Translocation of protein kinase C isoforms to subcellular targets in ischemic and anesthetic preconditioning.
BACKGROUND
Translocation of protein kinase C (PKC) to subcellular targets is a pivotal signaling step in ischemic preconditioning (IPC). However, to date, it is unknown whether PKC isoforms translocate in anesthetic preconditioning (APC).


METHODS
The PKC blockers chelerythrine and rottlerin and the adenosine triphosphate-dependent potassium (K(ATP)) channel blockers HMR-1098 and 5-hydroxydecanoate were used to assess the role of PKC and K(ATP) channels in isolated perfused rat hearts subjected to IPC or APC (1.5 minimum alveolar concentration isoflurane) followed by 40 min of ischemia and 30 min of reperfusion. Immunohistochemical techniques were used to visualize PKC translocation after preconditioning. In addition, the phosphorylation status of PKC isoforms was assessed.


RESULTS
Chelerythrine, rottlerin, and 5-hydroxydecanoate blocked IPC and APC with respect to functional recovery, albeit IPC at higher concentrations. HMR-1098 did not affect IPC or APC. PKCdelta and PKCepsilon translocated to nuclei in both IPC and APC, which was inhibited by chelerythrine and rottlerin. PKCdelta translocated to mitochondria but not to the sarcolemma, and PKCepsilon translocated to the sarcolemma and intercalated disks but not to mitochondria. Interestingly, PKCepsilon was accumulated at the intercalated disks in control and preconditioned hearts. Phosphorylation of PKCdelta on serine643 was increased in IPC and APC and blocked by chelerythrine and rottlerin, whereas phosphorylation of PKCdelta on threonine505 was increased only in IPC and not blocked by chelerythrine or rottlerin. PKCepsilon on serine729 did not change its phosphorylation status.


CONCLUSIONS
This study indicates that translocation of PKCdelta plays a pivotal role in IPC and APC and suggests that phosphorylation of PKCdelta on serine643 may be of particular relevance in transferring the APC stimulus to mitochondrial K(ATP) channels.
Uecker
Marina
M
Institute of Pharmacology and Toxicology, University of Zurich, Switzerland.
Da Silva
Rafaela
R
Grampp
Thomas
T
Pasch
Thomas
T
Schaub
Marcus C
MC
Zaugg
Michael
M
D018528:ATP-Binding Cassette Transporters; D000777:Anesthetics / Q000494:pharmacology*; D000818:Animals; D015153:Blotting, Western; D002467:Cell Nucleus / Q000201:enzymology; D003326:Coronary Circulation / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D019157:Ischemic Preconditioning, Myocardial; D007527:Isoenzymes / Q000378:metabolism; D054086:KATP Channels; D008297:Male; D008928:Mitochondria / Q000378:metabolism; D009206:Myocardium / Q000201:enzymology / Q000378:metabolism; D010766:Phosphorylation; D015221:Potassium Channels / Q000378:metabolism; D024661:Potassium Channels, Inwardly Rectifying; D011493:Protein Kinase C / Q000378:metabolism*; D021381:Protein Transport / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D012508:Sarcolemma / Q000201:enzymology; D013347:Subcellular Fractions / Q000378:metabolism*
D018528:ATP-Binding Cassette Transporters; D000777:Anesthetics; D007527:Isoenzymes; D054086:KATP Channels; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; C092520:uK-ATP-1 potassium channel; D011493:Protein Kinase C