This is the middle domain of folliculin-interacting proteins [1,2].

1: Interaction of folliculin (Birt-Hogg-Dube gene product) with a novel Fnip1-like (FnipL/Fnip2) protein. Takagi Y, Kobayashi T, Shiono M, Wang L, Piao X, Sun G, Zhang D, Abe M, Hagiwara Y, Takahashi K, Hino O; Oncogene. 2008;27:5339-5347. PMID:18663353

2: Identification and characterization of a novel folliculin-interacting protein FNIP2. Hasumi H, Baba M, Hong SB, Hasumi Y, Huang Y, Yao M, Valera VA, Linehan WM, Schmidt LS; Gene. 2008;415:60-67. PMID:18403135