A scientist is running an experiment to determine the impacts of a new drug top top cells. Aftering dealing with cells through the drug, the scientist observes an increase in the lot of diacylglycerol found within these cells. Based upon this information, what kind of receptor is this medicine likely communicating with?


The observed boost in diacylglycerol (DAG) is indicative that the activation of a GProtein-Coupled Receptor (GPCR).

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Upon binding that a ligand come a GPCR, a conformational change in the receptor is transmitted come a G protein bound to the cell membrane within the cell. This subsequently reasons the alpha-subunit of the G protein to lose its bound GDP, and in exchange it receives GTP. This, in turn, activates the G protein, resulting in the alpha subunit come dissociate from the beta-gamma subunit. This newly liberated alpha subunit-GTP complex then goes on to activate one more component that the signal transduction cascade. There room two main varieties of GPCR signaling pathways, depending on the form of alpha subunit involved.

cAMP Pathway: when the alpha subunit is stimulatory, denoted as 

, it will certainly activate an enzyme in the plama membrane called adenylyl cylcase. Activation of this enzyme results in the switch of ATP right into cAMP. CAMP, in turn, acts together a second messenger in ~ the cell, activing Protein Kinase A (PKA). This protein kinase climate goes on to phosphorylate number of proteins within the cell, which leads to a response. Furthermore, the G protein may also be inhibitory and also denoted as 
. This alpha subunit basically does opposing of what 
 does. That is, that acts to inhibit adenylyl cyclase, with a succeeding decrease in intracellular level of cAMP and also a palliation in the task of PKA.

Phosphatidylinositol Pathway: In this case, the G protein is denoted as 

. This details G protein walk on to activate an enzyme dubbed phospholipase C (PLC). PLC, in turn, cleaves a details phospholipid within the plasma membrane called phosphatidylinositol-4,5-bisphosphate (
) right into two products, inositol-1,4,5-trisphosphate (
) and diacylglycerol (DAG). 
 dissociates indigenous the membrane and binds to a receptor on the absorbent reticulum, stimulating the release of  into the cytosol. Together, DAG and 
 work with each other to activate Protein Kinase C (PKC), which then goes on come phosphorylate countless proteins within the cell, resulting in a cellular response.

And briefly, receptor tyrosine kinases (RTK) are receptors situated in the plasma membrane. ~ above binding the ligand, RTK"s have two intracellular domains that phosphorylate each other, hence activating the receptor. The RTK then goes top top to cause a signal transduction cascade.

Ionotropic receptor are located in the plasma membrane, and they also serve as ion channels through i beg your pardon ions can flow. Generally, binding that ligand come ionotropic receptors induces a conformational adjust in the receptor that reasons the ion channel come open.

The dihydropyridine receptor (DHP) is situated in the plasma membrane and also is generally connected with another receptor recognized as the ryanodine receptor, located in the membrane the the absorbent reticulum. Generally, the DHP receptor is set off by a change in membrane voltage, and also upon stimulation causes: 1) an influx of  from the extracellular liquid into the cytosol, and 2) is mechanically coupled to the ryanodine receptor, stimulating it come release  from the absorbent reticulum into the cytoplasm.

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And finally, together the surname implies, intracellular receptors are not located in the plasma membrane, however instead located in either the cytosol or nucleus. For a ligand to bind this class of receptor, that must have the ability to diffuse across the plasma membrane to make its method into the cell. Generally, ~ above activation, intracellular receptor-ligand complexes action as transcription factors, directly modulating the task of specific genes by transforming their expression.