Mammalian target of rapamycin (mTOR), which is now referred to as mechanistic target of rapamycin, integrates many signals, including those from growth factors, energy status, stress, and amino acids, to regulate cell growth and proliferation, protein synthesis, protein degradation, and other physiological and biochemical processes. The mTOR-Rheb-TSC-TBC complex co-localizes to the lysosome and the phosphorylation of TSC-TBC effects the dissociation of the complex from the lysosome and activates Rheb. GTP-bound Rheb potentiates the catalytic activity of mTORC1. Under conditions with growth factors and amino acids, v-ATPase, Ragulator, Rag GTPase, Rheb, hVps34, PLD1, and PA have important but disparate effects on mTORC1 activation. In this review, we introduce five models of mTORC1 activation by growth factors and amino acids to provide a comprehensive theoretical foundation for future research.

Elongation of very-long-chain fatty acids 1 (ELOVL1) is a ubiquitously expressed gene that belongs to the ELOVL family and regulates the synthesis of very-long-chain fatty acids (VLCFAs) and sphingolipids, from yeast to mammals. Mammalian target of rapamycin complex 1 (mTORC1) is a central regulator of cell metabolism and is associated with fatty acids synthesis. In this study, we cloned the cDNA that encodes Cashmere goat (Capra hircus) ELOVL1 (GenBank Accession number KF549985) and investigated its expression in 10 tissues. ELOVL1 cDNA was 840 bp, encoding a deduced protein of 279 amino acids, and ELOVL1 mRNA was expressed in a wide range of tissues. Inhibition of mTORC1 by rapamycin decreased ELOVL1 expression and fatty acids synthesis in Cashmere goat fetal fibroblasts. These data show that ELOVL1 expression is regulated by mTORC1 and that mTORC1 has significant function in fatty acids synthesis in Cashmere goat.

Lignin peroxidase is one of a series of enzymes involved in lignin degradation and is secreted by white-rot fungi. However, white-rot fungi have a long growth cycle and low enzyme activity, which limits their application. An efficient and stable heterologous expression system might be the solution to overcome these critical limitations. In this study, the lignin peroxidase gene of white-rot fungus (Phanerodontia chrysosporium) was cloned and heterologously expressed in the food-grade yeast Cyberlindnera jadinii for the first time. The strain ZHMX4 expressing lignin peroxidase was constructed, and its genetic stability, enzyme activity and phenotypic analysis were evaluated. ZHMX4 retained and maintained genetic stability for up to 100 generations. Its lignin peroxidase activity reached a maximum at 96 h with 68.52 U/L. Phenotypic analysis (Biolog) showed obvious changes in the substrate metabolism of the engineered strain compared to Cyberlindnera jadinii. Thus, ZHMX4 is a food-grade genetically engineered strain with great potential for lignin degradation. This study successfully expressed lignin peroxidase in Cyberlindnera jadinii as a new approach for the biodegradation of lignin. These findings should be useful for further academic studies, industrial applications of lignin peroxidase and construction of artificial white-rot fungi.