Biosynthesis and secretion of mouse cysteine‐rich with EGF‐like domains 2

Biological & Pharmaceutical Bulletin

Norisada

Hirata

et al. 2015

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We recently demonstrated that the secretion of two novel endoplasmic reticulum (ER) stress-inducible proteins, cysteine-rich with epidermal growth factor (EGF)-like domains 2 (CRELD2) and mesencephalic astrocyte-derived neurotrophic factor (MANF), are oppositely regulated by the overexpression of 78 kDa glucose-regulated protein (GRP78). In the present study, we found that the co-transfection of CRELD2 and MANF remarkably enhanced the secretion of CRELD2 without affecting the expression level of GRP78. To identify the structural features of CRELD2 and MANF involved in this process, we generated several CRELD2 and MANF expression constructs. The deletion of the four C-terminal amino acids, either REDL in CRELD2 or RTDL in MANF, abolished the increased secretion of CRELD2 induced by the co-expression of MANF. The deleted mutation of MANF partially abolished the increased secretion of wild type CRELD2 (wtCRELD2) as a positive action of wild type MANF (wtMANF), even when we added the amino acid sequence RTDL at the C-terminus of each mutated MANF construct. Enhanced green fluorescent protein (EGFP), which was tagged with the signal peptide sequence at the N-terminus and four C-terminal amino acids (KEDL, REDL or RTDL), were retained intracellularly, but they did not enhance the secretion of wtCRELD2. Taken together, our data demonstrate that MANF is a factor in regulating the secretion of CRELD2 through four C-terminal amino acids, RTDL and REDL, and the fluctuation of intracellular MANF seems to potentiate the secretion of CRELD2.Key words endoplasmic reticulum; chaperone; 78 kDa glucose-regulated protein (GRP78); cysteine-rich with epidermal growth factor (EGF)-like domains 2 (CRELD2); mesencephalic astrocyte-derived neurotrophic factor (MANF)The folding and modification of newly synthesized transmembrane and secretory proteins in the endoplasmic reticulum (ER) is maintained by a variety of mechanisms.1,2) Under some pathophysiological conditions, certain ER functions become disordered and then unfolded and/or misfolded proteins are accumulated in the ER.3,4) Abnormal protein retention results in ER stress and activation of the three canonical ERresident stress sensors; protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK), 5) inositol-requiring enzyme 1 (IRE1) 6) and activating transcription factor 6 (ATF6), 7) induces a variety of genes.8-12) Among them, growth arrest and DNA damage-inducible protein 153 (GADD153) is well-known to promote stress-induced cell death by activating caspases. 8,9) ER resident molecular chaperones such as 78 kDa glucoseregulated protein (GRP78) are reported to alleviate the stress by properly folding and degrading unfolded proteins and attenuating ER stress signals. 10,11) We previously identified the cysteine-rich with epidermal growth factor (EGF)-like domains 2 (CRELD2) gene as a novel ER stress-inducible gene and demonstrate that ATF6 positively regulates the transcription of the CRELD2 gene through a well-conserved ER stress response element (ERSE) in the proximal regio...

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confidence: 74%

“…Furthermore, we have characterized the intracellular traffic and secretion of CRELD2 13,14) ; however, the precise functions of the CRELD2 protein remain to be determined.…”

Section: )mentioning

confidence: 99%

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confidence: 99%

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Characterization of the Role of MANF in Regulating the Secretion of CRELD2

Biological & Pharmaceutical Bulletin

Norisada

Hirata

et al. 2015

Self Cite

“…We recently demonstrated that the ERSE motif located within the 360-bp intergenic region asymmetrically participates in the activation of the CRELD2 promoter in response to ER stress or ATF6-overexpression [8]. We also reported on the molecular features of CRELD2 as a novel ER stress-inducible secretory factor [8][9][10]. However, the precise functions of CRELD2 in the intra-and extracellular spaces remain to be determined [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

“…We also reported on the molecular features of CRELD2 as a novel ER stress-inducible secretory factor [8][9][10]. However, the precise functions of CRELD2 in the intra-and extracellular spaces remain to be determined [9][10][11]. It is unclear whether there is any functional relationship between CRELD2 and ALG12 as ER stress-inducible genes.…”

Section: Introductionmentioning

confidence: 99%

Characterization of the 5′-flanking region of the mouse asparagine-linked glycosylation 12 homolog gene

Cellular and Molecular Biology Letters

Hirata³

et al. 2013

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Recently, we characterized multiple roles of the endoplasmic reticulum stress responsive element (ERSE) in the promotion of a unique headto-head gene pair: mammalian asparagine-linked glycosylation 12 homolog (ALG12) and cysteine-rich with EGF-like domains 2 (CRELD2). This bidirectional promoter, which consists of fewer than 400 base pairs, separates the two genes. It has been demonstrated that the ALG12 promoter shows less transcriptional activity through ERSE, but its basic regulatory mechanism has not been characterized. In this study, we focused on well-conserved binding elements for the transcription factors for ATF6, NF-Y and YY1 and the Sp1 and Ets families in the 5’-flanking region of the mouse ALG12 gene. We characterized their dominant roles in regulating ALG12 promoter activities using several deletion and mutation luciferase reporter constructs. The ALG12 gene is expressed in three distinct cell lines: Neuro2a, C6 glioma and HeLa cells. The reporter activity in each cell line decreased similarly with serial deletions of the mouse ALG12 promoter. Mutations in the ERSE and adjacent NF-Y-binding element slightly affected reporter activity. Each of the mutations in the GC-rich sequence and YY1-binding element reduced ALG12 promoter activity, and the combination of these mutations additively decreased reporter activity. Each mutation in the tandem-arranged Ets-family consensus sequences partially attenuated ALG12 promoter activity, and mutations of all three Ets-binding elements decreased promoter activity by approximately 40%. Mutation of the three conserved regulatory elements (GC-rich, YY1 and Ets) in the ALG12 promoter decreased reporter activity by more than 90%. Our results suggest that the promoter activity of the mouse ALG12 gene is regulated in a similar manner in the three cell lines tested in this study. The well-conserved consensus sequences in the promoter of this gene synergistically contribute to maintaining basal gene expression.

SOD1 dimerization monitoring using a novel split NanoLuc, NanoBit

Cell Biochemistry & Function

Hirata

Kiuchi

2016

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In the present study, we applied a highly sensitive NanoLuc-based technology to understand the status of superoxide dismutase 1 (SOD1) within mammalian cells. Two fragments of NanoLuc (NanoBit), large N-terminal and small C-terminal regions, were fused with wild-type (wt) and mutant human SOD1 (hSOD1) genes and transfected into cells. Luciferase activity through NanoBit assembly was only detected in NanoBit-tagged wtSOD1-expressing cells. Furthermore, the developed NanoLuc system was used to investigate the role of protein-protein interactions in the pathogenesis of amyotrophic lateral sclerosis (ALS). In addition to SOD1, we also applied this NanoBit system for detecting the dimerization of wild-type, M337V-mutated human TAR-binding protein 43 kDa (hTDP43) and its cleaved C-terminal fragment (TDP25 ) as well as their interactions with SOD1. Luciferase activities of NanoBit-tagged mutant SOD1, TDP43, or TDP25 were negligible. Finally, we found that a zinc chelator partially reduced the luciferase activity of NanoBit-wtSOD1. Collectively, these results show that the present assay is sensitive and convenient to appreciate ALS and to develop useful agents for the modulation of SOD1 conformation.