A Bitopic Miniprotein Regulates a Membrane-Embedded Enzyme via Topological Allostery

Weber, D. K.; Hernandez, M. S.; Reddy, V. U.; Wang, S.; Larsen, E. K.; Tata, G.; Gustavsson, M.; Cornea, R. L.; Thomas, D. D.; De Simone, A.; Veglia, G.

doi:10.1101/2020.08.28.271940

bioRxiv · 10.1101/2020.08.28.271940

A Bitopic Miniprotein Regulates a Membrane-Embedded Enzyme via Topological Allostery

Weber, D. K.·Hernandez, M. S.·Reddy, V. U.·Wang, S.·Larsen, E. K.·Tata, G.·Gustavsson, M.·Cornea, R. L.·Thomas, D. D.·De Simone, A.·Veglia, G.

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Abstract

Phospholamban (PLN) is a mini-membrane protein that directly controls the cardiac Ca2+-transport response to {beta}-adrenergic stimulation, thus modulating cardiac output during the fight- or-flight response. In the sarcoplasmic reticulum membrane, PLN binds to the sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA), keeping this enzymes function within a narrow physiological window. PLN phosphorylation by cAMP-dependent protein kinase A or increase in Ca2+ concentration reverses the inhibitory effects through an unknown mechanism. Using oriented-sample solid-state NMR spectroscopy and replica-averaged NMR-restrained structural refinement, we reveal that phosphorylation of PLNs cytoplasmic regulatory domain signals the disruption of several inhibitory contacts at the transmembrane binding interface of the SERCA-PLN complex that are propagated to the enzymes active site, augmenting Ca2+ transport. Our findings address long-standing questions about SERCA regulation, epitomizing a signal transduction mechanism operated by posttranslationally-modified bitopic membrane proteins.

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Weber, D. K., Hernandez, M. S., Reddy, V. U., Wang, S., Larsen, E. K., Tata, G., Gustavsson, M., Cornea, R. L., Thomas, D. D., De Simone, A., Veglia, G.. 2020-08-28. A Bitopic Miniprotein Regulates a Membrane-Embedded Enzyme via Topological Allostery. https://doi.org/10.1101/2020.08.28.271940

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