Analogues of the Allosteric Heat Shock Protein 70 (Hsp70) Inhibitor, MKT-077, As Anti-Cancer Agents

Li, Xiaokai; Srinivasan, Sharan R.; Connarn, Jamie; Ahmad, Atta; Young, Zapporah T.; Kabza, Adam M.; Zuiderweg, Erik R. P.; Sun, Duxin; Gestwicki, Jason E.

doi:10.1021/ml400204n

Cited by 136 publications

(166 citation statements)

References 23 publications

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“…J-proteins (such as DnaJA1 and DnaJB4) affect the interaction between the NBD and SBD by locating into the area between them (19, 31); nucleotide exchange factors of the BAG family (BAG 1, 3, and 6) interact with tips of the NBD domain lobes (32, 33); the E3-ubiquitin ligase CHIP interacts with the very C terminus (15). Potent synthetic regulators derived from the rhodamine MKT077 interact with a conserved site close to the nucleotide-binding site in hsc-70 (34,35). Other synthetic compounds occupy yet other sites on this protein or its bacterial homologue (36,37).…”

Section: Discussionmentioning

confidence: 99%

Structural and Biological Interaction of hsc-70 Protein with Phosphatidylserine in Endosomal Microautophagy

Morozova¹,

Clement²,

Kaushik

et al. 2016

Journal of Biological Chemistry

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hsc-70 (HSPA8) is a cytosolic molecular chaperone, which plays a central role in cellular proteostasis, including quality control during protein refolding and regulation of protein degradation. hsc-70 is pivotal to the process of macroautophagy, chaperone-mediated autophagy, and endosomal microautophagy. The latter requires hsc-70 interaction with negatively charged phosphatidylserine (PS) at the endosomal limiting membrane. Herein, by combining plasmon resonance, NMR spectroscopy, and amino acid mutagenesis, we mapped the C terminus of the hsc-70 LID domain as the structural interface interacting with endosomal PS, and we estimated an hsc-70/PS equilibrium dissociation constant of 4.7 ؎ 0.1 m. This interaction is specific and involves a total of 4 -5 lysine residues. Plasmon resonance and NMR results were further experimentally validated by hsc-70 endosomal binding experiments and endosomal microautophagy assays. The discovery of this previously unknown contact surface for hsc-70 in this work elucidates the mechanism of hsc-70 PS/membrane interaction for cytosolic cargo internalization into endosomes.hsc-70 (HSPA8) is a constitutively expressed molecular chaperone. The human hsp-70 chaperone family consists of 11 highly homologous members specific to different cellular compartments and organelles (1). hsc-70 resides in the cellular cytosol and nucleus and plays a central role in cellular proteostasis and protein trafficking.Mammalian hsc-70 consists of the following four structural domains: a 44-kDa nucleotide binding domain (NBD) 3 (residues 1-384) with ATPase activity; a 12-kDa substrate binding domain (SBD) that binds to exposed hydrophobic sequences in client proteins (residues 385-505); a 10-kDa helical LID domain (residues 506 -605); and a 5-kDa dynamically unstructured C-terminal domain (CTD) (residues 606 -646) (2). Binding of ATP in the NBD triggers a global conformational change that releases peptide/protein cargo from the SBD (3). Furthermore, hydrolysis of ATP closes the LID and greatly enhances client-SBD affinity (4). This hydrolysis cycle is important in the chaperone activity of hsc-70 as it allows, with the aid of different co-chaperones, iterative binding to clients resulting in protein (re)folding (5). Furthermore, hsc-70 is involved in recruitment of ubiquitin ligases (6), which leads to cargo polyubiquitination and subsequent hsc-70 trafficking to the proteasome or the endocytic pathway for cargo degradation (7).Altogether, hsc-70's multiple interactions allow this chaperone to play an important role in several cellular activities, including ribosomal quality control, protein refolding, proteasome-linked degradation, macroautophagy, endosomal microautophagy, chaperone-mediated autophagy, endoplasmic reticulum/Golgi and mitochondrial targeting, and vesicle clathrin uncoating (8 -17). These activities place hsc-70 as one of the master controllers of cellular proteostasis.To carry out several of these functions, hsc-70 does not only interact with partner proteins but with membrane lipids as ...

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Section: Discussionmentioning

confidence: 99%

Structural and Biological Interaction of hsc-70 Protein with Phosphatidylserine in Endosomal Microautophagy

Morozova¹,

Clement²,

Kaushik

et al. 2016

Journal of Biological Chemistry

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“…For example, analogs of MKT-077 (including JG-98) stabilize the ADP-bound state of Hsc70 and Hsp70 (33) and have anti-proliferative activity in cell-based and animal models of breast cancer (34,35). Likewise, pifithrin-µ (PES) and its analogs bind to the SBD of Hsp70 and have anti-proliferative activity in multiple cancer cells (36)(37)(38).…”

Section: Introductionmentioning

confidence: 99%

X-linked inhibitor of apoptosis protein (XIAP) is a client of heat shock protein 70 (Hsp70) and a biomarker of its inhibition

Cesa¹,

Shao

Srinivasan³

et al. 2018

Journal of Biological Chemistry

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“…The vital role of these proteins in many aspects of cellular functions has led to the development of small molecule inhibitors targeting chaperones for use as anti-cancer agents (1)(2)(3)(4) and therapeutics for neurodegenerative disorders (5)(6)(7)(8).…”

Section: Introductionmentioning

confidence: 99%

The active Hsc70/tau complex can be exploited to enhance tau turnover without damaging microtubule dynamics

Fontaine¹,

Martin²,

Akoury³

et al. 2015

Human Molecular Genetics

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The pathological accumulation of abnormally hyperphosphorylated and aggregated tau, a neuronal microtubule (MT)-associated protein that functions to maintain MT stability, is implicated in a number of hereditary and sporadic neurodegenerative diseases including frontotemporal dementia and Alzheimer's disease. Targeting tau for the treatment of these diseases is an area of intense interest and toward that end, modulation of cellular molecular chaperones is a potential therapeutic target. In particular, the constitutive Hsp70 isoform, Hsc70, seems highly interconnected with tau, preserving tau protein levels and synergizing with it to assemble MTs. But the relationship between tau and Hsc70, as well as the impact of this interaction in neurons and its therapeutic implications remain unknown. Using a human dominant negative Hsc70 that resembles isoform selective inhibition of this important chaperone, we found for the first time that Hsc70 activity is required to stimulate MT assembly in cells and brain. However, surprisingly, active Hsc70 also requires active tau to regulate MT assembly in vivo, suggesting that tau acts in some ways as a co-chaperone for Hsc70 to coordinate MT assembly. This was despite tau binding to Hsc70 as substrate, as determined biochemically. Moreover, we show that while chronic Hsc70 inhibition damaged MT dynamics, intermittent treatment with a small molecule Hsp70 inhibitor lowered tau in brain tissue without disrupting MT integrity. Thus, in tauopathies, where MT injury would be detrimental to neurons, the unique relationship of tau with the Hsc70 machinery can be exploited to deplete tau levels without damaging MT networks.

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Analogues of the Allosteric Heat Shock Protein 70 (Hsp70) Inhibitor, MKT-077, As Anti-Cancer Agents

Cited by 136 publications

References 23 publications

Structural and Biological Interaction of hsc-70 Protein with Phosphatidylserine in Endosomal Microautophagy

Structural and Biological Interaction of hsc-70 Protein with Phosphatidylserine in Endosomal Microautophagy

X-linked inhibitor of apoptosis protein (XIAP) is a client of heat shock protein 70 (Hsp70) and a biomarker of its inhibition

The active Hsc70/tau complex can be exploited to enhance tau turnover without damaging microtubule dynamics

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