“…The signaling pathways activated by ETs are still controversial, with reports pointing to the participation of a G i protein (Imokawa et al, 1996(Imokawa et al, , 1997(Imokawa et al, , 2000, cAMP and PKA (Imokawa et al, 1996(Imokawa et al, , 1997, IP 3 (Kang et al, 1998;Kolch et al, 1993;Yada et al, 1991), Ca 2þ rise (Imokawa et al, 1997;Kang et al, 1998;Kobayashi et al, 2002;Yada et al, 1991), PKC (Imokawa et al, 1996(Imokawa et al, , 1997(Imokawa et al, , 2000, PLC (Imokawa et al, 2000;Kang et al, 1998), and MAPKs (Chen et al, 2007;Imokawa et al, 1996Imokawa et al, , 2000. PKC can phosphorylate and directly activate Raf-1 (Cacace et al, 1996;Kolch et al, 1993;Ueffing et al, 1997), which is one of the components of the MAPK signaling pathway.…”