THE EFFECT OF RHEB EXPRESSION IN THORACIC MUSCLE DURINGTHE MOLT CYCLE IN GECARCINUS LATERALIS

This study aimed to detecte the role of Rheb in the molting cycle of Gecarcinus lateralis. Skeletal muscle atrophy in crustaceans is necessary for the progression of molting. The atrophy of thoracic muscles is coordinated by the action of ecdysteroid hormones. Thoracic muscle atrophy can occur during the intermolt period when hemolymph ecdysteroid levels are low. The insulin/mechanistictarget of rapamycin (mTOR) pathway, previously shown to be important for growth, development, reproduction, and metamorphosis in insects, is a likely target of ecdysteroid regulation. As complete cDNAs for ras homolog enriched in brain (Rheb) the key activator of mTOR, have been cloned from Gecarcinus lateralis. Levels of Rheb increase dramatically during molting induced by either Eyestalk Ablation (ESA) or Multiple Limb Autotomy (MLA) and showed a correlation with levels of ecdysteroid in the thoracic muscle, in both molting paradigms. Our findiings  indicate that Gl-Rheb is an important activator of crustacean mTOR signaling in the molt cycle in response to ecdysteroids.