Molecular chaperones are typically referred to as proteins that associate with and help other proteins reach a native conformation while not being present in the end state. Chaperones bind to their substrate (i.e. a misfolded protein) in an ATP-dependent manner to perform a specific function. Exposed hydrophobic residues are a major problem with regards to protein aggregation because they can interact with one another and form hydrophobic interactions. It is the job of chaperones to prevent this aggregation by binding to the residues or providing proteins a “safe” environment to fold properly. Heat shock proteins are also believed to play a role in the presentation of pieces of proteins (or peptides) on the cell surface to help the immune system recognize diseased cells. The major HSPs involved in the HSR include HSP70, HSP90, and HSP60. Chaperones include the HSP70s and HSP90s while HSP60s are considered to be chaperonins.