Purine biosynthetic enzymes organize into dynamic cellular bodies called purinosomes. Little is known about the spatiotemporal control of these structures. Using super-resolution microscopy, we demonstrated that purinosomes colocalized with mitochondria, and these results were supported by isolation of purinosome enzymes with mitochondria. Moreover, the number of purinosome-containing cells responded to dysregulation of mitochondrial function and metabolism. To explore the role of intracellular signaling, we performed a kinome screen using a label-free assay and found that mechanistic target of rapamycin (mTOR) influenced purinosome assembly. mTOR inhibition reduced purinosome-mitochondria colocalization and suppressed purinosome formation stimulated by mitochondria dysregulation. Collectively, our data suggest an mTOR-mediated link between purinosomes and mitochondria, and a general means by which mTOR regulates nucleotide metabolism by spatiotemporal control over protein association.
Bibliographical noteFunding Information:
We thank T. Laremore at the Proteomics and Mass Spectrometry Core Facility of the Huck Institutes of the Life Sciences at The Pennsylvania State University for assistance with data collection and analyses. The Orbitrap mass spectrometer was funded by a grant from the Pennsylvania Department of Health Tobacco Settlement Funds. J.B.F. acknowledges the Canadian Institutes of Health Research for fellowship support. This work was funded by the National Institutes of Health grants NIH GM024129 (S.J.B.) and 1R33EB019785-01 (T.J.H. and S.J.B.) as well as the Howard Hughes Medical Institute (X.Z.). J.B.F., S.A.J., Y.F., X.Z., and S.J.B. designed the experiments; J.B.F., S.A.J., H.D., H.H., A.M.P., C.Y.C., D.K., R.J.P., H.Z., and Y.Z. performed the experiments and analyzed the data; J.B.F., S.A.J., A.M.P., R.J.P., and Y.F. prepared the manuscript; J.B.F., Y.F., X.Z., and S.J.B. directed the research; all authors have reviewed and edited the manuscript. The authors declare that they have no competing interests. Additional data reported in this manuscript are available in the supplementary materials.
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