Component of the hard and soft cuticles of the larva and pupa of Tenebrio molitor. Restricted to sternal, tergal, legs and wing anlagen epidermis, and soft cuticle secreting epidermis, such as intersegmental membranes and pleura. No expression in muscles or fat body. Expressed in epidermal cells during the secretion of preecdysial larval and pupal cuticles. Restricted to a short part of the intersegmental regions after pupal ecdysis. By juvenile hormone. The tetrapeptide (A-A-P-[AV]) repeats found throughout the protein are also present in many proteins constituting the protective envelope of other species.