Exam 8: Cell Signaling Systems

Endosomal fractions can be isolated from cells using differential centrifugation.Using this technique,would you expect to find more or fewer -adrenergic receptors in the purified endosomes in a wild-type liver cell that had been stimulated with glucagon OR in a mutant liver cells that lacks -adrenergic receptor kinase that had been stimulated with glucagon? In explaining your answer describe the role of -adrenergic receptor kinase.

An inhibitor of PTEN is accidentally ingested by an infant.The infant displays symptoms of hypoglycemia.How would inhibiting PTEN lead to this outcome?

First messengers,but NOT second messengers

Oncogenic Ras protein chronically stimulates the MAP kinase pathway.Why is Ras not inactivated in this situation?

Cultures of two different cell types are exposed to the same signaling ligand.Analysis of gene expression shows that only one of the cell types responded to the ligand.Which of the following may account for this difference?

Below is shown the structure of a homodimer of the GR DNA-binding domain.Four areas are highlighted.Which is most likely to interact with DNA?

Predict how the flux of glucose through glucose transporters will change when PI-3K is activated.

Consider a mutant cell that does not form DISC on TNF signaling.Which of the following would occur in this mutant cell if exposed to TNF- ?

Differentiate between the caspase in the apoptotic pathway that is activated by autocleavage and the caspase that is activated by another enzyme.Clearly name each caspase.

Which of the following occurs after activation of the PI-3K signaling pathway?

Which of the following is a metabolite receptor?

Muscle relaxation in response to nitric oxide would be reduced if a(n)__________ was present.

The __________ domain functions as a protein-protein interaction module and is located in the cytoplasmic tail of TNF receptors.

Compare and contrast the pseudosubstrate found in the regulatory subunit of protein kinase A with a substrate of protein kinase A.

Illustrate how a conformational change is critical in the two-step model of EGF function.

Below is shown a short sequence of a protein.Which of the following domains would most likely bind this sequence?

If protein kinase A is activated in a liver cell in response to glucagon binding to the 2-adrenergic receptor,which of the following will result?

What is a protein that promotes GDP-GTP exchange in G proteins known as?

Outline the steps that occur in the shared pathway of glucagon and epinephrine signaling in a liver cell.Include the specific receptors,G protein subunits,upstream signaling protein,and second messengers.

The ligands for metabolite receptors are often derived from dietary nutrients,including all EXCEPT which of the following?