Small regulatory polypeptide of amino acid response

[Isoform 2]: Negative regulator of amino acid sensing and mTORC1, a signaling complex promoting cell growth in response to growth factors, energy levels and amino acids. Negatively regulates mTORC1 activation by inhibiting recruitment of mTORC1 to lysosomes upon stimulation with amino acids: acts by promoting the formation of a tightly bound supercomplex composed of the lysosomal V-ATPase, Ragulator and Rag GTPases, preventing recruitment of mTORC1. Acts as a regulator of muscle regeneration following injury by regulating mTORC1 activation (By similarity).