What are the two major target types of cAMP?

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What are the two major target types of cAMP?

cAMP acts as a second messenger by engaging two main kinds of effector proteins: protein kinases and ion channels. The most well-known target is protein kinase A (PKA). When cAMP levels rise, it binds to the regulatory subunits of PKA, releasing the catalytic subunits, which then phosphorylate a variety of target proteins. This phosphorylation changes enzyme activities, transport processes, and other signaling events inside the cell, producing the cellular response to the signal. Another key target type is cyclic nucleotide–gated ion channels. cAMP can bind directly to these channels and alter their opening, changing the flow of ions across the membrane, which is especially important in sensory systems like vision and smell. The other options mix upstream signaling components or unrelated enzymes with the actual direct targets. Upstream elements like membrane receptors and G proteins initiate the signal but are not direct targets of cAMP. DNA polymerases, ribosomes, phospholipases, or receptors are not the primary direct effectors of cAMP signaling in the same way as kinases and ion channels.

cAMP acts as a second messenger by engaging two main kinds of effector proteins: protein kinases and ion channels. The most well-known target is protein kinase A (PKA). When cAMP levels rise, it binds to the regulatory subunits of PKA, releasing the catalytic subunits, which then phosphorylate a variety of target proteins. This phosphorylation changes enzyme activities, transport processes, and other signaling events inside the cell, producing the cellular response to the signal.

Another key target type is cyclic nucleotide–gated ion channels. cAMP can bind directly to these channels and alter their opening, changing the flow of ions across the membrane, which is especially important in sensory systems like vision and smell.

The other options mix upstream signaling components or unrelated enzymes with the actual direct targets. Upstream elements like membrane receptors and G proteins initiate the signal but are not direct targets of cAMP. DNA polymerases, ribosomes, phospholipases, or receptors are not the primary direct effectors of cAMP signaling in the same way as kinases and ion channels.

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