Interaction of the human DnaJ homologue, HSJ1b with the 90 kDa heat shock protein, Hsp90

The 90 kDa heat shock protein (Hsp90) is a major cytoplasmic molecular chap erone associating with numerous other proteins. Both genetic and in vitro r efolding experiments using reticulocyte lysate have suggested a functional interaction of Hsp90 with yeast human homologues of E. coil DnaJ. Here we p resent direct evidence using surface plasmon resonance that Hsp90 and the h uman DnaJ homologue, HSJ1b, bind to each other. We also show that Hsp90 and HSJ1b transfer alpha-lactalbumin to each other in an ATP-dependent manner. The two chaperones have additive effects in preventing rhodanese aggregati on. (C) 2000 Elsevier Science Inc. All rights reserved.