FNIP2
Description
The FNIP2 (folliculin interacting protein 2) is a protein-coding gene located on chromosome 4.
FNIP2 is a binding partner of the GTPase-activating protein FLCN, playing a crucial role in cellular response to amino acid availability. It regulates the non-canonical mTORC1 signaling cascade, which controls the MiT/TFE factors TFEB and TFE3. FNIP2 promotes FLCN recruitment to lysosomes and interaction with Rag GTPases, activating the non-canonical mTORC1 signaling. Under low amino acid conditions, FNIP2 forms part of the lysosomal folliculin complex (LFC) on the lysosomal membrane, inhibiting FLCN's GTPase-activating activity, inactivating mTORC1 and promoting nuclear translocation of TFEB and TFE3. When amino acids are restimulated, the LFC complex disassembles, freeing FLCN's GTPase-activating activity, activating mTORC1 and subsequently inactivating TFEB and TFE3. Alongside FLCN, FNIP2 regulates autophagy. Following phosphorylation by ULK1, FNIP2 interacts with GABARAP and promotes autophagy.
FNIP2 is also known as FNIPL, MAPO1.
