TGF-β signaling can inhibit cell entry into the cell division cycle. Describe a mechanism by which mitogen signaling through the PI3K/AKT pathway can counteract the inhibitory effects of TGF-β. Be sure to include the factors involved and the specific events that occur in your answer.

Which of the following mechanisms is LEAST likely to contribute to tumorigenesis driven by the myc oncogene?

Hypermethylation of CpG islands is particularly effective at inactivating tumor suppressor genes when it occurs

This part of the Ras protein interacts with other downstream proteins to transmit a signal when Ras is bound to GTP.

Which of the following types of mutations are MOST likely to be found in cancer cells?

Ligand binding by GPCRs activates what intrinsic receptor activity?

In general terms, briefly indicate several ways in which Notch signaling is different from a receptor tyrosine kinase pathway. There is no need to describe each step in the pathway, focus on the main differences.

Describe the mechanistic role of SOS in the EGF signaling cascade. Be sure to discuss its biochemical activity and the impact of that activity on interacting partners. (one does not need to describe the entire pathway).

Which of the following conditions may contribute to the hyperphosphorylation of pRb?

Cytokine receptors are used by mammalian cells to communicate with their environment. Functionally, cytokine receptors operate much like tyrosine kinase receptors, with some differences. Name two differences.