The yeast serine threonine kinase Atg1 appears to be a key regulator of autophagy and its kinase activity is crucial for autophagy induction. Recent reports have indicated that a mammalian Atg1 homolog, UNC-51-like kinase (ULK) 1, is required for autophagy. We found that ULK1 localizes to the autophagic isolation membrane and its kinase activity is important for autophagy induction. Furthermore, we identified a focal adhesion kinase (FAK) family interacting protein of 200 kD (FIP200) as a ULK-interacting protein. FIP200 also localizes to the isolation membrane together with ULK. Using FIP200-deficient cells, we found that FIP200 is essential for autophagosome formation and the proper function of ULK. Here, we discuss the role of the ULK-FIP200 complex in autophagy and the possibility that FIP200 functions as a mammalian counterpart of Atg17.
T Hara, A Takamura, C Kishi, S Iemura, T Natsume, JL Guan, N Mizushima. FIP200, a ULK-interacting protein, is required for autophagosome formation in mammalian cells. J Cell Biol 2008; 181: 497- 510.
PMID: 18443221 DOI: 10.1083/jcb.20071206