You purify a protein (a single polypeptide). You produce a monoclonal antibody against your protein and a polyclonal antibody against your protein. You wish to use these two antibodies to determine where in the cell your protein is localized by immune-fluorescence microscopy. Since you've just started working on your protein, you don't know many of its properties, such as whether it acts as a monomer, homodimer, heterodimer, or is part of a larger protein complex. You carry out your experiment and discover that the polyclonal antibody gives a strong signal at or near the plasma membrane and nowhere else. In contrast, your monoclonal antibody gives does not give you any signal. Assuming your protein was not denatured during purification, and that both antibodies are fully functional in your experiment- where do you think your protein localizes, why do your antibodies give you different results, and what do these results suggest about your protein? Assume the results above were for cultured cells that had been incubated for some time in the absence of growth factors (assume this does not trigger apoptosis). You now add a particular growth factor. Two hours later you repeat your immune-fluorescence experiment and find that both the monoclonal antibody and the polyclonal antibody give you signal throughout the cytoplasm. What conclusions and possibilities does this suggest about your protein?
You purify a protein (a single polypeptide). You produce a monoclonal antibody against your protein and a polyclonal antibody against your protein. You wish to use these two antibodies to determine where in the cell your protein is localized by immune-fluorescence microscopy. Since you've just started working on your protein, you don't know many of its properties, such as whether it acts as a monomer, homodimer, heterodimer, or is part of a larger protein complex. You carry out your experiment and discover that the polyclonal antibody gives a strong signal at or near the plasma membrane and nowhere else. In contrast, your monoclonal antibody gives does not give you any signal. Assuming your protein was not denatured during purification, and that both antibodies are fully functional in your experiment- where do you think your protein localizes, why do your antibodies give you different results, and what do these results suggest about your protein? Assume the results above were for cultured cells that had been incubated for some time in the absence of growth factors (assume this does not trigger apoptosis). You now add a particular growth factor. Two hours later you repeat your immune-fluorescence experiment and find that both the monoclonal antibody and the polyclonal antibody give you signal throughout the cytoplasm. What conclusions and possibilities does this suggest about your protein?
