The Integrative Cell Biology Laboratory and The Biophysical Sciences Institute, School of Biological and Biomedical Sciences, Durham University, Durham, UK
Rate law for v6: Transcription of POLARIS gene
v11: Conversion of the activated form of ethylene receptor to its inactivated form
v5: Conversion of auxin receptor from the activated form to the inactivated form
Rate law for v2: Auxin biosynthesis in the cell
vEthylene: Uptake rate of exogenous ACC (1-aminocyclopropane-1-carboxylic acid)
vAuxin: Uptake rate of exogenous auxin (indole-3-acetic acid, IAA)
v14: Conversion of the inactivated form of CTR1 protein to its activated form by Re*
Rate law for v14: Conversion of the inactivated form of CTR1 protein to its activated form by Re*
Rate law for v18: Biosynthesis of cytokinin
Rate law for v3: Auxin removal from the cell
Rate law for v15: Conversion of the activated form of CTR1 protein to its inactivated form
v16: Activation of the downstream of ethylene signalling response is inhibited by CTR1*
Rate law for v17: Removal of the unknown molecule X
v10: Conversion of the inactivated form of ethylene receptor to its activated form by PLSp
v15: Conversion of the activated form of CTR1 protein to its inactivated form
Rate law for v8: Translation of POLARIS gene
vCytokinin: Uptake rate of exogenous cytokinin
Rate law for v9: Decay of protein of POLARIS gene
Rate law for v11: Conversion of the activated form of ethylene receptor to its inactivated form
Rate law for v4: Conversion of auxin receptor from the inactivated form to the activated form
Rate law for v1: Auxin Transport to the cell
This is the single cell model for analysis of hormonal crosstalk in Arabidopsis described in the article: Modelling and experimental analysis of hormonal crosstalk in Arabidopsis. Liu J, Mehdi S, Topping J, Tarkowski P and Lindsey K. Mol Syst Biol. 2010 Jun 8;6:373; PmID: 20531403 , DOI: 10.1038/msb.2010.26 Abstract: An important question in plant biology is how genes influence the crosstalk between hormones to regulate growth. In this study, we model POLARIS (PLS) gene function and crosstalk between auxin, ethylene and cytokinin in Arabidopsis. Experimental evidence suggests that PLS acts on or close to the ethylene receptor ETR1, and a mathematical model describing possible PLS-ethylene pathway interactions is developed, and used to make quantitative predictions about PLS-hormone interactions. Modelling correctly predicts experimental results for the effect of the pls gene mutation on endogenous cytokinin concentration. Modelling also reveals a role for PLS in auxin biosynthesis in addition to a role in auxin transport. The model reproduces available mutants, and with new experimental data provides new insights into how PLS regulates auxin concentration, by controlling the relative contribution of auxin transport and biosynthesis and by integrating auxin, ethylene and cytokinin signalling. Modelling further reveals that a bell-shaped dose-response relationship between endogenous auxin and root length is established via PLS. This combined modelling and experimental analysis provides new insights into the integration of hormonal signals in plants. This model was originally created using Copasi and taken from the supplementary materials of the MSB article. It uses equation 5 for the auxin biosynthesis and was altered to also contain the reactions for ACC, IAA and cytokinine import. Different from the supplementary material, the parameters for the auxin synthesis, v2, are set to k2c = 0.01 uM and k2=0.2 uM_per_sec and for the WT PLS transcription k6=0.3 . To obtain the model described in the first table of the supplementary materials, set k2c=k2=0 and k6=0.9 . For the pls and PLSox mutants, k6 should be set to 0 and 0.45, respectively. This model originates from BioModels Database: A Database of Annotated Published Models. It is copyright (c) 2005-2010 The BioModels Team. For more information see the terms of use . To cite BioModels Database, please use Le Novère N., Bornstein B., Broicher A., Courtot M., Donizelli M., Dharuri H., Li L., Sauro H., Schilstra M., Shapiro B., Snoep J.L., Hucka M. (2006) BioModels Database: A Free, Centralized Database of Curated, Published, Quantitative Kinetic Models of Biochemical and Cellular Systems Nucleic Acids Res., 34: D689-D691.
v4: Conversion of auxin receptor from the inactivated form to the activated form
Rate law for v10: Conversion of the inactivated form of ethylene receptor to its activated form by PLSp
Rate law for v16: Activation of the downstream of ethylene signalling response is inhibited by CTR1*
Rate law for v7: Decay of mRNA of POLARIS gene