FIGURE 11.

Diagram showing a plausible mechanism through which Cat-1 functions in HeLa cells to promote cellular transformation. Cat-1 binds to paxillin to abrogate its actions as a negative regulator of anchorage-independent growth (left). Specifically, the interaction between Cat-1 and paxillin perturbs the ability of paxillin to activate the Arf1-mTORC1-p70S6 kinase pathway, which ensures that the necessary level of AKT activation needed for supporting anchorage-independent growth (i.e. colony formation in soft agar) is met. However, under conditions where Cat-1 is knocked down (right), the Arf1-mTORC1-p70S6 kinase pathway is activated, leading to a p70S6 kinase-mediated negative regulation of Akt activity and loss of anchorage-independent growth.