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A Calcineurin Docking Motif (LXVP) in Dynamin-related Protein 1 Contributes to Mitochondrial Fragmentation and Ischemic Neuronal Injury
Journal article   Open access   Peer reviewed

A Calcineurin Docking Motif (LXVP) in Dynamin-related Protein 1 Contributes to Mitochondrial Fragmentation and Ischemic Neuronal Injury

Andrew M Slupe, Ronald A Merrill, Kyle H Flippo, Mark A Lobas, Jon C. D Houtman and Stefan Strack
The Journal of biological chemistry, Vol.288(17), pp.12353-12365
04/26/2013
DOI: 10.1074/jbc.M113.459677
PMCID: PMC3636919
PMID: 23486469
url
https://doi.org/10.1074/jbc.M113.459677View
Published (Version of record) Open Access

Abstract

Background: The mitochondrial fission enzyme dynamin-related protein 1 (Drp1) is regulated via reversible phosphorylation of Ser-656. Results: The Drp1 L X VP motif mediates dephosphorylation and activation by calcineurin (CaN), which influences mitochondrial morphology and survival post-injury in neurons. Conclusion: The CaN-Drp1 signaling axis can be detrimental to injured neurons. Significance: The CaN-Drp1 complex may be a target for neuroprotective therapeutic intervention. Fission and fusion events dynamically control the shape and function of mitochondria. The activity of the mitochondrial fission enzyme dynamin-related protein 1 (Drp1) is finely tuned by several post-translational modifications. Phosphorylation of Ser-656 by cAMP-dependent protein kinase (PKA) inhibits Drp1, whereas dephosphorylation by a mitochondrial protein phosphatase 2A isoform and the calcium-calmodulin-dependent phosphatase calcineurin (CaN) activates Drp1. Here, we identify a conserved CaN docking site on Drp1, an L X VP motif, which mediates the interaction between the phosphatase and mechanoenzyme. We mutated the L X VP motif in Drp1 to either increase or decrease similarity to the prototypical L X VP motif in the transcription factor NFAT, and assessed stability of the mutant Drp1-CaN complexes by affinity precipitation and isothermal titration calorimetry. Furthermore, we quantified effects of L X VP mutations on Drp1 dephosphorylation kinetics in vitro and in intact cells. With tools for bidirectional control of the CaN-Drp1 signaling axis in hand, we demonstrate that the Drp1 L X VP motif shapes mitochondria in neuronal and non-neuronal cells, and that CaN-mediated Drp1 dephosphorylation promotes neuronal death following oxygen-glucose deprivation. These results point to the CaN-Drp1 complex as a potential target for neuroprotective therapy of ischemic stroke.
Dynamin-related Protein 1 Mitochondria Signal Transduction Ischemia Membrane Fusion Calcineurin Mitochondrial Fission Serine-Threonine Protein Phosphatase GTPase Protein-Protein Interactions

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