The main focus of the Li laboratory is to elucidate the molecular basis of protein-protein interaction and understand how aberrant changes in protein function and connectivity alter cellular behaviour and lead to diseases.

In epithelial cells under a physiological condition, Numb is involved in stabilization of cell-cell adhesions by binding to E-cadherin or binding to the Par complex via Par3. Upon HGF engagement of the c-Met receptor, one of the downstream components, the c-Src kinase is activated, which leads to tyrosine phosphorylation of E-cadherin (presumably on the YYY triad) and the decoupling of Numb from phospho-E-cadherin consequently. In the meantime, Numb sequesters phosphorylated aPKC and Par6 but releases Par3. The NumbaPKC-Par6 complex may be retained on the plasma membrane or in the cytosol, while Par3 is translocated into the nucleus.