Irreversibly sickled cell beta-actin: defective filament formation.
It has been demonstrated that cysteine modification in irreversibly sickled cell beta-actin slows down the remodeling of membrane skeletons [Shartava et al.: J Cell Biol 128:805-812, 1995]. This slow remodeling can be due to alterations in spectrin-actin binding and/or actin-actin interactions in irreversibly sickled cell (ISC) membrane skeletons. In these studies we demonstrate that ISC actin binds spectrin normally. However, ISC beta-actin polymerizes and depolymerizes more slowly than control beta-actin, and forms unusual aggregates when placed under polymerizing conditions. Electron microscopic analysis of actin polymers indicated that ISC actin generates a large amount of aggregates which we conclude are due to the structural modification caused by the disulfide bridge between cysteine284 and cysteine373 in beta-actin.
Shartava
A
A
Department of Structural and Cellular Biology, University of South Alabama College of Medicine, Mobile 36688, USA.
Korn
W
W
Shah
A K
AK
Goodman
S R
SR
D008841:Actin Cytoskeleton / Q000648:ultrastructure*; D000199:Actins / Q000097:blood* / Q000378:metabolism; D000755:Anemia, Sickle Cell / Q000097:blood*; D006801:Humans; D008854:Microscopy, Electron; D011108:Polymers; D011485:Protein Binding; D013049:Spectrin / Q000378:metabolism
D000199:Actins; D011108:Polymers; D013049:Spectrin