'Changed Ras/PI3K interaction.  In Chen Sorger model, PI3K could
activate Ras-GDP-->Ras-GTP.  From literature (example Castellano 2011),
it appears that the opposite actually happens (Ras-GTP can activate the
catalytic function of PI3K). The model has been changed to reflect this.  
The unneeded site 'act' has also been removed from Ras.  Species have
not been carefully checked yet.  Species: 1155.  Parameters: 228.'