Hsp70 Activator, YM-1

A cell-permeable rhodacyanine derivative that stabilizes Hsp70 (heat-shock protein 70) in its ADP-bound, substrate-binding conformation via reversible binding to Hsp70 nucleotide-binding domain (K_D = 4.9 µM using YM-1-biotin) in a manner similar to the physiological Hsp70 co-chaperone Hip and YM-1 is shown to compete against Hip for Hsp70 binding. Both Hip overexpression and YM-1 treatment are shown to enhance cellular nNOS ubiquitination (2.57-fold of DMSO control monoUb nNOS level; 1 µM for 24 h) in nNOS-expressing HEK293 cells and promote proteasomal clearance of AR (androgen receptor) ligand-induced accumulation of unfolded AR112Q aggregates (by 35% with 1 µM YM-1 treatment for 72 h post 4 h 10 nM R1881 induction) in polyQ AR-expressing PC12 cultures. Likewise, YM-1, when co-supplemented with AR ligand dihydrotestosterone in food (1 mM each), reduces DHT-induced toxicity in transgenic Drosophila expressing human polyQ AR AR52Q as assessed by the severeness of rough eye phenotype and pupal eclosion rate. Also reported to downregulate Akt1/2 level in MCF7 cancer cells in a dose-dependent manner (by 53% with 6 h 10 µM treatment) and sensitize 4-OHT resistant TR-MCF7 to proliferation inhibition by 4-OHT in MTT assays (by 55%; 4 h 10 µM YM-1 alone prior to 44 h 10 µM 4-OHT treatment alone).

A stable and soluble MKT-077 analog that acts an allosteric activator of heat-shock protein 70 (HSP70). Its action appears to be similar to HSP70 interacting protein (HIP). Shown to convert HSP70 to its tight-affinity conformation and promote the accumulation of the ADP-bound form of HSP70. Increases the binding of HSP70 to its unfolded substrates . Also shown to enhance ubiquitination and degradation of nNOS and polyglutamine androgen receptor (polyQ AR) (at ~1 mM). Displays selective cytotoxicity across multiple cancer cell lines without affecting the normal cells. Also reported to restore tamoxifen sensitivity to a refractory tamoxifen-resistant MCF7 cells (~10 mM).

Please note that the molecular weight for this compound is batch-specific due to variable water content. Please refer to the vial label or the certificate of analysis for the batch-specific molecular weight. The molecular weight provided represents the baseline molecular weight without water.

Cell permeable: yes

Primary Target
HSP70

Reversible: yes

Packaged under inert gas

Following reconstitution, aliquot and freeze (-20°C). Stock solutions are stable for up to 3 months at -20°C.

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Koren, J. 3rd, et al. 2012. PLoS. One.7, e35566.
Rousaki, A., et al. 2011. J. Mol. Biol.411, 614.

CALBIOCHEM is a registered trademark of Merck KGaA, Darmstadt, Germany

Toxicity: Standard Handling (A)