x1 = Smad2c
x2 = Smad2n
x3 = Smad4c
x4 = Smad4n
x5 = T1R_Surf
x6 = T1R_Cave
x7 = T1R_EE
x8 = T2R_Surf
x9 = T2R_Cave
x10 = T2R_EE
x11 = LRC_Surf
x12 = LRC_Cave
x13 = LRC_EE
x14 = Smads_Complex_c
x15 = Smads_Complex_n
x16 = TGF_beta