FLCN has been shown to bind FNIP1, FNIP2, the Rag GTPases A and C/D, GABARAP and plakophilin-4 (refs 11, 12, 13, 14, 15, 16, 17, 18), but the biological significance of each of these interactions with regards to the tumour suppressor function of FLCN is under investigation. Here, FNIP2 is linked to neoplasm.