Folliculin Interacting Protein 1 (FNIP1)

FNIP1 interacted with HSP90 (HSPCA) and with the alpha (PRKAA1), beta (PRKAB1), and gamma (PRKAG1) subunits of AMPK. FNIP1 was phosphorylated by AMPK, and its phosphorylation was inhibited in a dose-dependent manner by an AMPK inhibitor, resulting in reduced FNIP1 expression. FLCN phosphorylation was diminished by rapamycin and amino acid starvation and facilitated by FNIP1 overexpression, suggesting that FLCN phosphorylation may be regulated by mTOR (FRAP1; 601231) and AMPK signaling. FLCN and FNIP1 may be involved in energy and/or nutrient sensing through the AMPK and mTOR signaling pathways.The deduced 1,166-amino acid protein has no known functional domains. Expression of FNIP1 in HEK293 cells yielded a protein that migrated at 130 kD on SDS-PAGE.