The mechanistic target of rapamycin (mTOR) signal-transduction pathway plays a key role in regulating many aspects of metabolic processes. The central player of the mTOR signaling pathway, mTOR complex 1 (mTORC1), is recruited by the pentameric Ragulator complex and the heterodimeric Rag GTPase complex to the lysosomal membrane and thereafter activated. Here, we determined the crystal structure of the human Ragulator complex, which shows that Lamtor1 possesses a belt-like shape and wraps the other four subunits around. Extensive hydrophobic interactions occur between Lamtor1 and the Lamtor2-Lamtor3, Lamtor4-Lamtor5 roadblock domain protein pairs, while there is no substantial contact between Lamtor2-Lamtor3 and Lamtor4-Lamtor5 subcomplexes. Interestingly, an α-helix from Lamtor1 occupies each of the positions on Lamtor4 and Lamtor5 equivalent to the α3-helices of Lamtor2 and Lamtor3, thus stabilizing Lamtor4 and Lamtor5. Structural comparison between Ragulator and the yeast Ego1-Ego2-Ego3 ternary complex (Ego-TC) reveals that Ego-TC only corresponds to half of the Ragulator complex. Coupling with the fact that in the Ego-TC structure, Ego2 and Ego3 are lone roadblock domain proteins without another roadblock domain protein pairing with them, we suggest that additional components of the yeast Ego complex might exist.

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Compared with a single piezoelectric poly(vinylidene fluoride) (PVDF) sheet, a bimorph can enhance driving performance. The main aim of this work is to study a soft piezoelectric bimorph as an actuator used in a soft sail. PVDF samples were prepared using a hightemperature solvent evaporation method and were then drawn and poled. The crystalline phase, mechanical properties, piezoelectric property and energy-harvesting performance were analyzed. A PVDF piezoelectric bimorph was designed. The capacity of deformation of the parallel bimorph with a pulsed electric field was studied. The deformation of the sample increased almost linearly, and the deformation performance was obvious with the increase in voltage. To evaluate its driving performance in the engineering model, a sail made of Kapton was produced, and the PVDF bimorph was used as an actuator to drive the sail. The deformation was observed by a Video-Simultaneous Triangulation and Resection System. Furthermore, the finite element method was used to further understand the actuation effect of the Kapton sail matrix and PVDF bimorph actuator according to three different laying methods.

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