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- Title
Proteolysis of Erythrocyte-Type and Brain-Type Ankyrins in Rat Heart after Postischemic Reperfusion1.
- Authors
Yoshida, Ken-ichi; Harada, Kazuki
- Abstract
Ankyrin links cytoskeleton and integral membrane proteins and is proteolyzed in vitro by calpain, a Ca2+-dependent protease. In the present study, we examined the localization of two ankyrin isoforms, erythrocyte (red blood cell)-type (ankyrinR) and brain-type (an-kyrinB), and their proteolysis after ischemia-reperfusion in the subcellular fractions of perfused rat heart by immunoblotting and by immunohistochemistry using specific antibodies. Both isoforms were observed to be distributed chiefly in the myofibril-nucleus (1,000× g pellet: P1) fraction, while ankyrinR was located substantially in the membrane (100,000× g pellet: P2) fraction. Reperfusion after 10 min or more of global ischemia induced preferential proteolysis of ankyrinR in the P2 fraction and ankyrinB in the PI fraction. The proteolysis of ankyrinR, but not ankyrinB, was effectively inhibited by the synthetic calpain inhibitor acethyl-leucyl-leucyl-norleucinal. The immunohistochemical examination showed that anti-ankyrinR delineated striations, sarcolemma and nuclei, and the staining was decreased after ischemia-reperfusion, while anti-ankyrinB showed diffuse staining. The proteolysis of ankyrinR may interfere with force conduction through disruption of the linkage between integral membrane proteins and the myofibril-cytoskeleton.
- Subjects
ANKYRINS; CYTOSKELETON; CALPAIN; ERYTHROCYTE membranes; PROTEOLYSIS
- Publication
Journal of Biochemistry, 1997, Vol 122, Issue 2, p279
- ISSN
0021-924X
- Publication type
Article
- DOI
10.1093/oxfordjournals.jbchem.a021750