Protein glycosylation in insects: types, functions, and variation

Protein glycosylation, or the modification of proteins with carbohydrate structures, is a fundamental post-translational modification that plays a pivotal role in the biology of insects. Glycans influence multiple physiological processes, including development, immunity, cell attachment, and intercellular communication by modulating the stability, localization, and activity of the proteins they decorate. While the general principles of glycosylation are conserved throughout eukaryotes, insects possess a distinct repertoire of glycan structures. This review provides a comprehensive overview of glycosylation in insects, beginning with the glycosylation pathways and the enzymatic machinery involved. Subsequently, the unique structural features and diversity compared to other taxa are discussed. Special attention is given to microvariations in glycan composition and structure at the cellular, tissue, and organismal levels, revealing dynamic regulation and context-dependent expression. Finally, we discuss the functional implications of glycosylation in insects. Together, these insights underscore the complexity and biological significance of glycosylation in insect physiology and open avenues for future research in glycobiology and insect biotechnology.