Non-lytic insect-based protein expression system Triple Express combines an expression cassette engineered from the silk moth cytoplasmic actin A3 gene, a strong, constitutive cellular promoter, an enhancer element, and a transcriptional activator that enhances the production of recombinant proteins up to 5000 fold. With the system, the quality of expressed proteins is enhanced both through reduced protein degradation, owing to the non-lytic nature of the system, and consistent post-translational modifications. The system is amenable to both transient and stable production, and can be used for both small- and large-scale expression of membrane, cytoplasmic and nuclear proteins.