TABLE 1.
List of species in the EGF receptor signaling model
| Receptor forms | |
|---|---|
| R | Unbound/free receptor |
| Ra | Ligand bound receptor, monomer |
| R2 | Ligand bound, dimerized receptor |
| RP | Phosphorylated receptor dimer |
| R-PL | RP associated with PLC-γ |
| R-PLP | R-PL where PLC-γ is phosphorylated |
| R-Sh | RP bound by Shc |
| R-ShP | R-Sh where Shc is phosphorylated |
| R-Sh-G | R-ShP bound by Grb2 |
| R-Sh-G-S | R-Sh-G bound by SOS |
| R-G | RP bound by Grb2 |
| R-G-S | R-G bound by SOS |
| Other molecular species* | |
| L | Ligand |
| Shc | Shc |
| ShP | Phosphorylated Shc |
| Grb | Grb2 |
| SOS | Sos |
| PLCγ | PLC-γ |
| PLCγP | Phosphorylated PLC-γ |
| PLCγP-I | Cytoskeleton bound, inactivated PLCγP |
| G-S | Grb2:SOS complex |
| Sh-G | ShP:Grb2 complex |
| Sh-G-S | ShP:Grb2:SOS complex |
*
The adaptor proteins Shc and Grb2 bind to the cytoplasmic tail of the receptor. Because the cytoplasmic tail of the receptor always faces the cytoplasm, the adaptor proteins (and Sos and PLC-γ) reside only in the cytoplasm. The adaptor proteins, or their complexes, may bind to the receptors that are on the early or late endosomes, but they return back to the cytoplasm when they dissociate from the receptor.