FLCN and Birt-Hogg-Dubé syndrome: FLCN/FNIP associates with lysosome following serum and amino acid withdrawal, binds nucleotide free RagA/B and acts as a GTPase activating protein (GAP) for RagC to promote the recruitment and activation of mTORC1 on lysosomes 37, 38, 39, although FLCN loss in BHD syndrome can result in elevated mTORC1 activity in kidney tumours 40, 41.