FIG. 7.

SOD3 regulation of signal transduction. (A) Low level of SOD3 expression increases RTK and SRC phosphorylation and allows signaling through small GTPase RAS by increasing GEF expression and decreasing GAP and GDI expression. (B) High level of SOD3 expression increases RTK and SRC phosphorylation but inactivates small GPTase RAS by decreasing GEF expression and increasing GAP and GDI expression. Thereby, the signal does not proceed to mitogenic pathway. (C) High level of SOD3 expression increases WWTR1 and AXIN2 expression inhibiting β-CATENIN nuclear entry, which then attenuates growth. AXIN2, axis inhibition protein 2; GDI, guanine nucleotide disassociation inhibitor; GEF, guanine nucleotide exchange factor; WWTR1, WW domain containing transcription regulator 1.