TY - JOUR
T1 - Molecular mechanism underlying adenosine receptor-mediated mitochondrial targeting of protein kinase C
AU - Yang, Zhaogang
AU - Sun, Wei
AU - Hu, Keli
N1 - Funding Information:
We would like to thank Lane Wallace for critical reading of the manuscript and Jack Yalowich for helpful discussions in the revised manuscript. This work was supported in part by a research grant from the American Heart Association National Center and funds from The Ohio State University .
PY - 2012/4
Y1 - 2012/4
N2 - Activation of protein kinase C (PKC) via adenosine receptors is known to be involved in the cardioprotection of ischemic preconditioning (IPC). Specifically, activation of PKCε is critical for cardioprotection. There is ample evidence that PKCε resides in cardiac mitochondria. However, the signals that promote translocation of PKCε are largely unknown. The present study was designed to determine whether and how adenosine receptor activation induces translocation of PKCε to mitochondria. Freshly isolated adult rat cardiac myocytes and rat heart-derived H9c2 were used in the study. Immunofluorescence imaging of isolated mitochondria showed that PKCε but not PKCδ was localized in mitochondria and this mitochondrial localization of PKCε was significantly increased by adenosine treatment. The adenosine-induced increase in PKCε-positive mitochondria was largely prevented not only by PKC inhibitor chelerythrine, but also by the HSP90 inhibitor geldanamycin and by siRNA targeting HSP90. Immunoblot analysis from percoll-purified mitochondria further demonstrated that adenosine mediated a significant increase in mitochondrial PKCε[U+F020] but not PKCδ. This effect was blocked by inhibiting PKC activity with chelerythrine and bisindolylmaleimide. Furthermore, co-immunoprecipitation data showed that PKCε but not PKCδ was associated with TOM70 and HSP90, and this association was enhanced by adenosine treatment. Moreover, adenosine-induced association of PKCε with TOM70 was reduced by suppressing HSP90 expression with siRNA. In conclusion, we demonstrate that adenosine induces HSP90-dependent translocation of PKCε to mitochondria, possibly through mitochondrial import machinery TOM70. These results point out a novel mechanism in regulating PKC in mitochondria and suggest an important implication in ischemic preconditioning or postconditioning.
AB - Activation of protein kinase C (PKC) via adenosine receptors is known to be involved in the cardioprotection of ischemic preconditioning (IPC). Specifically, activation of PKCε is critical for cardioprotection. There is ample evidence that PKCε resides in cardiac mitochondria. However, the signals that promote translocation of PKCε are largely unknown. The present study was designed to determine whether and how adenosine receptor activation induces translocation of PKCε to mitochondria. Freshly isolated adult rat cardiac myocytes and rat heart-derived H9c2 were used in the study. Immunofluorescence imaging of isolated mitochondria showed that PKCε but not PKCδ was localized in mitochondria and this mitochondrial localization of PKCε was significantly increased by adenosine treatment. The adenosine-induced increase in PKCε-positive mitochondria was largely prevented not only by PKC inhibitor chelerythrine, but also by the HSP90 inhibitor geldanamycin and by siRNA targeting HSP90. Immunoblot analysis from percoll-purified mitochondria further demonstrated that adenosine mediated a significant increase in mitochondrial PKCε[U+F020] but not PKCδ. This effect was blocked by inhibiting PKC activity with chelerythrine and bisindolylmaleimide. Furthermore, co-immunoprecipitation data showed that PKCε but not PKCδ was associated with TOM70 and HSP90, and this association was enhanced by adenosine treatment. Moreover, adenosine-induced association of PKCε with TOM70 was reduced by suppressing HSP90 expression with siRNA. In conclusion, we demonstrate that adenosine induces HSP90-dependent translocation of PKCε to mitochondria, possibly through mitochondrial import machinery TOM70. These results point out a novel mechanism in regulating PKC in mitochondria and suggest an important implication in ischemic preconditioning or postconditioning.
KW - Adenosine
KW - Cardiac myocyte
KW - Heat shock protein
KW - Mitochondria
KW - Mitochondrial import
KW - Protein kinase c
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U2 - 10.1016/j.bbamcr.2011.12.012
DO - 10.1016/j.bbamcr.2011.12.012
M3 - Article
C2 - 22233927
AN - SCOPUS:84862820687
SN - 0167-4889
VL - 1823
SP - 950
EP - 958
JO - Biochimica et Biophysica Acta - Molecular Cell Research
JF - Biochimica et Biophysica Acta - Molecular Cell Research
IS - 4
ER -