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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 asMoleculeSum total ofEnzymeSubstrate of an enzymeProduct of an enzymeSubstrate in ReactionProduct in Reaction
No. of occurrences1130000

Accession and Pathway Details
Accession NameAccession No.Accession TypePathway Link
  • MAPK-bistability
    -fig1c
  • 35Network
    Shared_Object_MAPK-bistability-fig1c Sos PKC 
    MAPK PLA2 Ras 
    PDGFR 
    Model for figure 1c in Bhalla US et al. Science (2002) 297(5583):1018-23.
    The demo for this figure is available here. This synaptic signaling model is without the MKP-1 feedback, so it is bistable and remains so over long periods.

    PKC-active acting as a Molecule in  
    MAPK-bistability-fig1c Network
    NameAccession NamePathway NameInitial Conc.
    (uM)
    Volume
    (fL)
    Buffered
    PKC-active
  • MAPK-bistability
    -fig1c

    Accession No. : 35
  • Shared_Object_
    MAPK-bistability
    -fig1c

    Pathway No. : 179
  • 0.021000No
    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  
    MAPK-bistability-fig1c Network
    Accession NamePathway NameTargetInput
  • MAPK-bistability
    -fig1c

    Accession No. : 35
  • Shared_Object_
    MAPK-bistability
    -fig1c

    Pathway No. : 179
  • PKC-activePKC-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  
    MAPK-bistability-fig1c Network
     Enzyme Molecule /
    Enzyme Activity
    Accession NamePathway NameKm (uM)kcat (s^-1)RatioEnzyme TypeReagents
    1PKC-active /
    PKC-act-raf
  • MAPK-bistability
    -fig1c

    Accession No. : 35
  • Shared_Object_
    MAPK-bistability
    -fig1c

    Pathway No. : 179
  • 66.666744explicit E-S complexSubstrate
    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
    2PKC-active /
    PKC-inact-GAP
  • MAPK-bistability
    -fig1c

    Accession No. : 35
  • Shared_Object_
    MAPK-bistability
    -fig1c

    Pathway No. : 179
  • 66.6667254explicit E-S complexSubstrate
    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.
    3PKC-active /
    PKC-act-GEF
  • MAPK-bistability
    -fig1c

    Accession No. : 35
  • Shared_Object_
    MAPK-bistability
    -fig1c

    Pathway No. : 179
  • 66.666744explicit E-S complexSubstrate
    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.



    Database compilation and code copyright (C) 2022, Upinder S. Bhalla and NCBS/TIFR
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