A novel nuclear DnaJ protein, DNAJC8, can suppress the formation of spinocerebellar ataxia 3 polyglutamine aggregation in a J-domain independent manner
Introduction
Polyglutamine (polyQ) diseases are a group of familial neurodegenerative disorders, and nine diseases including Huntington's disease and six types of spinocerebellar ataxia (SCA), have been described for which the common mutation is a CAG trinucleotide expansion [1]. All these disorders, excepting spinal bulbar muscular atrophy, are dominantly inherited, progressive, usually begin in mid-life, and result in severe neuronal dysfunction and neuronal cell death in the selective region of the brain [2]. Misfolding and aggregation of polyQ-containing disease proteins is thought to be critical to pathogenesis. The molecular mechanisms by which the proteins implicated in the polyQ diseases aggregate are still unknown. Recent studies suggest that the age-dependent accumulation of the protein aggregates in neurodegenerative diseases reflects the progressive inability of the cellular quality control machinery to recognize and eliminate potentially toxic misfolded proteins. This raises the possibility that the cellular machinery for protein quality control may play an important role in polyQ disease.
Cellular machinery for protein quality control is constituted by a group of specialized proteins, known as heat shock proteins (HSPs), which promote the folding and assembly of mature protein complexes. There are several numbers of HSP families and they include HSPH (HSP110), HSPC (HSP90), HSPA (HSP70), DNAJ (HSP40) and HSPB (small HSP) familes [3]. The most abundant family of HSP consists of the highly conserved 70-kDa heat shock proteins (HSP70), which were shown to be essential in numerous cellular processes. The apparent discrepancy between the broad substrate specificity of HSP70 on one hand and the high specialization of HSP70 function on the other has been explained by the discovery that HSP70 work in concert with partner co-chaperones, DNAJ proteins [4]. DNAJ proteins, as opposed to HSP70, constitute a heterogeneous group of multi-domain proteins defined by the highly conserved J-domain, which are necessary to stimulate ATPase activity of interacting HSP70 [5], [6]. And the heterogeneity of DNAJ proteins defines diversity of functional properties of HSP70, and DNAJ family proteins have broad biological functions [7], [8], [9], [10], [11]. Recent studies reveled that DNAJ proteins have roles in suppression of protein aggregation formation [12], [13], [14].
In the present study, we focused on nuclear DNAJ proteins, since polyQ aggregates are formed inside the nucleus in most polyQ diseases [15], and analyzed a novel DNAJ protein, DNAJC8.
Section snippets
Cell culture and transfection
A neuroblastoma cell line SH-SY5Y and a cervical carcinoma cell line HeLa were purchased from american type culture collection (ATCC; Manassas, VA, USA) and maintained. Plasmid transfection was performed by using Lipofectamine 2000 reagent (Thermo Fisher Scientific) according to the manufacture's protocol. For stable transfection, puromycin (3.5 μg/ml; Sigma–Aldrich, St Louis, MO, USA) was added to culture medium 48 h after transfection. For confocal microscopy, the cells were transferred into
Structure and gene expression of DNAJC8 protein
To identify a protein that is localized in the nucleus and contains J-domain, we searched the human expressed sequence tag (EST) database. We found a large number of proteins that contain amino acid sequences with similarity to J-domain of HSP40 (Caenorhabditis elegans). A DNAJ proteins, DNAJC8 was identified to contain nuclear localization signals [6] (Fig. 1A). DNAJC8 has the canonical J-domain (residue 68–127) including the conserved tripeptide, His-Pro-Asp, and the 50th Ala residue
Discussion
Nine neurodegenerative diseases have been known as polyglutamine diseases, in which certain proteins with polyQ repeat expansion forms aggregation and deposition in neuronal cells. The polyQ aggregates have neurotoxic property, therefore leading to neuronal dysfunction, degeneration and cell death. Though the precise mechanism of the aggregate formation in each polyQ-containing disease protein has not been well defined, polyQ expansion is thought to cause a conformational change that promotes
Declaration of financial disclosure
The authors have no financial conflict of interest.
Acknowledgment
We thank Dr. Takeshi Urano and Dr. Itaru Hirai for helpful discussions. This study was supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology of Japan (grant no. 15H04722) (to T. T., Y. H. and N. S.) and program for developing the supporting system for upgrading education and research from the Ministry of Education, Culture, Sports, Science and Technology of Japan (to N. S.). This study was supported in part by Grants-in-Aid
References (28)
- et al.
PolyQ disease: misfiring of a developmental cell death program?
Trends Cell Biol.
(2013) Polyglutamine neurodegeneration: expanded glutamines enhance native functions
Curr. Opin. Genet. Dev.
(2012)- et al.
Guidelines for the nomenclature of the human heat shock proteins
Cell Stress Chaperones
(2009) The J-domain family and the recruitment of chaperone power
Trends Biochem. Sci.
(1998)- et al.
A DNAJB chaperone subfamily with HDAC-dependent activities suppresses toxic protein aggregation
Mol. Cell
(2010) - et al.
The DNAJB6 and DNAJB8 protein chaperones prevent intracellular aggregation of polyglutamine peptides
J. Biol. Chem.
(2013) - et al.
Membrane filter assay for detection of amyloid-like polyglutamine-containing protein aggregates
Methods Enzymol.
(1999) - et al.
Cellular toxicity of polyglutamine expansion proteins: mechanism of transcription factor deactivation
Mol. Cell
(2004) - et al.
Mammalian HSP40/DNAJ homologs: cloning of novel cDNAs and a proposal for their classification and nomenclature
Cell Stress Chaperones
(2000) - et al.
Molecular chaperone function of mammalian Hsp70 and Hsp40–a review
Int. J. Hyperth.
(2000)
The diversity of the DnaJ/Hsp40 family, the crucial partners for Hsp70 chaperones
Cell Mol. Life Sci.
The HSP70 chaperone machinery: J proteins as drivers of functional specificity
Nat. Rev. Mol. Cell Biol.
HSP DNAJB8 controls tumor-initiating ability in renal cancer stem-like cells
Cancer Res.
Heat shock protein DNAJB8 is a novel target for immunotherapy of colon cancer-initiating cells
Cancer Sci.
Cited by (22)
Specific serum autoantibodies predict the development and progression of Alzheimer's disease with high accuracy
2024, Brain, Behavior, and ImmunityJ-domain proteins interaction with neurodegenerative disease-related proteins
2021, Experimental Cell ResearchCitation Excerpt :Three NLS-labelled synthetic peptides corresponding to DNAJC8 C-terminal amino acids 216–228, 229–242 and 243–265 revealed that the C-terminal 22 residues of DNAJC8 (243–265) exhibit the highest anti-aggregation activity, although lower in comparison to that of the complete protein. Interestingly, peptide 243–265 contained the highest amount of positively charged and aromatic residues in comparison to the other two synthetic peptides, suggesting that charged and aromatic amino acids are involved in the binding of SCA82Q [63]. Second, very recently it could be demonstrated that DNAJC7 binds to natively folded tau protein and suppresses its aggregation in vitro and in cells [64].
Analyses of the function of DnaJ family proteins reveal an underlying regulatory mechanism of heat tolerance in honeybee
2020, Science of the Total EnvironmentCitation Excerpt :Knowledge of the subcellular localization characteristics of a protein will contribute to better understanding of its possible location when functional. In humans, it was proven that DnaJA1, DnaJB12 and DnaJC8 are a cytoplasmic protein, transmembrane protein and nuclear protein, respectively (Goodwin et al., 2014; Ito et al., 2016; Qiu et al., 2006). We found that DnaJA1 and DnaJB12 accumulated in the cytoplasm, and DnaJC8 was located in the nucleus in A. c. cerana (Fig. 2A).
Pathogenesis of SCA3 and implications for other polyglutamine diseases
2020, Neurobiology of DiseaseCitation Excerpt :These studies reveal the therapeutic potential for Hsp90 inhibitors via a HSF1-dependent mechanism in SCA3 and perhaps other polyQ diseases. More recently DNAJC8 (Ito et al., 2016), HSPB7 (Wu et al., 2019), and the novel Dictyostelium chaperone, SRCP1 (Santarriaga et al., 2015; Santarriaga et al., 2018) have been described as potential chaperone regulators of the early polyQ aggregation steps. While there is strong evidence for pathogenic dysregulation of HSF1 and downstream chaperones in many neurodegenerative diseases, including HD, Alzheimer’s Disease and Parkinson’s disease (Gomez-Pastor et al., 2018), further testing in vertebrate SCA3 animal models of HSF1 activators and novel chaperones that directly impede polyQ aggregation will be required to determine the therapeutic utility of chaperone treatments.
Experimental and Clinical Strategies for Treating Spinocerebellar Ataxia Type 3
2018, NeuroscienceCitation Excerpt :Furthermore, the co-chaperone and ubiquitin ligase C-terminus of Hsp70-interacting protein (CHIP), which represents an important player in protein homeostasis, was shown to counteract mutant atx-3 toxicity and aggregation (Williams et al., 2009). Recent work demonstrated that a novel nuclear protein, namely DNAJC8 (DNAJ (HSP40) 6 Homolog, Subfamily C, Member 8) prevents atx-3 aggregate formation by a mechanism independent of HSP70 chaperone machinery (Ito et al., 2016). The chaperone DNAJB6 was also shown to inhibit polyQ aggregation, which suggests DNAJB6 is another target of interest for SCA3/MJD therapy (Kakkar et al., 2016).
Polyglutamine expansion diseases: More than simple repeats
2018, Journal of Structural Biology