InterPro domain: IPR036533
General Information
- Identifier IPR036533
- Description BAG domain superfamily
- Number of genes 1064
- Gene duplication stats Loading...
- Associated GO terms GO:0051087
Abstract
BAG domains are present in Bcl-2-associated athanogene 1 and silencer of death domains. The BAG proteins are modulators of chaperone activity, they bind to HSP70/HSC70 proteins and promote substrate release. The proteins have anti-apoptotic activity and increase the anti-cell death function of BCL-2 induced by various stimuli. BAG-1 binds to the serine/threonine kinase Raf-1 or Hsc70/Hsp70 in a mutually exclusive interaction. BAG-1 promotes cell growth by binding to and stimulating Raf-1 activity. The binding of Hsp70 to BAG-1 diminishes Raf-1 signalling and inhibits subsequent events, such as DNA synthesis, as well as arrests the cell cycle. BAG-1 has been suggested to function as a molecular switch that encourages cells to proliferate in normal conditions but become quiescent under a stressful environment [ 1 , 2 ].
BAG-family proteins contain a single BAG domain, except for human BAG-5 which has four BAG repeats [ 3 ]. The BAG domain is a conserved region located at the C terminus of the BAG-family proteins that binds the ATPase domain of Hsc70/Hsp70. The BAG domain is evolutionarily conserved, and BAG domain containing proteins have been described and/or proven in a variety of organisms including Mus musculus (Mouse), Xenopus spp., Drosophila spp., Bombyx mori (Silk moth), Caenorhabditis elegans, Saccharomyces cerevisiae (Baker's yeast), Schizosaccharomyces pombe (Fission yeast), and Arabidopsis thaliana (Mouse-ear cress).
The BAG domain has 110-124 amino acids and is comprised of three anti-parallel alpha-helices, each approximately 30-40 amino acids in length. The first and second helices interact with the serine/threonine kinase Raf-1 and the second and third helices are the sites of the BAG domain interaction with the ATPase domain of Hsc70/Hsp70. Binding of the BAG domain to the ATPase domain is mediated by both electrostatic and hydrophobic interactions in BAG-1 and is energy requiring.
1. What's in the 'BAG'?--A functional domain analysis of the BAG-family proteins. Cancer Lett. 188, 25-32
2. BAG4/SODD protein contains a short BAG domain. J. Biol. Chem. 277, 31172-8
3. The C-terminal BAG domain of BAG5 induces conformational changes of the Hsp70 nucleotide-binding domain for ADP-ATP exchange. Structure 18, 309-19