An RNA Aptamer Specific to Hsp70-ATP Conformation Inhibits its ATPase Activity Independent of Hsp40

Thirunavukarasu, Deepak; Shi, Hua

doi:10.1089/nat.2014.0510

Cited by 14 publications

(15 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, the aptamer binding may also sterically block substrate binding to Hsp70. Previously, we demonstrated that the aptamer inhibited Hsp70 ATPase activity in the presence of Hsp40, but did not affect the stimulatory effect of Hsp40 on this ATPase activity [26], therefore the reduction of folding efficiency observed here is unlikely due to a destabilization of interaction between Hsp70 and Hsp40 by the aptamer. The destabilization of Hsp70-subsrate interaction may further affect Hsp70 capability to assist in substrate folding.…”

Section: Resultssupporting

confidence: 41%

“…1A), which indicated that the aptamer destabilized Hsp70-substrate interaction. Since the aptamer inhibits Hsp70 ATPase activity [26], it may be destabilizing Hsp70-substrate interaction by impeding the transition to Hsp70-ADP state that has a higher affinity for substrates [14,15,31,32]. In addition, the aptamer binding may also sterically block substrate binding to Hsp70.…”

Section: Resultsmentioning

confidence: 99%

“…Electrophoretic mobility shift assay (EMSA) was performed as described previously [26]. Briefly, 30 nM of 32 Plabeled RNA aptamer was incubated with protein in 15 mL binding reactions.…”

Section: Electrophoretic Mobility Shift Assaymentioning

confidence: 99%

“…Given the importance of the ATPase cycle in Hsp70 function, reagents that bind Hsp70-ATP and modulate its ATPase activity directly would be useful in dissecting the protein triage mechanism. For this purpose, we recently generated an Hsp70-ATP conformation-specific RNA aptamer, AptHsp70-1 [26]. Interestingly, the aptamer inhibited both intrinsic and Hsp40-stimulated ATPase activities of Hsp70 [26].…”

mentioning

confidence: 99%

“…For this purpose, we recently generated an Hsp70-ATP conformation-specific RNA aptamer, AptHsp70-1 [26]. Interestingly, the aptamer inhibited both intrinsic and Hsp40-stimulated ATPase activities of Hsp70 [26]. In this study, we utilize this aptamer as a tool in reconstituted in vitro folding and degradation assays to gain insights into the mechanism of this triage process and to explore new therapeutic possibilities.…”

mentioning

confidence: 99%

See 4 more Smart Citations

Aptamer-Enabled Manipulation of the Hsp70 Chaperone System Suggests a Novel Strategy for Targeted Ubiquitination

Thirunavukarasu

Shi

2016

Nucleic Acid Therapeutics

Self Cite

View full text Add to dashboard Cite

The Hsp70 chaperone system plays an important role in protein quality control by assisting in the folding and clearance of misfolded proteins. However, the mechanism by which it chooses between folding and degradation pathways is not fully understood. In this study, we used an RNA aptamer for Hsp70 to perturb the function of Hsp70 in cell-free systems. We found that the aptamer inhibited both Hsp70-mediated folding and Hsp70-CHIP-mediated ubiquitination/degradation of a misfolded protein substrate. Based on these results, we explored a novel strategy for targeted protein ubiquitination, using an engineered bifunctional aptamer to tether a protein substrate to Hsp70. We demonstrated that increased Hsp70-CHIP-mediated ubiquitination of the tethered protein substrate can be specifically induced by this bifunctional aptamer. This strategy may be useful in selective degradation of disease-causing proteins for therapeutic purposes. In addition, these studies provide insight into the mechanism of Hsp70-mediated protein triage.

show abstract

Section: Resultssupporting

confidence: 41%

Section: Resultsmentioning

confidence: 99%

“…Electrophoretic mobility shift assay (EMSA) was performed as described previously [26]. Briefly, 30 nM of 32 Plabeled RNA aptamer was incubated with protein in 15 mL binding reactions.…”

Section: Electrophoretic Mobility Shift Assaymentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Aptamer-Enabled Manipulation of the Hsp70 Chaperone System Suggests a Novel Strategy for Targeted Ubiquitination

Thirunavukarasu

Shi

2016

Nucleic Acid Therapeutics

Self Cite

View full text Add to dashboard Cite

show abstract

Hsp70 in cancer: A double agent in the battle between survival and death

Vostakolaei

Hatami-Baroogh

Babaei

et al. 2020

Journal Cellular Physiology

View full text Add to dashboard Cite

The heat shock protein (Hsps) superfamily, also known as molecular chaperones, are highly conserved and present in all living organisms and play vital roles in protein fate. The HspA1A (Hsp70‐1), called Hsp70 in this review, is expressed at low or undetectable levels in most unstressed normal cells, but numerous studies have shown that diverse types of tumor cells express Hsp70 at the plasma membrane that leads to resistance to programmed cell death and tumor progression. Hsp70 is released into the extracellular milieu in three forms including free soluble, complexed with cancer antigenic peptides, and exosome forms. Therefore, it seems to be a promising therapeutic target in human malignancies. However, a great number of studies have indicated that both intracellular and extracellular Hsp70 have a dual function. A line of evidence presented that intracellular Hsp70 has a cytoprotective function via suppression of apoptosis and lysosomal cell death (LCD) as well as that extracellular Hsp70 can promote tumorigenesis and angiogenesis. Other evidence showed intracellular Hsp70 can promote apoptosis and membrane‐associated/extracellular Hsp70 can elicit antitumor innate and adaptive immune responses. Given the contradictory functions, as a "double agent," could Hsp70 be a promising tool in the future of targeted cancer therapies? To answer this question, in this review, we will discuss the functions of Hsp70 in cancers besides inhibition and stimulation strategies for targeting Hsp70 along with their challenges.

show abstract

Hsp70: A Cancer Target Inside and Outside the Cell

Boudesco

Cause

Jégo

2017

Methods in Molecular Biology

View full text Add to dashboard Cite

Heat shock protein 70 (Hsp70) is the most ubiquitous stress-inducible chaperone. It accumulates in the cells in response to a wide variety of physiological and environmental insults including anticancer chemotherapy, thus allowing the cell to survive to lethal conditions. Intracellular Hsp70 is viewed as a cytoprotective protein. Indeed, this protein can inhibit key effectors of the apoptotic and autophagy machineries. In cancer cells, the expression of Hsp70 is abnormally high, and Hsp70 may participate in oncogenesis and in resistance to chemotherapy. In rodent models, Hsp70 overexpression increases tumor growth and metastatic potential. Depletion or inhibition of Hsp70 frequently reduces the size of the tumors and can even cause their complete involution. However, HSP70 is also found in the extra-cellular space where it may signal via membrane receptors or endosomes to alter gene transcription and cellular function. Overall, Hsp70 extracellular function is believed to be immnunogenic and the term chaperokine to define the extracellular chaperones such as Hsp70 has been advanced. In this chapter the knowledge to date, as well as some emerging paradigms about the intra- and extra-cellular functions of Hsp70, are presented. The strategies targeting Hsp70 that are being developed in cancer therapy will also be discussed.

show abstract

An RNA Aptamer Specific to Hsp70-ATP Conformation Inhibits its ATPase Activity Independent of Hsp40

Cited by 14 publications

References 64 publications

Aptamer-Enabled Manipulation of the Hsp70 Chaperone System Suggests a Novel Strategy for Targeted Ubiquitination

Aptamer-Enabled Manipulation of the Hsp70 Chaperone System Suggests a Novel Strategy for Targeted Ubiquitination

Hsp70 in cancer: A double agent in the battle between survival and death

Hsp70: A Cancer Target Inside and Outside the Cell

Contact Info

Product

Resources

About