The heat shock protein, Hsp70 is part of the Hsp70 family which contains a number of highly-related protein isoforms ranging in size from 66kD to 78kD. The 70kD heat shock cognate protein, Hsc70 is closely related biochemically and biologically to Hsp70 and is part of the Hsp70 family. These proteins include both cognate members which are found within major intracellular compartments and highly inducible isoforms which appear to be predominantly cytoplasmic or nuclear in distribution (1). Members of the Hsp70 family are molecular chaperones which are involved in many cellular functions such as protein folding, transport, maturation and degradation and they exert their function in an ATPdependent manner. The molecular chaperones of the Hsp70 family recognize and bind to nascent polypeptide chains as well as partially folded intermediates of proteins preventing their aggregation and misfolding and the binding of ATP triggers a critical conformational change leading to the release of the bound substrate protein (2). Recent data has demonstrated that BAG-1 which possesses a ubiquitin-like domain at its amino terminus and which has been shown to associate with the 26S proteosome in HeLa cells, modulates the chaperone activity of Hsc70 and Hsp70. These findings reveal a role of BAG-1 as a physical link between the Hsc70/Hsp70 chaperone system and the proteasome (3). There is also experimental data which shows that the ATPase domain and the substrate binding domain of Hsp70 (or Hsc70) cooperate and form a cochaperone-chaperone complex with the synaptic vesicle cysteine string protein (csp) which is essential for normal neurotransmitter release (4). Applications: Suitable for use in Western Blot analysis. If this protein is to be used for Western blot analysis, we recommend that the material be diluted into an appropriate amount of SDS-PAGE sample buffer. On a 15-well minigel system, 100ng of protein per lane should be sufficient when used in a colorimetric Western Blot and an appropriate alkaline phosphatase conjugated secondary antibody for detection. This protein does not contain DnaK or Hsc70 as demonstrated by Western Blot analysis. Functional Assay: This protein has tested positive for ATPase activity. Storage and Stability: Aliquot to avoid repeated freezing and thawing and store at -70C. Aliquots are stable for 6 months after receipt. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.
