Question

Cell lines A and B both survive in tissue culture containing serum but do not proliferate. Factor F is known to stimulate proliferation in cell line A. Cell line A produces a receptor protein (R) that cell line B does not produce. To test the role of receptor R, you introduce this receptor protein into cell line B, using recombinant DNA techniques. You then test all of your various cell lines in the presence of serum for their response to factor F, with the results summarized in Table Q16-1.Which of the following cannot be concluded from your results above?

(a) Binding of factor F to its receptor is required for proliferation of cell line A.
(b) Receptor R binds to factor F to induce cell proliferation in cell line A.
(c) Cell line A expresses a receptor for factor F.
(d) Factor F is not required for proliferation in cell line B.

Answer 1

We cannot conclude that (D) 'Factor F is not required for proliferation in cell line B' because the experiment only demonstrates the effect of introducing receptor R into cell line B and does not address the full involvement of factor F in cell line B's cellular mechanisms for proliferation.

Step-by-step explanation:

Based on the information provided about cell signaling pathways, it is clear that cell division is often dependent on external signals, specifically growth factors that bind to cell-surface receptors.

Receptors like receptor tyrosine kinases (RTKs) are integral in initiating cell signaling pathways that lead to cell division, such as the RAS/MAP kinase pathway. In our specific scenario where we introduced receptor R (presumably an RTK) into cell line B and tested the response to factor F, it appears that receptor R is necessary for the response to factor F in cell line A.

However, from the options provided, we cannot conclude "(d) Factor F is not required for proliferation in cell line B" because the experiment only shows the result of adding receptor R to cell line B. This does not provide information on whether factor F alone might affect cell line B, which may lack another component of the proliferative signaling pathway.