title: Comparative proteomics analysis of differentially expressed phosphoproteins in adult rat ventricular myocytes subjected to diazoxide preconditioning.
abstract: Mitochondrial ATP sensitive potassium channels (mitoK(ATP) channels) are involved in the cardioprotection afforded by ischemic preconditioning (IPC) and diazoxide, a selective mitoK(ATP) channel opener. The activation of some kinases, including phoshoprotein kinase (PKC)-epsilon and mitogen-activating protein kinases (MAPK), is involved in signal conduction of preconditioning downstream from mitoK(ATP) channel opening. Diazoxide can open mitoK(ATP) channels and activate PKC-epsilon, which will phosphorylate some substrate proteins. These proteins that exhibit altered post-translational modification via phosphorylation due to diazoxide pretreatment may be the target molecules and play an important role in cellular protection after mitoK(ATP) channel opening. To analyze and identify the phosphoproteins associated with diazoxide preconditioning, phosphoprotein enrichment and comparative two-dimensional gel electrophoresis (2D-GE) were used. Cultured adult rat ventricular myocytes were pretreated in the presence and absence of 100 micronol/1l diazoxide for 10 min and enriched phosphoproteins from control myocytes and those pretreated with 100 micromol/l diazoxide were separated by 2D-GE and stained with a silver staining kit. Phosphoproteins of interest were further identified by matrix-assisted laser desorption ionization tandem mass spectrometry (MALDI-TOF MS). Eight protein spots with different abundance were found, of which six differentially expressed proteins were identified by MALDI-TOF MS. They included 94 kDa glucose-regulated protein, calpactin I heavy chain, chaperonin containing TCP-1 zeta subunit, hypothetical protein XP_346548, ferritin light chain and ferritin light chain 2. These findings provide new clues to understanding the mechanism of ischemic preconditioning in cardiomyocytes downstream from mitoK(ATP) channel opening.
authors.affiliation: Department of Anesthesiology Xinqiao Hospital Third Military Medical University Chongqing, China. lh78553@hotmail.com
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.forename: Ying-Bin
authors.initials: YB
authors.lastname: Xiao
authors.forename: Yu-Qi
authors.initials: YQ
authors.lastname: Gao
authors.forename: Tian-De
authors.initials: TD
authors.lastname: Yang
mesh_terms: D000818:Animals; D017302:Annexins / Q000032:analysis; D002478:Cells, Cultured; D018833:Chaperonins / Q000032:analysis; D003981:Diazoxide / Q000494:pharmacology*; D015180:Electrophoresis, Gel, Two-Dimensional / Q000379:methods; D005293:Ferritins / Q000032:analysis; D018840:HSP70 Heat-Shock Proteins / Q000032:analysis; D006352:Heart Ventricles; D008297:Male; D008565:Membrane Proteins / Q000032:analysis; D008929:Mitochondria, Heart / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000737:chemistry*; D010455:Peptides / Q000378:metabolism; D010750:Phosphoproteins / Q000032:analysis*; D010766:Phosphorylation; D015221:Potassium Channels / Q000378:metabolism; D040901:Proteomics / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods
chemical_list: D017302:Annexins; D018840:HSP70 Heat-Shock Proteins; D008565:Membrane Proteins; D010455:Peptides; D010750:Phosphoproteins; D015221:Potassium Channels; C018551:glucose-regulated proteins; D005293:Ferritins; D018833:Chaperonins; D003981:Diazoxide