FIP200 (FAK-family interacting protein of 200 kDa) appears to play several key roles related to cell growth, proliferation, development, and tumorigenesis. FIP200 was originally identified in a yeast two-hybrid screen for Pyk2 kinase interacting proteins. It was later identified as a protein that interacts with FAK (focal adhesion kinase), a signal transducing protein that mediates signals from the extracellular matrix to the cytoskeleton to influence cell motility, and cell cycle progression. FIP200 is also known as RB1CC1 (RB1-inducible coiled-coil 1) and has been found to function as a regulator of the retinoblastoma 1 (RB1) tumor suppressor. FIP200 associates with the tumor suppressor TSC1 which partners with TSC2 to antagonize the mTOR signaling pathway. FIP200 association with TSC2 promotes mTOR activity by interfering with the antagonistic effects of the TSC1-TSC2 complex.