Z-DEVD-FMK? The last term gMITF, represents the MITF degradation. The total amount of RSK1 is kept Inhibitors,Modulators,Libraries constant, while its phosphory lation state is dynamically determined by equations and. PIAS3 has a linear degradation. The dynamics of S73 phosphorylated MITF is given in equation Where gMITFp73 is the degradation rate that applies to the ubiquitinated ratio R of the amount of MITFp73. In the dynamics of S409 phosphorylated MITF, simple linear degradation is applied. When MITF is phosphorylated on both sites, the sum of the two degra dation rates applies Further, these four phosphorylation states of MITF bind PIAS3, each with their own association and disso ciation rate Inhibitors,Modulators,Libraries constants, yielding differential equation for PIAS3, for the MITF Inhibitors,Modulators,Libraries PIAS3 complex, for the S73 phosphorylated MITF PIAS3 complex, for the S409 phosphorylated MITF PIAS3 complex and for the double phosphorylated MITF PIAS3 complex.

STAT3 is binding PIAS3 while phosphorylated. The dynamics of the PIAS3 STAT3 complex is given in equation and un phosphorylated and phosphory lated STAT3 in equation and respectively. To represent higher stability by proteins in complexes, the degradation rate of the complex is set to 20% Inhibitors,Modulators,Libraries of the mean of the degradation rates assigned to the constitut ing proteins in un bound form. and B. The term a 1 and has the unit minute and does not affect the calculation, but is needed for the correct unit representation. Part is derived in a similar way Let R be the ratio R after one minute of MITF production.

Then the rate of change Inhibitors,Modulators,Libraries due to this effect is per minute, where MITF activity The readouts of the model are the amounts of the dif ferent phosphorylation and complex states of the pro teins involved. To be able to view this model in the light of available experimental results, these levels have to be interpreted antiangiogenic in a way comparable to the lab gener ated data. The transcriptional activity of MITF and STAT3 is measured either as luciferase activity of a transfected reporter gene or as mRNA levels of down S73 phosphorylated MITF get ubiquitin tagged for degradation by phosphorylated ERK. Introducing another modification site would cause another doubling of the number of state variables representing MITF. To reduce complexity, we chose to represent the ubiquiti nation with one differential equation, describing the ratio R of the total amount of S73 phosphorylated MITF that also is ubiquitinated. The three parts of equation correspond to the three processes altering the ratio R The ubiquitina tion of un ubiquitinated MITF, the ubiquitination dependent degradation of ubiquitinated MITF and the production of new un ubiquitinated MITF.