title: A calcineurin docking motif (LXVP) in dynamin-related protein 1 contributes to mitochondrial fragmentation and ischemic neuronal injury.
abstract: 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 LXVP motif, which mediates the interaction between the phosphatase and mechanoenzyme. We mutated the LXVP motif in Drp1 to either increase or decrease similarity to the prototypical LXVP 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 LXVP 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 LXVP 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.
authors.affiliation: Department of Pharmacology, University of Iowa, Iowa City, Iowa 52242, USA.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Slupe
authors.forename: Ronald A
authors.initials: RA
authors.lastname: Merrill
authors.forename: Kyle H
authors.initials: KH
authors.lastname: Flippo
authors.forename: Mark A
authors.initials: MA
authors.lastname: Lobas
authors.forename: Jon C D
authors.initials: JC
authors.lastname: Houtman
authors.forename: Stefan
authors.initials: S
authors.lastname: Strack
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D002545:Brain Ischemia / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D019703:Calcineurin / Q000235:genetics / Q000378:metabolism; D016923:Cell Death; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism; D034281:Dynamins / Q000235:genetics / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism; D050778:NFATC Transcription Factors / Q000235:genetics / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism* / Q000473:pathology; D010766:Phosphorylation / Q000235:genetics; D054648:Protein Phosphatase 2 / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020521:Stroke / Q000235:genetics / Q000378:metabolism* / Q000473:pathology
chemical_list: D024101:Mitochondrial Proteins; D050778:NFATC Transcription Factors; D009419:Nerve Tissue Proteins; D017868:Cyclic AMP-Dependent Protein Kinases; D019703:Calcineurin; C514014:Ppp2ca protein, rat; D054648:Protein Phosphatase 2; C519851:Dnm1l protein, rat; D034281:Dynamins