A mutated form of the a subunit of the heterotrimeric G protein has been identified. It is found to readily exchange GDP for GTP even the absence of an activated receptor. a. What would be the effect on a signaling pathway containing the mutated protein? And in light of your answer would this protein more likely to function as an oncogene or as a tumor suppressor. Briefly explain your answer. b. A paper finds an interesting study where an analog of GTP (GTPYS, guanosine 5'-0-[gamma-thio]triphosphate) is used to alter G-protein to activity. The authors claim that the data below suggest that it could perhaps be used as a treatment for patients with the mutated a subunit as described above. What do you think? [PJ GTPYS Rate of Hydrolysis Hill GTP III GTPYS Time

propose three festurs of a model to connect the genetic mutation you oredicted with the activity of a signaling pathway involving the LDS2B gene product

Practice ques tion 1A Mutations in the signalling pathways depicted above have been associated with an increased incidence of several types of cancer. Which of the below mutations (#1-5) could potentially cause cancer in an individual? Be sure to explain why. Info: In many mammalian species, including humans, there is a hormone (H) that acts as a key regulator of hexose (6 carbon sugar, eg - glucose) metabolism, cell cycle progression, and ultimately cell survival. Hormone H regulates these effects via its receptors which are found at both the cell surface (csRu) and within the cell (icRu). The signalling pathways that become activated in the presence of hormone H are depicted and described below. hormone Signalling via the cell surface receptor Hormone H mediates its cell cycle stimulatory and pro-survival effects by binding to and activating the cell surface hormone H receptor (csRu). · The activated csBH activates Lyn, which activates RAS and ultimately the Raf/MEK/ERK kinase…

When Hedgehog binds to Patched, this not only activates the signaling pathway but alsoactivates the receptor-mediated endocytosis of Patched, so there is less Patched on the plasmamembrane to inhibit Smoothened. a. Outline the steps of receptor-mediated endocytosis, including the roles for each proteininvolved. Hint: if your answer does not include the protein dynamin, you are notproviding enough detail. b. What will happen to Patched after it enters the cell via receptor-mediated endocytosis?Assume that Patched is not recycled back to the plasma membrane.

Which of the following modifications of the Epithelial Growth Factor Receptor (EGFR) would be proliferative of epithelial cells? multiple answers    A. Mutation of active site residue responsible for tyrosine phosphorylation.   B. Deletion of extracellular ectodomain   C. Mutation in ectodomain that prevents binding of EGF   D. Cell expresses EGF   E. Mutation in promoter that increases expression of EGF receptor   F. Dimerization of receptor without growth factor   G. Mutation in EGFR promoter that decreases expression of receptor

The NFAT family is a ubiquitous family of transcription factors. a. Under resting conditions, where is NFAT localized in a cell?  b. Under activated conditions, where is NFAT localized in a cell? c. How is it released from its resting condition and permitted to relocalize? d. Immunosuppressant drugs such as cyclosporin act via inhibition of the calcineurin phosphatase. If NFAT is ubiqitous, how do you think these drugs might act with so few side effects on other signaling processes within the body?

Mutant tyrosine kinase signaling proteins are implicated in many types of human cancer. Hundreds of millions of dollars are required for the basic research and development of a new drug. Tyrosine kinase inhibitor drugs have been approved for cancer treatments by the U.S. Food and Drug Administration. What do you think would be some of the difficulties of finding these drugs given that similar kinases are active in normal cells? Do you think new medications of this type should be developed through government-sponsored research? Why or why not? If not, what alternatives do you propose?

Select from the drop-down menu which type of regulation is occurring in each case. The Ixb12 gene sequence is in a region of condensed chromatin in fetal heart cells, but in adult heart cells, this region is uncondensed. This is an example of choose your answer... regulation. The Ixb12 protein is activated by a kinase, which is an example of choose your answer... regulation. Trx25 mRNA is targeted for degradation by a protein that is present in liver cells but not in heart cells, which is an example of regulation. The Trx25 protein is inactivated by a protein that removes its phosphorylated residues, which is an example of choose your answer... choose your answer... regulation.

A current focus of molecular medicine is to trigger or promote apoptosis of specific cells. several components of the apoptotic pathways are being targeted using this approach. for following, state specifically how the treatment would be expected to stimulate or inhibit apoptosis.    c. Treatment of cells with organic compounds that enter the cell and bind with high affinity to the active site of Caspase-3

A current focus of molecular medicine is to trigger or promote apoptosis of specific cells. several components of the apoptotic pathways are being targeted using this approach. for each of the following, state specifically how the treatment would be expected to stimulate or inhbit apoptosis.   b. exposing cells to recombinant TRAIL protein, a ligand for thr tumor necrosis factor family of receptors