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bioRxiv · 10.1101/2022.01.15.476372

Structural Basis for the Calmodulin-Mediated Activation of eEF-2K

Piserchio, A.·Isiroho, E. A.·Long, K.·Bohanon, A. L.·Kumar, E. A.·Will, N.·Jeruzalmi, D.·Dalby, K. N.·Ghose, R.
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Abstract

Translation is a highly energy consumptive process1 tightly regulated for optimal protein quality2 and adaptation to energy and nutrient availability. A key facilitator of this process is the -kinase eEF-2K that specifically phosphorylates the GTP-dependent translocase eEF-2, thereby reducing its affinity for the ribosome and suppressing the elongation phase of protein synthesis3,4. eEF-2K activation requires calmodulin binding and auto-phosphorylation at the primary stimulatory site, T348. Biochemical studies have predicted that calmodulin activates eEF-2K through a unique allosteric process5 mechanistically distinct from other calmodulin-dependent kinases6. Here we resolve the atomic details of this mechanism through a 2.3 [A] crystal structure of the heterodimeric complex of calmodulin with the functional core of eEF-2K (eEF-2KTR). This structure, which represents the activated T348-phosphorylated state of eEF-2KTR, highlights how through an intimate association with the calmodulin C-lobe, the kinase creates a "spine" that extends from its N-terminal calmodulin-targeting motif through a conserved regulatory element to its active site. Modification of key spine residues has deleterious functional consequences.

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Piserchio, A., Isiroho, E. A., Long, K., Bohanon, A. L., Kumar, E. A., Will, N., Jeruzalmi, D., Dalby, K. N., Ghose, R.. 2022-01-15. Structural Basis for the Calmodulin-Mediated Activation of eEF-2K. https://doi.org/10.1101/2022.01.15.476372

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