Modeling of phyB-dimers(indicates that PfrPfr homodimers are the dominant signalling components)

Filippo Venezia

Diplom biologist (t.o.)

ZBSA

Superviser: Dr. Fleck

Prof. Schaefer

Dimer model

k2 =

€

σ fr N

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σ rk1 = N Photo-conversion rate

ks = synthesis

kdr,fdr = degradation kr = dark

reversion

Pfr-Pfr - D2

Pfr-Pr - D1

Pr-Pr - D0

Simplified phyB pool dimer model

New unknown parameters: k3*, k4

*, kr*

Which are the physiological

functional pool?

Which effects have the new unknown parameters on the

system?

Model selection

Poolkombination:

RSS X2 AIC BIC F-test

D2ns + D2n 0.0613 0.09 -57.26 -59.67 1.083D1ns + D1n 0.972 3.563 -27.25 -29.66 1.81D1+ D2 0.0895 0.128 -53.15 -55.56

1.118 (Pfr-Pool)

f0.9=1.69

Pfr totalPfr-Pfr

n=20

Red = 699nmIndigo = 692nmBlack = 687nmBlue = 681nmGreen = 672nm

Approximation to dark reversion experimental data

Identificable Parameter

kr = 1.5333

krr = 0.0989

X2 = 0.0158

kr/krr = 15.5

n=10

Indigo = OhrGFP/A-B-Blue = ABO/A- on iceRed = calc. Without dark reversionBlack = fitted with dark reversionGreen = ABO/A-

Approximation without speckles

Model without speckles cannot fit the data

Red = 699nmIndigo = 692nmBlack = 687nmBlue = 681nmGreen = 672nm

Summary Dimer model can describe photon-flux response curve sufficiently

The optimal Model explaining Pfr-Pfr homodimer data is obtained through the use of selection methods.

Speckles are essential for stabilizing dark reversion

phyB dimers shows individual dark reversion kinetics.