eal Chegg Study IGuided solutions and S... Course: BIOL 0350-01 Cell Biology Sp.
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eal Chegg Study IGuided solutions and S... Course: BIOL 0350-01 Cell Biology Sp... https://ilearn.sfsu.edu/ay1415/plugin How could you try to predict where... Favorites 3. A gene regulatory protein, A, is usually found in the cytosol. When the cell is exposed to hormones, protein A moves from the cytosol into the nucleus, where it turns on genes involved in cell division. When you purify protein A from cells that have not been treated with hormones, you find that protein B is always complexed with it. To determine the function of protein B, you engineer cells lacking the gene for protein B. You compare normal and defective cells by separating the nuclear proteins from the cytoplasmic proteins, and then separating the proteins in these fractions by gel electrophoresis. You identify the presence of protein A and protein B by looking for their characteristic bands on a gel. The gel you run is shown below cells lacking protein B normal cel protein A protein B ith hormo without hormone C cytoplasmic fraction N nuclear fraction [To interpret the gel: The experimental conditions are shown above and a legend is given below the gel. Black bars indicate the presence of a protein A or B, and empty spaces indicate the absence of these proteins. For example, the left lane shows both proteins A & B are present in the cytoplasm (C) of normal cells, without hormone 3a. Do you predict that protein A carries a nuclear localization or a nuclear export signal? 3b. Please provide a hypothesis for the function of protein B and how it interacts with protein A and hormone. Please explain your reasoning.Explanation / Answer
3a. Protein a carries localization or a nuclear export signal.
3b. Binding of hormone to receptor initiates a series of events which leads to generation of so-called second messengers within the cell (the hormone is the first messenger). The second messengers then trigger a series of molecular interactions that alter the physiologic state of the cell. Another term used to describe this entire process is signal transduction.
Cyclic adenosine monophosphate (cAMP) is a nucleotide generated from ATP through the action of the enzyme adenylate cyclase. The intracellular concentration of cAMP is increased or decreased by a variety of hormones and such fluctuations affect a variety of cellular processes. One prominent and important effect of elevated concentrations of cAMP is activation of a cAMP-dependent protein kinase called protein kinase A.
Protein kinase A is nominally in an catalytically-inactive state, but becomes active when it binds cAMP. Upon activation, protein kinase A phosphorylates a number of other proteins, many of which are themselves enzymes that are either activated or suppressed by being phosphorylated. Such changes in enzymatic activity within the cell clearly alter its state.
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