TIR1 + auxin -> auxinTIR1
auxinTIR1 -> TIR1 + auxin
VENUS + auxinTIR1 -> auxinTIR1VENUS
auxinTIR1VENUS -> VENUS + auxinTIR1
auxinTIR1VENUS -> auxinTIR1
0 -> auxin
auxin -> 0
0 -> VENUS
VENUS -> 0