Explain the importance of understanding how g-protein coupled receptors work. Ex

Question

Explain the importance of understanding how g-protein coupled receptors work.

Explain the link between receptor tyrosine kinase, the HER2 gene, and breast cancer.

Explain what is meant by cellular response, provide an example.

Explain the role of phosphatases in signal deactivation.

Explain why apoptosis is important for multicellular organisms.

Explain how apoptosis can be initiated inside a cell.

If a cell lacked the ability to undergo apoptosis, what are some of the consequences?

What is meant by signal crosstalk?

Explain the importance of studying unicellular yeast cells for understanding the evolution of cell signaling.

Explanation / Answer

1. GPCRs are involved in a wide variety of physiological processes. Some examples of their physiological roles include:

2. The ErbB family is composed of four plasma membrane-bound receptor tyrosine kinases, the other members beingepidermal growth factor receptor, erbB-3 (neuregulin-binding; lacks kinase domain), and erbB-4. All four contain an extracellular ligand binding domain, a transmembrane domain, and an intracellular domain that can interact with a multitude of signaling molecules and exhibit both ligand-dependent and ligand-independent activity. HER2 can heterodimerise with any of the other three receptors and is considered to be the preferred dimerisation partner of the other ErbB receptors.

3. Cellular response is the end of the line for a signal brought to the target cell by a signaling molecule. Once the signal has gone through transduction in the target cell, it is is now ready to be put into action as a cellular response. There are so many different types of responses that we just can't list them all here. But some of the major ones include regulation of protein synthesis and activity as well as cell division, shape, and growth.

4. If a protein is phosphorylated by a kinase, the phosphate group must eventually be removed by a phosphatase through hydrolysis. If it wasn't, the phosphorylated protein would be in a constant state of either being activated or inhibited. Kinases and phosphatases regulate all aspects of cellular function. Some people estimate that 1-2% of the entire genome may encode kinases and phosphatases.  There appears to be about 518 different protein kinases in humans.

5. The cells of a multicellular organism are members of a highly organized community. The number of cells in this community is tightly regulated—not simply by controlling the rate of cell division, but also by controlling the rate of cell death. If cells are no longer needed, they commit suicide by activating an intracellular death program. This process is therefore called programmed cell death, although it is more commonly called apoptosis.

6.  A cell initiates intracellular apoptotic signaling in response to a stress, which may bring about cell suicide. The binding of nuclear receptors by glucocorticoids,heat,radiation,nutrient deprivation,viral infection,hypoxia and increased intracellularcalcium concentration,for example, by damage to the membrane, can all trigger the release of intracellular apoptotic signals by a damaged cell. A number of cellular components, such as poly ADP ribose polymerase, may also help regulate apoptosis.

7. Inhibition of apoptosis can result in a number of cancers, autoimmune diseases, inflammatory diseases, and viral infections. It was originally believed that the associated accumulation of cells was due to an increase in cellular proliferation, but it is now known that it is also due to a decrease in cell death. The most common of these diseases is cancer, the disease of excessive cellular proliferation, which is often characterized by an overexpression of IAP family members. As a result, the malignant cells experience an abnormal response to apoptosis induction: Cycle-regulating genes (such as p53, ras or c-myc) are mutated or inactivated in diseased cells, and further genes (such as bcl-2) also modify their expression in tumors.

8. Cell signaling has been most extensively studied in the context of human diseases and signaling between cells of a single organism. However, cell signaling may also occur between the cells of two different organisms. In many mammals, early embryo cells exchange signals with cells of the uterus.In the human gastrointestinal tract, bacteria exchange signals with each other and with human epithelialand immune system cells.For the yeast Saccharomyces cerevisiae during mating, some cells send a peptide signal (mating factorpheromones) into their environment. The mating factor peptide may bind to a cell surface receptor on other yeast cells and induce them to prepare for mating

Related Questions

Navigate

• Browse (All)
• Browse E
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.