Fig. 5.

PAK1 cross regulate multiple signal pathways.

RAS activation directly initiates PAK1, MAPK and PI3K/Akt pathway. PAK1 allocates crosstalk between the PI3K and MAPK pathways. PAK1 can induce MEK1/2 and ERK1/2 activation by RAF and increase PI3K/Akt signaling by PDK1. PAK1 can also activate pro-inflammatory pathways by facilitating nuclear activation of NF-kappa B. In addition, PAK1 facilitates Wnt/β-catenin signaling, make β-catenin accumulate in the cytoplasm and translocate to the nucleus. Moreover, Akt can inhibit β-catenin transfer into nucleus.