| Name | Initial Conc. (uM) td> | Volume (fL) | Buffered |
1 | Internal_L.PDGFR | 0 | 1000 | No |
| The internalized PDGFR is treated as a generic pool in equilibrium with the surface receptor. This simplifies the turnover processes but fits reasonably well with data. |
2 | L.PDGFR | 0 | 1000 | No |
| This is terribly simplified: there are many interesting intermediate stages, including dimerization and assoc with adapter molecules like Shc, that contribute to the activation of the EGFR. |
3 | PDGF | 0 | 1000 | Yes |
| Platelet-derived growth factor. Heterodimer Mol wt. is approx 30 KDa Deuel et al 1985 Cancer Surv. 4(4):633-53 Conc of 50 ng/ml is close to saturating, and is used by P. Ram (personal communication). Other refs use 65 ng/ml Weise RJ et al 1995 JBC 270(7):3442-3446 A stimulus of 5 min is commonly used. Conversion factor: 1ng/ml = (1e-9/30K)* 1000 Moles/litre = 3e-11M = 3e-5 uM So 50 ng/ml ~ 1.5 nM. |
4 | PDGFR | 0.1083 | 1000 | No |
| Berkers et al JBC 266 say 22K high affinity receptors per cell. Sherrill and Kyte Biochemistry 35 use range 4-200 nM. These values match reasonably. Heidaran et al 1993 JBC 268(13):9287-9295 use NIH3T3 cells and have 6.5e4 receptors/cell. This is also in the same general range. We use this last value because the cell type matches. |
5 | SHC | 0.5 | 1000 | No |
| There are 2 isoforms: 52 KDa and 46 KDa (See Okada et al JBC 270:35 pp 20737 1995). They are acted up on by the EGFR in very similar ways, and apparently both bind Grb2 similarly, so we'll bundle them together here. Sasaoka et al JBC 269:51 pp 32621 1994 show immunoprecs where it looks like there is at least as much Shc as Grb2. So we'll tentatively say there is 1 uM of Shc. |
6 | SHC* | 0 | 1000 | No |
| Phosphorylated form of SHC. Binds to the SoS.Grb2 complex to give the activated GEF form upstream of Ras. |