active, prevents the cell cycle regulatory protein pGoGi from inducing apoptosis and blocking cell division (Figure 2). Figure 2. Capsaicin-actvated TRPV1 signaling pathway in human cells

several transmembrane domains that ave embedded in the membrane as well as a carbory-terminus and an aminoterminus that are located inside the cell (Figure 1). Outside of the Cell TRPV1 Phospholipid Bilayer Inside of the Cell Figure 1. Structure of the THPVI protein channet in the membrane domains of TRPV1, which epene the ion channel. actire, orevents the cell cycle regulatory protein pGoG from inducing apoptosis and blocking cell division (Figure 2).

(a) Low extracellular pH activates TRPV1 through the binding of H+ ions to TRPV1 . Describe the properties, including the location, of the site of TRPV1 that allow H+ ions to bind. Describe the specific location in the cell where ATF3 protein is produced.

(b) The pGoG protein is known to block the G1 to S transition in the cell cycle. Explain why this prevents mitosis from happening in the cell.

(c) Before treating melanoma cells with capsaicin, researchers pretreated the cells with an inhibitor of calcineurin. Predict the effect of this pretreatment on the ability of capsaicin to induce apoptosis by the pathway shown in Figure 2. Provide reasoning to justify your prediction.

(d) Researchers claim that many cancers include a mutation in the gene encoding pGoG . Support the researchers' claim.