Small Heat Shock Protein αB-Crystallin Is Part of Cell Cycle-dependent Golgi Reorganization*
- ‡Jules Stein Eye Institute, §Brain Research Institute, ¶Geffen School of Medicine and Molecular Biology Institute, University of California, Los Angeles, California 90095-7000
- ↵∥ A Research to Prevent Blindness Inc., Wasserman Merit Scholar. To whom correspondence should be addressed: Vision Molecular Biology Laboratory, Jules Stein Eye Inst., BH 623, Geffen School of Medicine at UCLA, Los Angeles, CA 90095-7000. Tel.: 310-825-9543; Fax: 310-794-2144; E-mail: bhat{at}jsei.ucla.edu.
Abstract
αB-Crystallin is a developmentally regulated small heat shock protein known for its binding to a variety of denatured polypeptides and suppression of protein aggregation in vitro. Elevated levels of αB-crystallin are known to be associated with a number of neurodegenerative pathologies such as Alzheimer disease and multiple sclerosis. Mutations in αB-crystallin gene have been linked to desminrelated cardiomyopathy and cataractogenesis. The physiological function of this protein, however, is unknown. Using discontinuous sucrose density gradient fractionation of post-nuclear supernatants, prepared from rat tissues and human glioblastoma cell line U373MG, we have identified discrete membrane-bound fractions of αB-crystallin, which co-sediment with the Golgi matrix protein, GM130. Confocal microscopy reveals co-localization of αB-crystallin with BODIPY TR ceramide and the Golgi matrix protein, GM130, in the perinuclear Golgi in human glioblastoma U373MG cells. Examination of synchronized cultures indicated that αB-crystallin follows disassembly of the Golgi at prometaphase and its reassembly at the completion of cytokinesis, suggesting that this small heat shock protein, with its chaperone-like activity, may have an important role in the Golgi reorganization during cell division.
- Received August 5, 2004.
- Revision received August 20, 2004.
- The American Society for Biochemistry and Molecular Biology, Inc.
