FNIP1 and FNIP2 were identified as proteins interacting with tumor suppressor folliculin. FNIP1 and FNIP2 directly associate with AMPK, which indicates that they play roles in the energy and nutrient sensing pathways. Further studies show that the FLCN/FNIP2 complex functions as a GTPase-activating protein for Rag GTPase C and Rag GTPase D. The FLCN/FNIP2 complex thus promotes binding of mTORC1 to Rag heterodimers, leading to mTORC1 activation. In addition, along with FLCN, both FNIP1 and FNIP2 contribute to kidney tumor suppression.
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