A novel subfamily of Hsp70s in the endoplasmic reticulum.

The endoplasmic reticulum contains a number of proteins involved in the processing of secretory polypeptides. These include BiP, which is an Hsp70-family member highly conserved throughout evolution. BiP is known to be intimately involved in several aspects of protein biogenesis, but our understanding of these events has been complicated by the recent description of a novel Hsp70-related protein in yeast, Lhauthorp, whose functions overlap with those of BiP. Current indications are that this protein is distributed widely among eukaryotes and that it represents a distinct subfamily of the Hsp70 class of molecular chaperones.