Appendix 1—table 2. Protein are specified by the Uniprot identifier (Bairoch et al., 2005) and the corresponding gene ID.

For ions and chemical compounds, the ChEBI (Chemical Entities of Biological Interest Degtyarenko et al., 2008) identifier is used instead. The initial concentrations of all un-phosphorylated species and complexes between proteins were set to 0 pM.

Species	Uniprot ID /	Gene ID	Initial	Source
	ChEBI ID		Concentration
BRI1	O22476	At4g39400	$\mathrm{0.182\hspace{0.17em}633}\mathrm{pM}$	Wilma van Esse et al., 2011
BAK1	Q94F62	At4g33430	$\mathrm{0.099\hspace{0.17em}632}\mathrm{pM}$	Wilma van Esse et al., 2011
BIR3			$\mathrm{0.237\hspace{0.17em}423\hspace{0.17em}11}\mathrm{pM}$	this study
AHA*			$\mathrm{0.232\hspace{0.17em}442}\mathrm{pM}$	$[AHA1]+[AHA2]$
AHA1	P20649	At2g18960	$\mathrm{0.116\hspace{0.17em}221}\mathrm{pM}$	assumption:$\frac{AHA1}{AHA2}\approx \frac{1}{1}$
				mRNA data (eFP Browser)
				Winter et al., 2007
AHA2	P19456	At4g30190	$\mathrm{0.116\hspace{0.17em}221}\mathrm{pM}$	this study
AHA CT*	C-terminus		$\mathrm{0.232\hspace{0.17em}442}\mathrm{pM}$	assumed to be
	of AHAs			$[AHA1]+[AHA2]$
BKI1	Q9FMZ0	At5g42750	$\mathrm{0.219\hspace{0.17em}16}\mathrm{pM}$	assumption:$1.2\cdot {[BRI1]}_{t=0}$
BIK1	O48814	At2g39660	$\mathrm{0.219\hspace{0.17em}16}\mathrm{pM}$	assumption:$1.2\cdot {[BRI1]}_{t=0}$
CNGC10	Q9LNJ0	At1g01340	$0.1\mathrm{pM}$
H+in	24636	-	$\mathrm{63\hspace{0.17em}000}\mathrm{pM}$
H+out	24636	-	fitted to data
K+out	29103	-	9.8425 × 109 pM	½ MS medium
K+in	29103	-	8.4 × 1010 pM	Maathuis and Sanders, 1993
K+vac	29103	-	8.4 × 1010 pM	assumed to be identical to K+in
BL	28277	-	$dose$	see experimental setup

^*To avoid overly complicating the model we have summarized the pump activity of $AHA1$ and $AHA2$ into one reaction that is mediated by $AHA$, which is defined as the sum of $[AHA1]$ and $[AHA2]$. Similarly, regulatory function of the C-terminal regions of the AHAs is mediated by the unphosphorylated form of the C-terminus AHA CT, which represents the C-terminal regions of both $AHA1$ and $AHA2$.