title: Ischemia-induced association of the stress protein alpha B-crystallin with I-band portion of cardiac titin.
abstract: During ischemia the cardiac stress protein, alpha B-crystallin, was shown by immunoelectron microscopy to translocate to the N(2)-line area of myofibrillar I-bands of rat cardiomyocytes where alpha B-crystallin resisted extraction with 1 m NaSCN and 2 m urea as did titin. Actin became completely extracted under these conditions, indicating association of alpha B-crystallin with titin the only remaining non-actin cytoskeletal component of I-bands outside Z-disks. Titin, extracted from ischemic pig myocardium, was shown to copurify with alpha B-crystallin. Further evidence for binding of alpha B-crystallin to titin was obtained by dot-blot assays in which biotinylated alpha B-crystallin was demonstrated to bind to the titin-enriched fraction immobilized on nitrocellulose. Binding of alpha B-crystallin to titin during cardiac ischemia could serve to stabilize titin against denaturation and might provide an endogenous mechanism to delay ischemic damage of this important elastic component of myofibrils.
authors.affiliation: Institute of Anatomy and Cell Biology, Julius-Maximilians-University, Koellikerstr. 6, D-97070 Würzburg, Germany. nikola.golenhofen@mail.uni-wuerzburg.de
authors.forename: Nikola
authors.initials: N
authors.lastname: Golenhofen
authors.forename: Anja
authors.initials: A
authors.lastname: Arbeiter
authors.forename: Rainer
authors.initials: R
authors.lastname: Koob
authors.forename: Detlev
authors.initials: D
authors.lastname: Drenckhahn
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D015153:Blotting, Western; D064211:Connectin; D003459:Crystallins / Q000378:metabolism*; D008297:Male; D016253:Microscopy, Immunoelectron; D009124:Muscle Proteins / Q000302:isolation & purification / Q000378:metabolism*; D017202:Myocardial Ischemia / Q000378:metabolism*; D009206:Myocardium / Q000473:pathology* / Q000648:ultrastructure; D011485:Protein Binding; D011494:Protein Kinases / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013552:Swine
chemical_list: D000199:Actins; D064211:Connectin; D003459:Crystallins; D009124:Muscle Proteins; C577295:Ttn protein, rat; D011494:Protein Kinases