RASSF1A is one of the most epigenetically silenced gene in human cancers and an important negative regulator of NFkB activation and potential tumor suppressor. It is required for death receptor-dependent apoptosis. It also mediates activation of STK3/MST2 and STK4/MST1 during Fas-induced apoptosis by preventing their dephosphorylation. When associated with MOAP1，promotes BAX conformational change and translocation to mitochondrial membranes in response to TNF and TNFSF10 stimulation. Isoform A interacts with CDC20，an activator of the anaphase-promoting complex，APC，resulting in the inhibition of APC activity and mitotic progression. RASSF1A inhibits proliferation by negatively regulating cell cycle progression at the level of G1/S-phase transition by regulating accumulation of cyclin D1 protein. Isoform C has been shown not to perform these roles; no function has been identified for this isoform. Isoform A disrupts interactions among MDM2，DAXX and USP7，thus contributing to the efficient activation of TP53 by promoting MDM2 self-ubiquitination in cell-cycle checkpoint control in response to DNA damage.
