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PKD Translocation to the Outer Mitochondrial Membrane Induces Mitochondrial Fragmentation and Cell Death via DLP1 Phosphorylation in Cardiomyocytes
Author(s) -
Jhun Bong Sook,
OUchi Jin,
Mishra Jyotsna,
Xu Xiaole,
Hurst Stephen,
Mende Ulrike,
Sheu SheyShing
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.742.7
Subject(s) - microbiology and biotechnology , mitochondrion , phosphorylation , biology , mitochondrial permeability transition pore , mitochondrial fusion , chemistry , apoptosis , programmed cell death , mitochondrial dna , biochemistry , gene
Heart failure (HF) occurs in response to various types of stimulus including G q ‐protein coupled receptor (G q PCR) stimulation. G q PCR‐mediated mitochondrial dysfunction is frequently observed in HF animal models, but the molecular mechanism remains unclear. Recently, Protein kinase D (PKD) located at G q PCR downstream has been recognized as a key signaling nodal point affecting various cardiac functions. Therefore, we hypothesize that PKD acts as a mitochondrial signaling component and induces mitochondrial dysfunctions under G q PCR‐mediated HF. Using the outer mitochondrial membrane (OMM)‐targeted CFP (mt‐CFP), we found that the value of the Förster resonance energy transfer (FRET) between mt‐CFP and YFP‐tagged PKD significantly increases upon G q PCR stimulation, indicating PKD translocation from cytosol to the OMM. Next, using the FRET‐based OMM‐targeted PKD‐activity sensor, we observed that PKD is activated at the OMM after G q PCR stimulation. Furthermore, we found that G q PCR‐mediated PKD activation at the OMM induced mitochondrial fragmentation, increased reactive oxygen species generation and mitochondrial permeability transition pore opening, followed by caspase‐3 activation in cardiomyocytes. These morphological and functional alterations in cardiac mitochondria were mediated via PKD‐dependent phosphorylation of Dynamin‐Like Protein 1 (DLP1) at S637. Importantly, PKD‐dependent DLP1 phosphorylation concurrent with abnormal mitochondrial morphology and apoptotic signaling were also observed in ventricular tissue from transgenic mice with cardiac‐specific overexpression of constitutively active Ga q . In summary, we conclude that G q PCR stimulation induces PKD translocation to the OMM and induces mitochondrial fragmentation and dysfunction, which likely contributes to cardiomyocyte dysfunction during HF. Support or Funding Information This work was partly supported by American Heart Association (AHA) grant (14BGIA18830032 to J.O.‐U.), Medical Research Grant from W.W. Smith Charitable Trust (H1403 to J.O.‐U.) and NIH grants (2R01HL093671 and 1R01HL122124 to SSS).