Exam 8: Cell Signaling Systems

Place the following steps in proper order: A. phosphorylation of RTK cytoplasmic tails B. activation of downstream signaling pathways C. ligand binding, receptor dimerization, and kinase activation D. protein binding to RTK phosphotyrosines and phosphorylation of target proteins

Which of the following proteins contains an SH3 domain?

When PKA is inactive, which of the following is true?

Below is a figure of G_{s $\alpha$} protein bound to G _{$\beta$ $\gamma$} protein. What is the name of the portion indicated by the arrow, and which protein is it a part of?

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- $\alpha$ ?

A liver cell is exposed to glucagon and epinephrine and glucose export is monitored. On addition of an adenylate cyclase inhibitor, the level of glucose export is reduced but not eliminated. Propose a reason for this partial reduction.

Ligand binding causes which of the following to form trimers?

A new protein is discovered that contains a pleckstrin homology domain. Which of the following is likely to bind to the protein?

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

Place the following steps of the apoptotic pathway in their proper order. A. CASP3 cleavage of cellular proteins B. Cleavage of procaspase 8 C. Cleavage of procaspase 3 D. Assembly of DD and DED protein complexes

Hsp90 is a type of

Contrast the structures and nucleotide binding properties of G_{s $\alpha$} when interacting with adenylate cyclase versus G _{$\beta$ $\gamma$} protein.

Endosomal fractions can be isolated from cells using differential centrifugation. Using this technique, would you expect to find more or fewer $\beta$ -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 $\beta$ -adrenergic receptor kinase that had been stimulated with glucagon? In explaining your answer describe the role of $\beta$ -adrenergic receptor kinase.

Protein kinase A is immunoprecipitated from two different liver samples. The immunoprecipitate is then analyzed with SDS-PAGE. The first sample shows a single band on the gel, whereas the second displays two bands. Propose an explanation for why the results are different.

Liver cells were monitored for changes in metabolic enzymatic activity after exposure to glucagon. The enzymes that showed changes in activity were then analyzed to assess if they had been covalently modified. Which of the following results were likely observed?

Below is the molecular structure of a single bovine $\beta$ -arrestin subunit. Two locations are indicated. What is most likely to interact with the protein at these locations?

What is the TNF receptor-TRADD-FADD-procaspase 8 adaptor complex also known as?

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?

Removal of which metal ion would likely alter the structure of the GR DNA-binding domain and preclude it from binding to DNA?

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