Quantitative assessment of the p53-Mdm2 feedback loop using protein lysate microarrays.
Mathematical simulations of the p53-Mdm2 feedback loop suggest that both proteins will exhibit impulsive expression characteristics in response to high cellular stress levels. However, little quantitative experimental evaluation has been done, particularly of the phosphorylated forms. To evaluate the mathematical models experimentally, we used lysate microarrays from an isogenic pair of gamma-ray-irradiated cell lysates from HCT116 (p53(+/+) and p53(-/-)). Both p53 and Mdm2 proteins showed expected pulses in the wild type, whereas no pulses were seen in the knockout. Based on experimental observations, we determined model parameters and generated an in silico "knockout," reflecting the experimental data, including phosphorylated proteins.
Ramalingam
Sundhar
S
Molecular Therapeutics Program, National Cancer Institute, NIH, Bethesda, Maryland, USA.
Honkanen
Peter
P
Young
Lynn
L
Shimura
Tsutomu
T
Austin
John
J
Steeg
Patricia S
PS
Nishizuka
Satoshi
S
D045744:Cell Line, Tumor; D025461:Feedback, Physiological; D005786:Gene Expression Regulation; D015972:Gene Expression Regulation, Neoplastic; D016158:Genes, p53; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D008954:Models, Biological; D008962:Models, Theoretical; D010766:Phosphorylation; D040081:Protein Array Analysis / Q000379:methods*; D011518:Proto-Oncogene Proteins / Q000737:chemistry; D051736:Proto-Oncogene Proteins c-mdm2 / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
D011518:Proto-Oncogene Proteins; D016159:Tumor Suppressor Protein p53; D051736:Proto-Oncogene Proteins c-mdm2