Hsp25/Hsp27 Monoclonal Antibody (Clone 8A7)

Applications

ICC, IP, WB

Form

25 microg

Weight

0

Storage Temp

-20

Additional Info

Heat shock protein 25 (Hsp25) is the mouse homologue of the human Hsp27 protein, a member of the small Hsp family comprised of a diverse group of proteins from ~15 to >30 kDa. The basic structure of most Hsps is a homologous and highly conserved amino acid sequence, with an .alpha.-crystallin-domain at the C-terminus and the WD/EPF domain at the less conserved N-terminus. This N-terminus is essential for the development of high molecular weight oligomers. Hsp27-oligomers consist of stable dimers formed by as many as 8-40 Hsp27 protein monomers. The oligomerization status is connected with the chaperone activity, whereas dimers have no chaperone activity. Hsp27 is localized to the cytoplasm of unstressed cells but can redistribute to the nucleus in response to stress where it may function to stabilize DNA and/or the nuclear membrane. It can be rapidly phosphorylated in response to physiological stimuli relevant to the cell type examined. Thus, Hsp27 has been suggested to be an important intermediate in second messenger-mediated signaling pathways. Other functions include chaperone activity (as mentioned above), thermo-tolerance in vivo, inhibition of apoptosis, and signal transduction. Specifically, in vitro, Hsp27 acts as an ATP-independent chaperone by inhibiting protein aggregation and by stabilizing partially denatured proteins, which ensures refolding of the Hsp70 complex. Hsp27 is also involved in the apoptotic signaling pathway because it interferes with the activation of cytochrome C/Apaf-1/dATP complex, thereby inhibiting the activation of procaspase-9. It is also hypothesized that Hsp27 may serve some role in cross-bridge formation between actin and myosin. Hsp27 is also thought to be involved in the process of cell differentiation. The up-regulation of Hsp27 correlates with the rate of phosphorylation and with an increase of large oligomers. It is possible that Hsp27 may play a crucial role in termination of growth.