In further studies, cells were either untreated (-) or were induced to overexpre
ID: 217300 • Letter: I
Question
In further studies, cells were either untreated (-) or were induced to overexpress wild-type Ran (WT) or mutant Ran in which a glutamine at residue 69 is replaced with a leucine (Q69L). Ran Q69L hydrolyzes GTP poorly. The nuclear and cytoplasmic fractions are assessed by immunoblotting for the presence of ErbB-2. The amount of Ran and ErbB-2 in the total cell lysates is also shown in Figure (c). (c) Cytoplasmic ErbB-2 WT Q69L Nuclear ErbB-2 WT Q69L Total lysates ErbB-2 WT Q69L Ran ErbB-2 A Ran Ran - - - Importin B1 Importin B1 D D D ErbB-2 ErbB-2 From the data provided, what model can you propose to explain the mechanism by which ErbB-2 is translocated into the nucleus?Explanation / Answer
1. ErbB-2 embedded in plasma membrane.
2. Then, ErbB-2 binds to signal molecule and ErbB-2 are activated
3. ErbB-2’s nuclear location signal (NLS) bind to Importin
4. ErbB2-Importin complex are phosphorylated by Ran protein
5. ErbB-2-Importin complex are activated and ready to move to nucleus
6. Then, ErbB2-Importin complex are in nucleus