True statement about chaperones:

A, B, C i.e. Belong to heat shock proteins; Wide range of expression; Present from bacteria to human - Chaperones (heat shock or stress proteins) are present in wide range of species from bacteria to humansQ Chaperones are proteins that play a role in the assembly or proper folding of other proteins without themselves being component of the later. They prevent faulty folding and unproductive interactions of other proteins by stabilizing paially folded or unfolded intermediates, allowing them time to fold properly. Chaperones are folding proteins which prevent faulty folding and unproductive interactions. These include chaperonins like mt Gro EL (from complex barrel like structures in which unfolded protein is retained for proper folding); BiP (immunoglobulin heavy chain binding protein), GRP-94 (glucose related protein), calnexin and calreticulinQ and enzymes such as PDI (protein disulfide isomerase) & PPI (petidyl prolyl cis-trans-isomerase). All these are located in rough endoplasmic reticulum (RER).