Figure 4

HTLV-1 and apoptotic signaling pathways. A) The HTLV-1 viral genome. The genome consists of a single- positive strand of RNA. The long terminal repeats (LTRs) flank the ORF (boxes) of the structural (orange, red, yellow and pink) and the nonstructural (blue, green) viral proteins. B) Main death pathways controlled by HTLV-1 proteins. In infected cells receptor-mediated death (through CD95/Fas) is inhibited by a Tax/NF-kB-mediated upregulation of c-FLIP and IAPs. The PI3K-AKT pathway, also activated by Tax, acts by inhibiting the pro-apoptotic protein Bad and by activating the NF-kB pathway. The accessory proteins, p12 and p13, regulate Bcl-2 and caspases 3 and 9, and also ROS production by mitochondria.