As a component of the GATOR2 complex, functions as an activator of the amino acid-sensing branch of the mTORC1 signaling pathway. The GATOR2 complex indirectly activates mTORC1 through the inhibition of the GATOR1 subcomplex. GATOR2 probably acts as an E3 ubiquitin-protein ligase toward GATOR1. In the presence of abundant amino acids, the GATOR2 complex mediates ubiquitination of the NPRL2 core component of the GATOR1 complex, leading to GATOR1 inactivation. In the absence of amino acids, GATOR2 is inhibited, activating the GATOR1 complex. Within the GATOR2 complex, MIOS is required to prevent autoubiquitination of WDR24, the catalytic subunit of the complex. The GATOR2 complex is required for brain myelination