Table 1. Equations for minimal PI(4,5)P... | Rockefeller University Press

Table 1.

Equations for minimal PI(4,5)P₂–DAG reaction scheme

Equation	No.
$d {[PI (4, 5) P_{2}]}_{local} = d {[PI (4, 5) P_{2}]}_{local} - d {[PI (4, 5) P_{2}]}_{local} \cdot k_{i (t)} \cdot {De}_{f (t)} \cdot dt$	6
$d [DAG] = d [DAG] + d {[PI (4, 5) P_{2}]}_{tot} \cdot k_{i (t)} \cdot {De}_{f (t)} \cdot dt - d [DAG] \cdot k_{ii} \cdot dt$	7
$d [{IP}_{3}] = d [{IP}_{3}] + d {[PI (4, 5) P_{2}]}_{tot} \cdot k_{i (t)} \cdot {De}_{f (t)} \cdot dt - d [{IP}_{3}] \cdot k_{v} \cdot dt$	8
$\begin{array}{l} {De}_{f (t)} = 1 - (Rd_f \cdot exp (- τ_{rd}) / t) + Sd_f \cdot exp (- τ_{sd} / t) \\ Rd_f : fraction of rapid desensitization \\ Sd_f : fraction of slow desensitization \\ τ_{rd} : time constant for the rapid desensitization \\ τ_{sd} : time constant for the slow desensitization \end{array}$	9
$\begin{array}{l} k_{i (t)} = k_{i} \cdot {B_PLC}^{pg • t} \\ B_PLC : basal PLC activity \\ pg : power parameter of G_{q} PCR receptor stimulation \end{array}$	10
$d [PA] = d [PA] + d [DAG] \cdot k_{ii} \cdot dt - d [PA] \cdot k_{iii} \cdot dt$	11
$d [PI (4) P] = d [PI (4) P] + d [PA] \cdot k_{iii} \cdot dt - d [PI (4) P] \cdot k_{iv} \cdot dt$	12
$d {[PI (4, 5) P_{2}]}_{recovered} = d [PI (4) P] \cdot k_{iv} \cdot dt - d {[PI (4, 5) P_{2}]}_{recovered} \cdot k_{i (t)} \cdot {De}_{f (t)} \cdot dt$	13
$\begin{array}{l} d {[PI (4, 5) P_{2}]}_{global} = d {[PI (4, 5) P_{2}]}_{global} - d {[PI (4, 5) P_{2}]}_{global} \cdot k_{i_g (t)} \cdot {De}_{f (t)} \cdot dt \\ k_{i_g} : rate constant for global PLC activity \end{array}$	14
$\begin{array}{l} d {[PI (4, 5) P_{2}]}_{diffused_in} = (d {[PI (4, 5) P_{2}]}_{global} - d {[PI (4, 5) P_{2}]}_{local}) \\ \cdot (1 - errf (spot / sprt (4 \cdot dcoef \cdot dt))) - d {[PI (4, 5) P_{2}]}_{diffused_in} \cdot k_{i (t)} \cdot {De}_{f (t)} \cdot dt \\ errf : error function \\ dcoef : diffusion coefficient of PI (4, 5) P_{2} \\ spot : distance between local and global domain \end{array}$	15
$\begin{array}{l} d {[PI (4, 5) P_{2}]}_{scavenged_PHd} = (d {[PHd]}_{rel} - d {[PHd]}_{IP3}) \cdot (1 / (1 + K_{d,PHd} / (d {[PI (4, 5) P_{2}]}_{local} \\ + d {[PI (4, 5) P_{2}]}_{recovered} + d {[PI (4, 5) P_{2}]}_{diffused_in}))) \end{array}$	16
$d {[PI (4, 5) P_{2}]}_{tot} = d {[PI (4, 5) P_{2}]}_{local} + d {[PI (4, 5) P_{2}]}_{recovered} + d {[PI (4, 5) P_{2}]}_{diffused_in} - d {[PI (4, 5) P_{2}]}_{scavenged_PHd}$	17