scholarly journals Biological Actions of the Hsp90-binding Immunophilins FKBP51 and FKBP52

Biomolecules ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 52 ◽  
Author(s):  
Nadia Zgajnar ◽  
Sonia De Leo ◽  
Cecilia Lotufo ◽  
Alejandra Erlejman ◽  
Graciela Piwien-Pilipuk ◽  
...  
Keyword(s):  
Cancer Progression ◽  
Protein Trafficking ◽  
Steroid Receptors ◽  
Telomerase Activity ◽  
Tetratricopeptide Repeats ◽  
Fk506 Binding Protein ◽  
Client Proteins ◽  
Peptidylprolyl Isomerase ◽  
Tpr Domain ◽  
Biological Actions

Immunophilins are a family of proteins whose signature domain is the peptidylprolyl-isomerase domain. High molecular weight immunophilins are characterized by the additional presence of tetratricopeptide-repeats (TPR) through which they bind to the 90-kDa heat-shock protein (Hsp90), and via this chaperone, immunophilins contribute to the regulation of the biological functions of several client-proteins. Among these Hsp90-binding immunophilins, there are two highly homologous members named FKBP51 and FKBP52 (FK506-binding protein of 51-kDa and 52-kDa, respectively) that were first characterized as components of the Hsp90-based heterocomplex associated to steroid receptors. Afterwards, they emerged as likely contributors to a variety of other hormone-dependent diseases, stress-related pathologies, psychiatric disorders, cancer, and other syndromes characterized by misfolded proteins. The differential biological actions of these immunophilins have been assigned to the structurally similar, but functionally divergent enzymatic domain. Nonetheless, they also require the complementary input of the TPR domain, most likely due to their dependence with the association to Hsp90 as a functional unit. FKBP51 and FKBP52 regulate a variety of biological processes such as steroid receptor action, transcriptional activity, protein conformation, protein trafficking, cell differentiation, apoptosis, cancer progression, telomerase activity, cytoskeleton architecture, etc. In this article we discuss the biology of these events and some mechanistic aspects.

Role of the Hsp90-Immunophilin Heterocomplex in Cancer Biology

2020 ◽  
Vol 16 (1) ◽  
pp. 19-28
Author(s):  
Sonia A. De Leo ◽  
Nadia R. Zgajnar ◽  
Gisela I. Mazaira ◽  
Alejandra G. Erlejman ◽  
Mario D. Galigniana
Keyword(s):  
Cancer Progression ◽  
Cancer Biology ◽  
Steroid Receptors ◽  
Human Cancer ◽  
Tumor Development ◽  
Biological Properties ◽  
Tetratricopeptide Repeats ◽  
Cellular Processes ◽  
Client Factors ◽  
Cancer Tissues

The identification of new factors that may function as cancer markers and become eventual pharmacologic targets is a challenge that may influence the management of tumor development and management. Recent discoveries connecting Hsp90-binding immunophilins with the regulation of signalling events that can modulate cancer progression transform this family of proteins in potential unconventional factors that may impact on the screening and diagnosis of malignant diseases. Immunophilins are molecular chaperones that group a family of intracellular receptors for immunosuppressive compounds. A subfamily of the immunophilin family is characterized by showing structural tetratricopeptide repeats, protein domains that are able to interact with the C-terminal end of the molecular chaperone Hsp90, and via the proper Hsp90-immunophilin complex, the biological properties of a number of client-proteins involved in cancer biology are modulated. Recent discoveries have demonstrated that two of the most studied members of this Hsp90- binding subfamily of immunophilins, FKBP51 and FKBP52, participate in several cellular processes such as apoptosis, carcinogenesis progression, and chemoresistance. While the expression levels of some members of the immunophilin family are affected in both cancer cell lines and human cancer tissues compared to normal samples, novel regulatory mechanisms have emerged during the last few years for several client-factors of immunophilins that are major players in cancer development and progression, among them steroid receptors, the transctiption factor NF-κB and the catalytic subunit of telomerase, hTERT. In this review, recent findings related to the biological properties of both iconic Hsp90-binding immunophilins, FKBP51 and FKBP52, are reviewed within the context of their interactions with those chaperoned client-factors. The potential roles of both immunophilins as potential cancer biomarkers and non-conventional pharmacologic targets for cancer treatment are discussed.

Role of molecular chaperones in steroid receptor action

2004 ◽  
Vol 40 ◽  
pp. 41-58 ◽  
Author(s):  
William B Pratt ◽  
Mario D Galigniana ◽  
Yoshihiro Morishima ◽  
Patrick J M Murphy
Keyword(s):  
Transcriptional Activation ◽  
Protein Trafficking ◽  
Steroid Receptors ◽  
Transcriptional Regulatory ◽  
Ubiquitin Proteasome ◽  
Proteasome Pathway ◽  
Receptor Action ◽  
Binding Cleft ◽  
Hsp 90

Unliganded steroid receptors are assembled into heterocomplexes with heat-shock protein (hsp) 90 by a multiprotein chaperone machinery. In addition to binding the receptors at the chaperone site, hsp90 binds cofactors at other sites that are part of the assembly machinery, as well as immunophilins that connect the assembled receptor-hsp90 heterocomplexes to a protein trafficking pathway. The hsp90-/hsp70-based chaperone machinery interacts with the unliganded glucocorticoid receptor to open the steroid-binding cleft to access by a steroid, and the machinery interacts in very dynamic fashion with the liganded, transformed receptor to facilitate its translocation along microtubular highways to the nucleus. In the nucleus, the chaperone machinery interacts with the receptor in transcriptional regulatory complexes after hormone dissociation to release the receptor and terminate transcriptional activation. By forming heterocomplexes with hsp90, the chaperone machinery stabilizes the receptor to degradation by the ubiquitin-proteasome pathway of proteolysis.

scholarly journals HSP90 Molecular Chaperones, Metabolic Rewiring, and Epigenetics: Impact on Tumor Progression and Perspective for Anticancer Therapy

Cells ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 532 ◽  
Author(s):  
Valentina Condelli ◽  
Fabiana Crispo ◽  
Michele Pietrafesa ◽  
Giacomo Lettini ◽  
Danilo Swann Matassa ◽  
...  
Keyword(s):  
Cancer Progression ◽  
Molecular Chaperones ◽  
Heat Shock Protein 90 ◽  
Anticancer Therapy ◽  
Cellular Functions ◽  
Master Regulators ◽  
Cellular Processes ◽  
Direct Binding ◽  
Client Proteins ◽  
The Relationship

Heat shock protein 90 (HSP90) molecular chaperones are a family of ubiquitous proteins participating in several cellular functions through the regulation of folding and/or assembly of large multiprotein complexes and client proteins. Thus, HSP90s chaperones are, directly or indirectly, master regulators of a variety of cellular processes, such as adaptation to stress, cell proliferation, motility, angiogenesis, and signal transduction. In recent years, it has been proposed that HSP90s play a crucial role in carcinogenesis as regulators of genotype-to-phenotype interplay. Indeed, HSP90 chaperones control metabolic rewiring, a hallmark of cancer cells, and influence the transcription of several of the key-genes responsible for tumorigenesis and cancer progression, through either direct binding to chromatin or through the quality control of transcription factors and epigenetic effectors. In this review, we will revise evidence suggesting how this interplay between epigenetics and metabolism may affect oncogenesis. We will examine the effect of metabolic rewiring on the accumulation of specific metabolites, and the changes in the availability of epigenetic co-factors and how this process can be controlled by HSP90 molecular chaperones. Understanding deeply the relationship between epigenetic and metabolism could disclose novel therapeutic scenarios that may lead to improvements in cancer treatment.

Targeting prostate cancer progenitor cells with telomerase interference: A novel therapeutic strategy

2009 ◽  
Vol 27 (15_suppl) ◽  
pp. e22029-e22029
Author(s):  
A. Goldkorn ◽  
T. Xu
Keyword(s):  
Gene Expression ◽  
Prostate Cancer ◽  
Progenitor Cells ◽  
Cancer Progression ◽  
Cell Activation ◽  
Telomerase Activity ◽  
Human Prostate ◽  
Telomerase Rna ◽  
Prostate Tumors

e22029 Background: We investigated whether telomerase, which is critical for benign stem cell activation, also plays a role in prostate cancer progenitor cells (PCPCs), which are thought to mediate therapy resistance and cancer progression, and we tested whether telomerase interference can effectively inhibit PCPC proliferation. Methods: A putative PCPC population was isolated from human prostatectomy specimens via collagen attachment and FACS selection for integrin α2β1 and CD44. PCPCs were characterized for gene expression (RT-PCR), clonogenicity (colony formation), invasiveness (matrigel chamber), and telomerase activity (qPCR-TRAP). PCPC telomerase interference was accomplished by lentiviral expression of 2 constructs: telomerase RNA with an altered template region (MT-Ter) and siRNA targeting wild-type telomerase RNA (anti-Ter siRNA). The effects of these constructs were assessed by measuring PCPC viability (MTS) and apoptosis (TUNEL assay). Results: An integrin α2β1+CD44+ putative PCPC population was isolated from 6 human prostate tumors. This population expressed high levels of “progenitor phenotype” genes (ABCG2, β-catenin, NANOG, Oct3/4) and low levels of “differentiated phenotype” genes (AR and PSA). PCPCs yielded >50 colonies per 1000 cells seeded on collagen after 3 weeks vs. none from FACS- cells, and matrigel chamber assay showed 10% of the PCPC population invading over 24 hours vs. none of the FACS- population. Most importantly, PCPCs possessed at least 20- fold greater telomerase activity than FACS- cells, and induction of telomerase interference in PCPCs via MT-hTer and anti- hTer siRNA expression elicited a brisk apoptotic response (TUNEL) by day 3 in >90% of cells, with concomitant near-complete growth inhibition (MTS). Conclusions: We have shown that human prostate tumors contain a subpopulation of prostate cancer progenitor cells (PCPCs) marked by an undifferentiated gene expression profile, vigorous clonogenicity and invasiveness, and high levels of telomerase activity that can be successfully exploited to neutralize these cells. Ongoing studies are investigating the in vivo effects of telomerase interference on PCPC tumorigenicity in mouse models. No significant financial relationships to disclose.

scholarly journals Derepression of hTERT gene expression promotes escape from oncogene-induced cellular senescence

2016 ◽  
Vol 113 (34) ◽  
pp. E5024-E5033 ◽  
Author(s):  
Priyanka L. Patel ◽  
Anitha Suram ◽  
Neena Mirani ◽  
Oliver Bischof ◽  
Utz Herbig
Keyword(s):  
Dna Damage ◽  
Cancer Progression ◽  
Ectopic Expression ◽  
Telomerase Activity ◽  
Early Event ◽  
Telomere Dysfunction ◽  
Telomeric Dna ◽  
Human Telomerase Reverse Transcriptase ◽  
Htert Gene ◽  
In Cells

Oncogene-induced senescence (OIS) is a critical tumor-suppressing mechanism that restrains cancer progression at premalignant stages, in part by causing telomere dysfunction. Currently it is unknown whether this proliferative arrest presents a stable and therefore irreversible barrier to cancer progression. Here we demonstrate that cells frequently escape OIS induced by oncogenic H-Ras and B-Raf, after a prolonged period in the senescence arrested state. Cells that had escaped senescence displayed high oncogene expression levels, retained functional DNA damage responses, and acquired chromatin changes that promoted c-Myc–dependent expression of the human telomerase reverse transcriptase gene (hTERT). Telomerase was able to resolve existing telomeric DNA damage response foci and suppressed formation of new ones that were generated as a consequence of DNA replication stress and oncogenic signals. Inhibition of MAP kinase signaling, suppressing c-Myc expression, or inhibiting telomerase activity, caused telomere dysfunction and proliferative defects in cells that had escaped senescence, whereas ectopic expression of hTERT facilitated OIS escape. In human early neoplastic skin and breast tissue, hTERT expression was detected in cells that displayed features of senescence, suggesting that reactivation of telomerase expression in senescent cells is an early event during cancer progression in humans. Together, our data demonstrate that cells arrested in OIS retain the potential to escape senescence by mechanisms that involve derepression of hTERT expression.

scholarly journals BRCA1 Inhibition of Telomerase Activity in Cultured Cells

2003 ◽  
Vol 23 (23) ◽  
pp. 8668-8690 ◽  
Author(s):  
Jingbo Xiong ◽  
Saijun Fan ◽  
Qinghui Meng ◽  
Laura Schramm ◽  
Chenguang Wang ◽  
...  
Keyword(s):  
Cell Lines ◽  
Cancer Progression ◽  
Cultured Cells ◽  
Brca1 Gene ◽  
Telomerase Activity ◽  
Breast Cancer Cell Lines ◽  
Suppressor Activity ◽  
Tert Promoter ◽  
Tumor Suppressor Activity

ABSTRACT Telomerase, an enzyme that maintains telomere length, plays major roles in cellular immortalization and cancer progression. We found that an exogenous BRCA1 gene strongly inhibited telomerase enzymatic activity in human prostate and breast cancer cell lines and caused telomere shortening in cell lines expressing wild-type BRCA1 (wtBRCA1) but not a tumor-associated mutant BRCA1 (T300G). wtBRCA1 inhibited the expression of the catalytic subunit (telomerase reverse transcriptase [TERT]) but had no effect on the expression of a subset of other components of the telomerase holoenzyme or on the expression of c-Myc, a transcriptional activator of TERT. However, endogenous BRCA1 associated and partially colocalized with c-Myc; exogenous wtBRCA1 strongly suppressed TERT promoter activity in various cell lines. The TERT inhibition was due, in part, to suppression of c-Myc E-box-mediated transcriptional activity. Suppression of TERT promoter and c-Myc activity required the amino terminus of BRCA1 but not the carboxyl terminus. Finally, endogenous BRCA1 and c-Myc were detected on transfected mouse and human TERT promoter segments in vivo. We postulate that inhibition of telomerase may contribute to the BRCA1 tumor suppressor activity.

scholarly journals Farnesylation of Ydj1 Is Required for In Vivo Interaction with Hsp90 Client Proteins

2008 ◽  
Vol 19 (12) ◽  
pp. 5249-5258 ◽  
Author(s):  
Gary A. Flom ◽  
Marta Lemieszek ◽  
Elizabeth A. Fortunato ◽  
Jill L. Johnson
Keyword(s):  
Molecular Chaperone ◽  
Steroid Receptors ◽  
Binding Domain ◽  
Zinc Binding ◽  
Physical Interaction ◽  
Client Proteins ◽  
Carboxy Terminal ◽  
Zinc Binding Domain ◽  
Substrate Binding Domain

Ydj1 of Saccharomyces cerevisiae is an abundant cytosolic Hsp40, or J-type, molecular chaperone. Ydj1 cooperates with Hsp70 of the Ssa family in the translocation of preproteins to the ER and mitochondria and in the maturation of Hsp90 client proteins. The substrate-binding domain of Ydj1 directly interacts with steroid receptors and is required for the activity of diverse Hsp90-dependent client proteins. However, the effect of Ydj1 alteration on client interaction was unknown. We analyzed the in vivo interaction of Ydj1 with the protein kinase Ste11 and the glucocorticoid receptor. Amino acid alterations in the proposed client-binding domain or zinc-binding domain had minor effects on the physical interaction of Ydj1 with both clients. However, alteration of the carboxy-terminal farnesylation signal disrupted the functional and physical interaction of Ydj1 and Hsp90 with both clients. Similar effects were observed upon deletion of RAM1, which encodes one of the subunits of yeast farnesyltransferase. Our results indicate that farnesylation is a major factor contributing to the specific requirement for Ydj1 in promoting proper regulation and activation of diverse Hsp90 clients.

scholarly journals Crosstalk between autophagy inhibitors and endosome-related secretory pathways: a challenge for autophagy-based treatment of solid cancers

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Martina Raudenska ◽  
Jan Balvan ◽  
Michal Masarik
Keyword(s):  
Cancer Progression ◽  
Protein Trafficking ◽  
Secretory Pathway ◽  
Clinical Results ◽  
Multivesicular Bodies ◽  
Cancer Type ◽  
Secretory Pathways ◽  
Specific Effects ◽  
Antineoplastic Treatment ◽  
Autophagy Inhibition

AbstractAutophagy is best known for its role in organelle and protein turnover, cell quality control, and metabolism. The autophagic machinery has, however, also adapted to enable protein trafficking and unconventional secretory pathways so that organelles (such as autophagosomes and multivesicular bodies) delivering cargo to lysosomes for degradation can change their mission from fusion with lysosomes to fusion with the plasma membrane, followed by secretion of the cargo from the cell. Some factors with key signalling functions do not enter the conventional secretory pathway but can be secreted in an autophagy-mediated manner.Positive clinical results of some autophagy inhibitors are encouraging. Nevertheless, it is becoming clear that autophagy inhibition, even within the same cancer type, can affect cancer progression differently. Even next-generation inhibitors of autophagy can have significant non-specific effects, such as impacts on endosome-related secretory pathways and secretion of extracellular vesicles (EVs). Many studies suggest that cancer cells release higher amounts of EVs compared to non-malignant cells, which makes the effect of autophagy inhibitors on EVs secretion highly important and attractive for anticancer therapy. In this review article, we discuss how different inhibitors of autophagy may influence the secretion of EVs and summarize the non-specific effects of autophagy inhibitors with a focus on endosome-related secretory pathways. Modulation of autophagy significantly impacts not only the quantity of EVs but also their content, which can have a deep impact on the resulting pro-tumourigenic or anticancer effect of autophagy inhibitors used in the antineoplastic treatment of solid cancers.

scholarly journals Structure of an Hsp90-immunophilin complex reveals cochaperone recognition of the client-maturation state

2021 ◽  
Author(s):  
Kanghyun Lee ◽  
Aye C. Thwin ◽  
Eric Tse ◽  
Stephanie N. Gates ◽  
Daniel R. Southworth
Keyword(s):  
Prolyl Isomerase ◽  
Ppiase Activity ◽  
Peptidyl Prolyl Isomerase ◽  
Recognition Element ◽  
Middle Domain ◽  
Ppiase Domain ◽  
Hsp90 Chaperone ◽  
Client Proteins ◽  
Maturation State ◽  
Tpr Domain

SummaryThe Hsp90 chaperone promotes the folding and activation of hundreds of client proteins in the cell through an ATP-dependent conformational cycle guided by distinct cochaperone regulators. The FKBP51 immunophilin binds Hsp90 with its tetratricopeptide repeat (TPR) domain and catalyzes peptidyl-prolyl isomerase (PPIase) activity during the folding of kinases, nuclear receptors and tau. Here we have determined the cryo-EM structure of the human Hsp90:FKBP51:p23 complex to 3.3 Å that, together with mutagenesis and crosslinking analysis, reveals the basis for cochaperone binding to Hsp90 during client maturation. A helix extension in the TPR functions as a key recognition element, interacting across the Hsp90 C-terminal dimer interface presented in the closed, ATP conformation. The PPIase domain is positioned along the middle domain, adjacent Hsp90 client binding sites, while a single p23 makes stabilizing interactions with the N-terminal dimer. With this architecture, FKBP51 could thereby act on specific client residues presented during Hsp90-catalyzed remodeling.

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