– Heat Shock Protein β-11 (HSPB11) is a stress-responsive protein that is required to deal with proteotoxic stresses. HSPB11 is composed of an IFT complex B composed of IFT88, IFT57, TRAF3IP1, IFT52, IFT27, HSPB11 and IFT20 and is detected in placenta. HSPB11 has beeb shown to form oligomeric complexes and prevent the aggregation of in vitro denaturated aldolase and glyceraldehyde-3-phosphate dehydrogenase in accordance with the chaperone model of HSPB1 and HSPB5. HSPB11 overexpression protected against etoposide-induced cell death that correlated with a decreased release of mitochondrial Cytochrome C into the cytosol. Inhibition of HSP90 function completely abrogated the protective effect of HSPB11. This data suggests that at least in the case of HSPB11, interaction with other chaperone machines besides HSPA1A may contribute to functional specificity and cellular functioning.