K. Yoshida et al., TRANSLOCATION OF PROTEIN-KINASE C-ALPHA, C-DELTA AND C-EPSILON ISOFORMS IN ISCHEMIC RAT-HEART, Biochimica et biophysica acta. Molecular basis of disease, 1317(1), 1996, pp. 36-44
To explore the spatial and temporal localization of PKC isoforms durin
g ischemia, we quantified PKC isoforms in the subcellular fractions in
perfused rat heart by immunoblotting using specific antibodies agains
t PKC isoforms. PKCs-alpha and epsilon translocated from the 100 000 X
g supernatant (S, cytosolic) fraction to the 1000 x g pellet (P1, nuc
leus-myofibril) and the 1000-100 000 X g pellet (P2, membrane) fractio
ns during 5-40 min of ischemia. PKC-delta redistributed from the P2 to
the S fraction. A 50-kDa fragment of PKC-cu appeared during ischemia
possibly through calpain action. Immunohistochemical observations show
ed the different localizations of PKC-alpha, delta, and epsilon in the
myocytes. The PKC assay displayed high basal levels of Ca2+-independe
nt PKC, the activation of Ca2+-dependent PKC in the P1 and P2 fraction
s, and the activation of Ca2+-independent PKC in the P1 fraction after
20 min of ischemia.