1. Extracellular Environment

2. Extracellular Environment

3. GRB2 SOS Ras Erk P Growth Factor Receptor Tyrosine Kinase Erk Mek Raf MAP Kinase cascade GTP Gene Expression GRB2 SOS Ras Erk P Growth Factor Receptor Tyrosine Kinase Erk Mek Raf MAP Kinase cascade GDP Gene Expression GAP GTP GAP GDP Receptor Tyrosine Kinase

4. GRB2 SOS Extracellular Environment Cytoplasm Nucleus GAP GDP Erk Mek Raf MAP Kinase cascade Ras Receptor Tyrosine Kinase

5. GRB2 SOS Gene Expression Extracellular Environment Cytoplasm Nucleus Erk P Receptor Tyrosine Kinase Erk Mek Raf MAP Kinase cascade Ras GTP P Receptor Tyrosine Kinase P P P P Growth Factor