Our research lies in the broad area of the molecular mechanisms that underlie metabolic homeostasis and its relationship to cell growth control. We have discovered a signaling pathway comprising the protein kinase GSK3, acetyltransferase TIP60, and protein kinase ULK1, which activates autophagy in cells deprived of serum, elucidating the molecular mechanism linking nutritional starvation to autophagy. We have also revealed that the ULK kinases phosphorylate multiple glycolytic enzymes and regulate glucose metabolic fluxes dependently of autophagy. 

    The main focus of our research has also been on the mechanisms for the regulation of the AMP-activated protein kinase. We have shown that the lowenergy signal AMP can autonomously initiate assembly of an activating complex for the energy sensor kinase AMPK, in that the scaffold protein AXIN tethers LKB1 to AMPK. Moreover, we have found that the AXIN/LKB1/AMPK complex and mTORC1 inversely utilize the common v-ATPaseRagulator complex for activation on the surface of lysosome, thereby uncovering a switch between anabolism and catabolism. We are exploring further how AMPK and its activating kinase LKB1 are regulated and the biological functions of these kinases.