Table 4. The phosphorylation and protein amount of ErbB receptors and the heterodimers in fetal rat fibroblasts and type II cells in response to a 24 hours treatment with conditioned medium from opposite cell type.
Receptor protein values are percentage of treatment signals over control. Phosphorylation values represent proportion of phosphorylated signal over total receptor protein normalized to the experimental control.
| Dimers | ErbB1 | ErbB2 | ErbB3 | ErbB4 | ||||
|---|---|---|---|---|---|---|---|---|
| IP | Ptyr | protein | Ptyr | protein | Ptyr | protein | Ptyr | protein |
| Fibroblasts | ||||||||
| ErbB1 | 170±36 | 77±7# | 118±27 | 87±13 | ||||
| ErbB2 | 137±35 | 65±21# | 112±57 | 106±12 | ||||
| ErbB3 | 96±14 | 126±26 | 171±74 | 114±19 | ||||
| ErbB4 | 80±18 | 112±41 | ||||||
| Type II cells | ||||||||
| ErbB1 | 86±10 | 167±12# | 292±130 | 111±11 | 126±25 | 107±8 | ||
| ErbB2 | 86±2 | 116±12 | 76±3* | 139±10 | ||||
| ErbB3 | 119±16 | 102±14 | 119±16 | 99±7 | 127±44 | 106±15 | ||
| ErbB4 | 81±19 | 204±10# | 110±41 | 139±10 | ||||
Data are Mean±SEM, N=3–5;
*
P<0.05 compared to unstimulated control with Dunnett multiple comparison test (to correct for using controls for 4 treatment corrections).
#
P<0.05 compared to unstimulated control with paired t test. Ptyr: Phosphotyrosine.