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View submission: Does The Endoplasmic Reticulum Transport ATP?
this isn't entirely accurate. So firstly, ATP isn't just made as needed. This is generally a property of substances that experience a "product sink" or are rate-limiting which is generally correlated with an unfavorable free energy for the reaction. ATP does not fall into this category.
Generally, ATP floats around at, what is thought to be, a typically homogeneous concentration throughout the cell. If ATP was made as needed then its synthesis would be the rate-limiting step in processes like muscular contraction. Its not.
ATP increases within the lumen of the endoplasmic reticulum upon intracellular Ca2+ release
That's the title of the article. They use a flourescent ATP sensor that its genetically engineered to locate in the ER. They show that ATP can be pumped into the ER and this can be triggered by Ca2+ signaling activity. Which makes sense, as its known to cost ATP in order to sequester calcium in the ER. So more signaling needs more energy and the cell regulates transport into the ER accordingly.
Generally ATP is thought to travel by diffusion, facillitated across membranes and simple Brownian motion in the cyto/nucleoplasm. However, I encourage anyone to post a study that shows any exceptions, because that would be really interesting.
P.s. in case you were wondering and don't want to read the paper. They showed that the increase in ER ATP concentration was independent of calcium triggering increased ATP synthesis.
There's nothing here!