Use of leucyl tRNA synthetase

A method for screening for an agent for treating mTORC1 (mammalian target of rapamycin complex 1)-mediated diseases, the method comprising:

• applying test agents to mixtures comprising LRS (Leucyl tRNA synthetase) and RagD (RagD GTPase) to provide test mixtures;
• measuring a binding affinity between LRS and RagD in each of the test mixtures;
• comparing the measured binding affinity between LRS and RagD in each of the test mixtures with the test agents applied thereto, to a binding affinity between LRS and RagD in a control mixture without a test agent, wherein a decrease in binding affinity between LRS and RagD in at least one of the test mixtures in comparison to the control mixture provides an indication that at least one of the test agents in the at least one test mixture inhibits binding affinity between LRS and RagD;
• identifying the at least one test agent in the at least one test mixture that inhibits the binding affinity between LRS and RagD, based on the comparison;
• and
• evaluating the at least one test agent in the at least one test mixture that inhibits the binding affinity between LRS and RagD as an agent for treating a mTORC1-mediated disease selected from the group consisting of cancer, autoimmune disease, diabetes, obesity, and cardiovascular disease.