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Annual Review of Pathology Jan 2024Dystonia is a clinically and genetically highly heterogeneous neurological disorder characterized by abnormal movements and postures caused by involuntary sustained or... (Review)
Review
Dystonia is a clinically and genetically highly heterogeneous neurological disorder characterized by abnormal movements and postures caused by involuntary sustained or intermittent muscle contractions. A number of groundbreaking genetic and molecular insights have recently been gained. While they enable genetic testing and counseling, their translation into new therapies is still limited. However, we are beginning to understand shared pathophysiological pathways and molecular mechanisms. It has become clear that dystonia results from a dysfunctional network involving the basal ganglia, cerebellum, thalamus, and cortex. On the molecular level, more than a handful of, often intertwined, pathways have been linked to pathogenic variants in dystonia genes, including gene transcription during neurodevelopment (e.g., , ), calcium homeostasis (e.g., , ), striatal dopamine signaling (e.g., ), endoplasmic reticulum stress response (e.g., , , ), autophagy (e.g., ), and others. Thus, different forms of dystonia can be molecularly grouped, which may facilitate treatment development in the future.
Topics: Humans; Dystonia; Dystonic Disorders; Dopamine; Molecular Chaperones; DNA-Binding Proteins; Apoptosis Regulatory Proteins; Anoctamins
PubMed: 37738511
DOI: 10.1146/annurev-pathmechdis-051122-110756 -
Science (New York, N.Y.) Aug 2023The discovery of small-molecule inhibitors requires suitable binding pockets on protein surfaces. Proteins that lack this feature are considered undruggable and require...
The discovery of small-molecule inhibitors requires suitable binding pockets on protein surfaces. Proteins that lack this feature are considered undruggable and require innovative strategies for therapeutic targeting. is the most frequently activated oncogene in cancer, and the active state of mutant KRAS is such a recalcitrant target. We designed a natural product-inspired small molecule that remodels the surface of cyclophilin A (CYPA) to create a neomorphic interface with high affinity and selectivity for the active state of KRAS (in which glycine-12 is mutated to cysteine). The resulting CYPA:drug:KRAS tricomplex inactivated oncogenic signaling and led to tumor regressions in multiple human cancer models. This inhibitory strategy can be used to target additional KRAS mutants and other undruggable cancer drivers. Tricomplex inhibitors that selectively target active KRAS or multiple RAS mutants are in clinical trials now (NCT05462717 and NCT05379985).
Topics: Humans; Biological Products; Cysteine; Molecular Chaperones; Proto-Oncogene Proteins p21(ras); Signal Transduction; Cyclophilin A; Immunophilins; Neoplasms
PubMed: 37590355
DOI: 10.1126/science.adg9652 -
Proceedings of the National Academy of... Aug 2023Cancer cells are commonly subjected to endoplasmic reticulum (ER) stress. To gain survival advantage, cancer cells exploit the adaptive aspects of the unfolded protein...
Cancer cells are commonly subjected to endoplasmic reticulum (ER) stress. To gain survival advantage, cancer cells exploit the adaptive aspects of the unfolded protein response such as upregulation of the ER luminal chaperone GRP78. The finding that when overexpressed, GRP78 can escape to other cellular compartments to gain new functions regulating homeostasis and tumorigenesis represents a paradigm shift. Here, toward deciphering the mechanisms whereby GRP78 knockdown suppresses transcription, we find that nuclear GRP78 is prominent in cancer and stressed cells and uncover a nuclear localization signal critical for its translocation and nuclear activity. Furthermore, nuclear GRP78 can regulate expression of genes and pathways, notably those important for cell migration and invasion, by interacting with and inhibiting the activity of the transcriptional repressor ID2. Our study reveals a mechanism for cancer cells to respond to ER stress via transcriptional regulation mediated by nuclear GRP78 to adopt an invasive phenotype.
Topics: Humans; Endoplasmic Reticulum Chaperone BiP; Cell Nucleus; Carcinogenesis; Cell Movement; Cell Transformation, Neoplastic
PubMed: 37487081
DOI: 10.1073/pnas.2303448120 -
Brain : a Journal of Neurology Aug 2023In the field of rare diseases, progress in molecular diagnostics led to the recognition that variants linked to autosomal-dominant neurodegenerative diseases of later...
In the field of rare diseases, progress in molecular diagnostics led to the recognition that variants linked to autosomal-dominant neurodegenerative diseases of later onset can, in the context of biallelic inheritance, cause devastating neurodevelopmental disorders and infantile or childhood-onset neurodegeneration. TOR1A-associated arthrogryposis multiplex congenita 5 (AMC5) is a rare neurodevelopmental disorder arising from biallelic variants in TOR1A, a gene that in the heterozygous state is associated with torsion dystonia-1 (DYT1 or DYT-TOR1A), an early-onset dystonia with reduced penetrance. While 15 individuals with AMC5-TOR1A have been reported (less than 10 in detail), a systematic investigation of the full disease-associated spectrum has not been conducted. Here, we assess the clinical, radiological and molecular characteristics of 57 individuals from 40 families with biallelic variants in TOR1A. Median age at last follow-up was 3 years (0-24 years). Most individuals presented with severe congenital flexion contractures (95%) and variable developmental delay (79%). Motor symptoms were reported in 79% and included lower limb spasticity and pyramidal signs, as well as gait disturbances. Facial dysmorphism was an integral part of the phenotype, with key features being a broad/full nasal tip, narrowing of the forehead and full cheeks. Analysis of disease-associated manifestations delineated a phenotypic spectrum ranging from normal cognition and mild gait disturbance to congenital arthrogryposis, global developmental delay, intellectual disability, absent speech and inability to walk. In a subset, the presentation was consistent with foetal akinesia deformation sequence with severe intrauterine abnormalities. Survival was 71%, with higher mortality in males. Death occurred at a median age of 1.2 months (1 week-9 years), due to respiratory failure, cardiac arrest or sepsis. Analysis of brain MRI studies identified non-specific neuroimaging features, including a hypoplastic corpus callosum (72%), foci of signal abnormality in the subcortical and periventricular white matter (55%), diffuse white matter volume loss (45%), mega cisterna magna (36%) and arachnoid cysts (27%). The molecular spectrum included 22 distinct variants, defining a mutational hotspot in the C-terminal domain of the Torsin-1A protein. Genotype-phenotype analysis revealed an association of missense variants in the 3-helix bundle domain to an attenuated phenotype, while missense variants near the Walker A/B motif as well as biallelic truncating variants were linked to early death. In summary, this systematic cross-sectional analysis of a large cohort of individuals with biallelic TOR1A variants across a wide age-range delineates the clinical and genetic spectrum of TOR1A-related autosomal-recessive disease and highlights potential predictors for disease severity and survival.
Topics: Male; Humans; Cross-Sectional Studies; Mutation; Phenotype; Dystonia; Dystonic Disorders; Nervous System Malformations; Molecular Chaperones
PubMed: 36757831
DOI: 10.1093/brain/awad039 -
Cell Death & Disease Jul 2023Chemoresistance is one of the major causes of therapeutic failure and poor prognosis for breast cancer patients, especially for triple-negative breast cancer patients....
Chemoresistance is one of the major causes of therapeutic failure and poor prognosis for breast cancer patients, especially for triple-negative breast cancer patients. However, the underlying mechanism remains elusive. Here, we identified novel functional roles of heat shock protein beta-1 (HSPB1), regulating chemoresistance and ferroptotic cell death in breast cancer. Based on TCGA and GEO databases, HSPB1 expression was upregulated in breast cancer tissues and associated with poor prognosis of breast cancer patients, which was considered an independent prognostic factor for breast cancer. Functional assays revealed that HSPB1 could promote cancer growth and metastasis in vitro and in vivo. Furthermore, HSPB1 facilitated doxorubicin (DOX) resistance through protecting breast cancer cells from drug-induced ferroptosis. Mechanistically, HSPB1 could bind with Ikβ-α and promote its ubiquitination-mediated degradation, leading to increased nuclear translocation and activation of NF-κB signaling. In addition, HSPB1 overexpression led to enhanced secretion of IL6, which further facilitated breast cancer progression. These findings revealed that HSPB1 upregulation might be a key driver to progression and chemoresistance through regulating ferroptosis in breast cancer while targeting HSPB1 could be an effective strategy against breast cancer.
Topics: Humans; Female; NF-kappa B; Breast Neoplasms; HSP27 Heat-Shock Proteins; Drug Resistance, Neoplasm; Signal Transduction; Cell Death; Triple Negative Breast Neoplasms; Cell Line, Tumor; Heat-Shock Proteins; Molecular Chaperones
PubMed: 37454220
DOI: 10.1038/s41419-023-05972-0 -
Cell Reports Dec 2023Chaperone-mediated autophagy (CMA) and endosomal microautophagy (eMI) are pathways for selective degradation of cytosolic proteins in lysosomes and late endosomes,...
Chaperone-mediated autophagy (CMA) and endosomal microautophagy (eMI) are pathways for selective degradation of cytosolic proteins in lysosomes and late endosomes, respectively. These autophagic processes share as a first step the recognition of the same five-amino-acid motif in substrate proteins by the Hsc70 chaperone, raising the possibility of coordinated activity of both pathways. In this work, we show the existence of a compensatory relationship between CMA and eMI and identify a role for the chaperone protein Bag6 in triage and internalization of eMI substrates into late endosomes. Association and dynamics of Bag6 at the late endosome membrane change during starvation, a stressor that, contrary to other autophagic pathways, causes a decline in eMI activity. Collectively, these results show a coordinated function of eMI with CMA, identify the interchangeable subproteome degraded by these pathways, and start to elucidate the molecular mechanisms that facilitate the switch between them.
Topics: Chaperone-Mediated Autophagy; Microautophagy; Autophagy; Endosomes; Lysosomes; Molecular Chaperones
PubMed: 38060380
DOI: 10.1016/j.celrep.2023.113529 -
Nature Communications Aug 2023Molecular chaperone HSP70s are attractive targets for cancer therapy, but their substrate broadness and functional non-specificity have limited their role in...
Molecular chaperone HSP70s are attractive targets for cancer therapy, but their substrate broadness and functional non-specificity have limited their role in therapeutical success. Functioning as HSP70's cochaperones, HSP40s determine the client specificity of HSP70s, and could be better targets for cancer therapy. Here we show that tumors defective in HSP40 member DNAJA2 are benefitted from immune-checkpoint blockade (ICB) therapy. Mechanistically, DNAJA2 maintains centrosome homeostasis by timely degrading key centriolar satellite proteins PCM1 and CEP290 via HSC70 chaperone-mediated autophagy (CMA). Tumor cells depleted of DNAJA2 or CMA factor LAMP2A exhibit elevated levels of centriolar satellite proteins, which causes aberrant mitosis characterized by abnormal spindles, chromosome missegregation and micronuclei formation. This activates the cGAS-STING pathway to enhance ICB therapy response in tumors derived from DNAJA2-deficient cells. Our study reveals a role for DNAJA2 to regulate mitotic division and chromosome stability and suggests DNAJA2 as a potential target to enhance cancer immunotherapy, thereby providing strategies to advance HSPs-based cancer therapy.
Topics: Humans; Mitosis; Cell Nucleus Division; Chromogranin A; Nucleotidyltransferases; Chromosomal Instability; HSP70 Heat-Shock Proteins; HSP40 Heat-Shock Proteins
PubMed: 37640708
DOI: 10.1038/s41467-023-40952-0 -
Autophagy Dec 2023aa: amino acid; ATF6: activating transcription factor 6; ATG5: autophagy related 5; CCPG1: cell cycle progression 1; CFTR: CF transmembrane conductance regulator; cGAMP:...
aa: amino acid; ATF6: activating transcription factor 6; ATG5: autophagy related 5; CCPG1: cell cycle progression 1; CFTR: CF transmembrane conductance regulator; cGAMP: cyclic GMP-AMP; CGAS: cyclic GMP-AMP synthase; CHX: cycloheximide; Co-IP: co-immunoprecipitation; CQ: chloroquine; EIF2A/eIF2α: eukaryotic translation initiation factor 2A; EIF2AK3/PERK: eukaryotic translation initiation factor 2 alpha kinase 3; ER: endoplasmic reticulum; ERN1/IRE1: endoplasmic reticulum to nucleus signaling 1; GFP: green fluorescent protein; HSPA5/GRP78: heat shock protein family A (Hsp70) member 5; HSV-1: herpes simplex virus type 1; IFIT1: interferon induced protein with tetratricopeptide repeats 1; IFNB1/IFN-β: interferon beta 1; IRF3: interferon regulatory factor 3; ISG15: ISG15 ubiquitin like modifier; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MAP3K7/TAK1: mitogen-activated protein kinase kinase kinase 7; MAVS: mitochondrial antiviral signaling protein; MOI: multiplicity of infection; NFKB/NF-κB: nuclear factor kappa B; NSP6: non-structural protein 6; Δ106-108: deletion of amino acids 106-108 in NSP6 of SARS-CoV-2; Δ105-107: deletion of amino acids 105-107 in NSP6 of SARS-CoV-2; RETREG1/FAM134B: reticulophagy regulator 1; RIGI/DDX58: RNA sensor RIG-I; SQSTM1/p62: sequestosome 1; STING1: stimulator of interferon response cGAMP interactor 1; TBK1: TANK binding kinase 1.
Topics: Humans; SARS-CoV-2; Autophagy; COVID-19; Endoplasmic Reticulum Stress; Endoplasmic Reticulum Chaperone BiP; Interferons; Amino Acids
PubMed: 37482689
DOI: 10.1080/15548627.2023.2238579 -
Nature Communications Aug 2023SMNDC1 is a Tudor domain protein that recognizes di-methylated arginines and controls gene expression as an essential splicing factor. Here, we study the specific...
SMNDC1 is a Tudor domain protein that recognizes di-methylated arginines and controls gene expression as an essential splicing factor. Here, we study the specific contributions of the SMNDC1 Tudor domain to protein-protein interactions, subcellular localization, and molecular function. To perturb the protein function in cells, we develop small molecule inhibitors targeting the dimethylarginine binding pocket of the SMNDC1 Tudor domain. We find that SMNDC1 localizes to phase-separated membraneless organelles that partially overlap with nuclear speckles. This condensation behavior is driven by the unstructured C-terminal region of SMNDC1, depends on RNA interaction and can be recapitulated in vitro. Inhibitors of the protein's Tudor domain drastically alter protein-protein interactions and subcellular localization, causing splicing changes for SMNDC1-dependent genes. These compounds will enable further pharmacological studies on the role of SMNDC1 in the regulation of nuclear condensates, gene regulation and cell identity.
Topics: Aptamers, Nucleotide; Biomolecular Condensates; Carbocyanines; Nuclear Speckles; SMN Complex Proteins; Tudor Domain
PubMed: 37587144
DOI: 10.1038/s41467-023-40124-0 -
Cell Stress & Chaperones Jun 2024More than 99% of the mitochondrial proteome is encoded by the nucleus and requires refolding following import. Therefore, mitochondrial proteins require the coordinated... (Review)
Review
More than 99% of the mitochondrial proteome is encoded by the nucleus and requires refolding following import. Therefore, mitochondrial proteins require the coordinated action of molecular chaperones for their folding and activation. Several heat shock protein (Hsp) molecular chaperones, including members of the Hsp27, Hsp40/70, and Hsp90 families, as well as the chaperonin complex Hsp60/10 have an established role in mitochondrial protein import and folding. The "Chaperone Code" describes the regulation of chaperone activity by dynamic post-translational modifications; however, little is known about the post-translational regulation of mitochondrial chaperones. Dissecting the regulation of chaperone function is essential for understanding their differential regulation in pathogenic conditions and the potential development of efficacious therapeutic strategies. Here, we summarize the recent literature on post-translational regulation of mitochondrial chaperones, the consequences for mitochondrial function, and potential implications for disease.
Topics: Humans; Mitochondria; Molecular Chaperones; Mitochondrial Proteins; Animals; Protein Processing, Post-Translational; Heat-Shock Proteins; Protein Folding
PubMed: 38763405
DOI: 10.1016/j.cstres.2024.05.002