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Molecule Parameter List for PKC-active | The statistics table lists the distribution of a molecule acting either as a substrate, product, enzyme or as a molecule within the network.
The text color of a molecule is highlighted by  color. | | Statistics |
| PKC-active participated as | Molecule | Sum total of | Enzyme | Substrate of an enzyme | Product of an enzyme | Substrate in Reaction | Product in Reaction | | No. of occurrences | 1 | 1 | 6 | 0 | 0 | 0 | 0 |
Accession and Pathway Details | |
| Accession Name | Accession No. | Accession Type | Pathway Link | Synaptic_
Network | 16 | Network |
Shared_Object_Synaptic_Network, PKC, PLA2,
PLCbeta, Gq, MAPK,
Ras, EGFR, Sos,
PLC_g, CaMKII, CaM,
PP1, PP2B, PKA,
AC, CaRegulation | This model is an annotated version of the synaptic signaling network.
The primary reference is Bhalla US and Iyengar R. Science (1999) 283(5400):381-7 but several of the model pathways have been updated.
Bhalla US Biophys J. 2002 Aug;83(2):740-52
Bhalla US J Comput Neurosci. 2002 Jul-Aug;13(1):49-62 |
PKC-active acting as a Molecule in Synaptic_Network Network
| Name | Accession Name | Pathway Name | Initial Conc.
(uM) | Volume
(fL) | Buffered | | PKC-active | Synaptic_
Network
Accession No. : 16 | Shared_Object_
Synaptic_
Network
Pathway No. : 70 | 0.02 | 1000 | No | | This is the total active PKC. It is the sum of the respective activities of PKC-basal* PKC-Ca-memb* PKC-DAG-memb* PKC-Ca-AA* PKC-DAG-AA* PKC-AA* I treat PKC here in a two-state manner: Either it is in an active state (any one of the above list) or it is inactive. No matter what combination of stimuli activate the PKC, I treat it as having the same activity. The scaling comes in through the relative amounts of PKC which bind to the respecive stimuli. The justification for this is the mode of action of PKC, which like most Ser/Thr kinases has a kinase domain normally bound to and blocked by a regulatory domain. I assume that all the activators simply free up the kinase domain. A more general model would incorporate a different enzyme activity for each combination of activating inputs, as well as for each substrate. The current model seems to be a decent and much simpler approximation for the available data. One caveat of this way of representing PKC is that the summation procedure assumes that PKC does not saturate with its substrates. If this assumption fails, then the contributing PKC complexes would experience changes in availability which would affect their balance. Given the relatively low percentage of PKC usually activated, and its high throughput as an enzyme, this is a safe assumption under physiological conditions. |
PKC-active acting as a Summed Molecule in Synaptic_Network Network
| Accession Name | Pathway Name | Target | Input | Synaptic_
Network
Accession No. : 16 | Shared_Object_
Synaptic_
Network
Pathway No. : 70 | PKC-active | PKC-DAG-AA*
PKC-Ca-memb*
PKC-Ca-AA*
PKC-DAG-memb*
PKC-basal*
PKC-AA*
| | This is the total active PKC. It is the sum of the respective activities of PKC-basal* PKC-Ca-memb* PKC-DAG-memb* PKC-Ca-AA* PKC-DAG-AA* PKC-AA* I treat PKC here in a two-state manner: Either it is in an active state (any one of the above list) or it is inactive. No matter what combination of stimuli activate the PKC, I treat it as having the same activity. The scaling comes in through the relative amounts of PKC which bind to the respecive stimuli. The justification for this is the mode of action of PKC, which like most Ser/Thr kinases has a kinase domain normally bound to and blocked by a regulatory domain. I assume that all the activators simply free up the kinase domain. A more general model would incorporate a different enzyme activity for each combination of activating inputs, as well as for each substrate. The current model seems to be a decent and much simpler approximation for the available data. One caveat of this way of representing PKC is that the summation procedure assumes that PKC does not saturate with its substrates. If this assumption fails, then the contributing PKC complexes would experience changes in availability which would affect their balance. Given the relatively low percentage of PKC usually activated, and its high throughput as an enzyme, this is a safe assumption under physiological conditions. |
PKC-active acting as an Enzyme in Synaptic_Network Network
| | Enzyme Molecule /
Enzyme Activity | Accession Name | Pathway Name | Km (uM) | kcat (s^-1) | Ratio | Enzyme Type | Reagents | | 1 | PKC-active /
PKC-act-raf
| Synaptic_
Network
Accession No. : 16 | Shared_Object_
Synaptic_
Network
Pathway No. : 70 | 66.6667 | 4 | 4 | explicit E-S complex | Substrate
craf-1
Product
craf-1*
| | | Rate consts from Chen et al Biochem 32, 1032 (1993) k3 = 4 Km for this substrate is trickier. Specific substrates are in the uM range, so we use a higher Km here. This may be too conservative in which case PKC would have a still higher effect on raf. The presence of this phosphorylation and activation step is from Kolch et al 1993 Nature 364:249 | | 2 | PKC-active /
PKC-inact-GAP
| Synaptic_
Network
Accession No. : 16 | Shared_Object_
Synaptic_
Network
Pathway No. : 70 | 3.33333 | 4 | 4 | explicit E-S complex | Substrate
GAP
Product
GAP*
| | | Rate consts are PKC generic rates. This reaction inactivates GAP. The reaction is from the Boguski and McCormick 1993 review in Nature 366:643-654 The phosphorylation Vmax is 6x higher to account for balance of GDP-Ras:GDP-Ras. | | 3 | PKC-active /
PKC-act-GEF
| Synaptic_
Network
Accession No. : 16 | Shared_Object_
Synaptic_
Network
Pathway No. : 70 | 3.33333 | 4 | 4 | explicit E-S complex | Substrate
inact-GEF
Product
GEF*
| | | Rate constants are generic PKC rates. See Chen et al 1993 Biochem 32:1032 This reaction activates GEF. Gives >= 2X stim of ras, and a 2X stim of MAPK over amount from direct phosph of c-raf. Note that it is a push-pull reaction, and also get effect through phosph and inact of GAPs. | | 4 | PKC-active /
PKC-phosph-neuro
granin
| Synaptic_
Network
Accession No. : 16 | Shared_Object_
Synaptic_
Network
Pathway No. : 70 | 28.6275 | 0.58 | 4.03448 | explicit E-S complex | Substrate
neurogranin
Product
neurogranin*
| | | Rates from Huang et al ABB 305:2 570-580 1993 | | 5 | PKC-active /
PKC-phosph-ng-Ca
M
| Synaptic_
Network
Accession No. : 16 | Shared_Object_
Synaptic_
Network
Pathway No. : 70 | 28.5948 | 0.35 | 4 | explicit E-S complex | Substrate
neurogranin-CaM
Product
CaM
neurogranin*
| | | Rates are 60% those of PKC-phosph-neurogranin. See Huang et al ABB 305:2 570-580 1993 | | 6 | PKC-active /
phosph-AC2
| Synaptic_
Network
Accession No. : 16 | Shared_Object_
Synaptic_
Network
Pathway No. : 70 | 33.3333 | 4 | 4 | explicit E-S complex | Substrate
AC2
Product
AC2*
| | | Phorbol esters have little effect on AC1 or on the Gs-stimulation of AC2. So in this model we are only dealing with the increase in basal activation of AC2 induced by PKC k1 = 1.66e-6 k2 = 16 k3 =4 |
| Database compilation and code copyright (C) 2022, Upinder S. Bhalla and NCBS/TIFR
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