TGFB1 and hepatocellular carcinoma: Yeast two-hybrid analysis reveals that LAPTM5 is an interacting partner of Smurf2, an E3-ubiquitin ligase associated with the degradation of TGFβ signaling components that include the TGFβ receptor and Smad proteins, in human hepatocellular carcinoma HepG2 cells [6, 7]; the expression of LAPTM5 mRNA increased 20-fold in HepG2 cells following TGFβ treatment.