HSP70 Antibody: Biotin

HSP70 is a highly conserved protein that is ubiquitously expressed. It can be found in chloroplasts, eukaryotic cytosol, endoplasmic reticulum, and mitochondria, but also embedded in the cell membrane and in the extracellular space (1,2,3,4). Even though HSP70 is one of the most studied heat shock proteins, the export mechanism and method of membrane insertion are not fully understood. The majority of the proteins in the heat shock family lack a consensus signal for secretion via the ER-Golgi pathway (5). Researchers have found that HSP70 may be released from cells via exosomes or secretory vesicles (6). Although HSP70 is ubiquitously expressed, there is not much information about its presence on cell surface. The finding that HSP70 is localized on the cell surface of cancer cells but not normal cells suggests a conformational change of HSP70 in the lower pH environment characteristic of cancer cells (7). The presence of cell membrane embedded HSP70 has been found to increase the stability of cancer cells, thereby protecting tumors from environmental stress (8, 9). Anti-HSP70 antibody, clone 1H11 (Catalog No. SMC-249) is unique from other commercially available antibodies in that it can bind to the extracellular region of the cell membrane embedded HSP70 protein, allowing researchers to differentiate between membrane bound and intracellular HSP70 across cancer cells types.

Conformation-specific antibody for membrane-bound HSP70. Binds to cell surface HSP70 without permeabilization of cell membrane in tumor cell lines. Does not bind to intracellular HSP70 at low concentrations. Cross-reacts with HSC70. Detects a ~70 kDa band in Western Blot.

A 1:250 dilution of SMC-249 was sufficient for detection of cell surface HSP70 in HCT116 cells using Fluorescence-activated cell sorting, applied in flow cytometry, with FITC as the fluorescent probe.

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