The mouse Hsp60 is a member of a highly conserved family which includes molecular chaperones from several species such as plant Hsp60 (known as Rubisco binding protein), GroEL, the E.coli Hsp60 and 65kD major antigen of mycobacteria. In eukaryotes, Hsp60 is localized in the mitochondrial matrix and in plants Hsp60 is localized in the chloroplast. Mitochondria, chloroplasts and bacteria have a common ancestry (> 1billion years) and this fact together with the high degree of homology between the divergent Hsp60s would indicate that these proteins carry out a primitive but important function which is similar to all of these different species. The common characteristics of the Hsp60s from the divergent species are i) high abundance, ii) induction with environmental stress such as heat shock, iii) homo-oligomeric structures of either 7 or 14 subunits which reversibly dissociate in the presence of Mg2+ and ATP, iv) ATPase activity and v) a role in folding and assembly of oligomeric protein structures (1). These similarities are supported by recent studies where the single-ring human mitochondrial homolog, Hsp60 with its co-chaperonin, Hsp10 were expressed in a E. coli strain, engineered so that the groE operon is under strict regulatory control. This study has demonstrated that expression of Hsp60-Hsp10 was able to carry out all essential in vivo functions of GroEL and its co-chaperonin, GroES (2). Consistent with their functions as chaperones, Hsp60 and Hsp10 have been suggested to act as docking molecules with a passive role in the maturation of caspase processing. Data demonstrates that recombinant Hsp60 and Hsp10 have been shown to accelerate the activation of procaspase-3 by cytochrome c and dATP in an ATP-dependent manner (3). Hsps are intracellular proteins which are thought to serve protective functions against infection and cellular stress, however several recent studies indicate that members of the Hsp60 family are linked to a number of autoimmune diseases, artherosclerosis and chlamydial disease. Although overexpression of self Hsp60 in the synovial tissue of rheumatoid arthritic (RA) patients and cellular as well as humoral reactivities against Hsp60 molecules in RA have been demonstrated, a role for these activities remains to be elucidated (4). Applications: Suitable for use in Western Blot analysis. We recommend that the material be diluted in SDS containing sample buffer (e.g. Laemmli, U.K., (1970) Nature 277: 680-685) and heated at 100C for 5 minutes prior to use. On a 15-well minigel system, 50ng of protein per lane should be sufficient when used in a colorimetric Western Blot. This protein does not contain GroEL as determined by Western Blot analysis. Storage and Stability: May be stored at 4C for short-term only. For long-term storage, aliquot to avoid repeated freezing and thawing and freeze at -70C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Aliquots are stable for at least 12 months.
