institutions with comprehensive laboratory research experiences and opportunities to present their work at regional/national conferences, the project seeks to empower those students to pursue STEM-based careers.Chitin serves as a crucial structural component of the insect cuticle (exoskeleton), peritrophic matrix (gut lining), trachea, and eggshell. Insects periodically replace their old cuticle through molting or ecdysis to accommodate growth. During each molt, a new cuticle forms, while the old one simultaneously undergoes partial degradation by chitinases before being shed. Notably, chitinases do not degrade the new cuticular chitin despite being abundant in the procuticle. Previous research has demonstrated the critical role of the protein Knickkopf (Knk) in preventing premature degradation of the new cuticle by chitinases, albeit through an unknown mechanism. This CAREER project investigates how newly synthesized cuticular chitin is shielded from chitinase activity during molting to ensure the integrity of the newly forming cuticle. It will test the hypothesis that chitin deacetylases play a pivotal role in maintaining cuticle integrity by shielding against chitinases, potentially in collaboration with Knk. The project will (1) examine the impact of chitin deacetylation on chitinase function, (2) identify accessory proteins required for chitin deacetylase function, and (3) assess the importance of chitin deacetylation in gut peritrophic matrix integrity. To better understand the function of chitin deacetylases in maintaining cuticle integrity, the research will employ, and train students in, various molecular biology, confocal microscopy, transmission electron microscopy and mass-spectrometry techniques.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.