Association of HSPB2, a member of the small heat shock protein family, with mitochondria

Citation
M. Nakagawa et al., Association of HSPB2, a member of the small heat shock protein family, with mitochondria, EXP CELL RE, 271(1), 2001, pp. 161-168
Citations number
44
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Cell & Developmental Biology
Journal title
EXPERIMENTAL CELL RESEARCH
ISSN journal
0014-4827 → ACNP
Volume
271
Issue
1
Year of publication
2001
Pages
161 - 168
Database
ISI
SICI code
0014-4827(20011115)271:1<161:AOHAMO>2.0.ZU;2-I
Abstract
We previously identified HSPB2, a new member of the small heat shock protei n family, expressed in heart and skeletal muscles. In this study, we used a polyclonal anti-HSPB2 antibody and examined the subcellular localization o f HSPB2 in differentiated C2C12 cells, KNS-81 cells, and NIH3T3 transfectan ts expressing human HSPB2. Double staining with anti-HSPB2 and various mark ers for cytoplasmic structures showed that HSPB2 was present in the cytosol as granules, some of which colocalized with mitochondria. This colocalizat ion was not altered by a colchicine treatment, indicating that it is indepe ndent of microtubules. The subcellular fractionation of differentiated C2C1 2 cells revealed that HSPB2 was mainly detected in the postmitochondrial su pernatant, but mild heat treatment enriched the amount of HSPB2 in the mito chondrial fraction. The expression of HSPB2 protected the cells from heat-i nduced cell death. In addition, Northern blot analysis revealed that expres sion of HSPB2 mRNA is higher in slow-twitch muscle than in fast-twitch musc le, which correlates with the amounts of mitochondria present in these two types of tissue. Taken together, these results suggest that HSPB2 may not l ocalize in the matrix, but rather associates with the outer membrane compon ents of the mitochondria and thus plays a role in the stress response. (C) 2001 Academic Press.