1
|
Yadav MP, Narayanasamy S, Aradhyam GK. Structural Plasticity Allows Calumenin-1 to Moonlight as a Ca 2+-Independent Chaperone: Pb 2+ Enables Probing Alternate Inhibitory Conformation. Biochemistry 2024; 63:69-81. [PMID: 38100476 DOI: 10.1021/acs.biochem.3c00326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2023]
Abstract
Human calumenin-1 (HsCalu-1) is an endoplasmic reticulum (ER) and Golgi-resident Ca2+-binding protein of the hepta-EF-hand superfamily that plays a vital role in maintaining the cytoplasmic Ca2+ concentration below toxic levels by interacting with Sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) and ryanodine receptors (RyR), indicating its role in Ca2+ homeostasis in the ER. HsCalu-1 seems to be able to exhibit structural plasticity to achieve its plethora of functions. In this study, we demonstrate that HsCalu-1 acts as a chaperone in both its intrinsically disordered state (apo form) and the structured state (Ca2+-bound form). HsCalu-1 chaperone activity is independent of Ca2+ and Pb2+ binding attenuating its chaperone-like activity. Incidentally, Pb2+ binds to HsCalu-1 with lower affinity (KD = 38.46 μM) (compared to Ca2+-binding), leading to the formation of a less-stable conformation as observed by a sharp drop in its melting temperature Tm from 67 °C in the Ca2+-bound form to 43 °C in the presence of Pb2+. The binding site for Pb2+ was mapped as being in the EF-Hand-234 domain of HsCalu-1, a region that overlaps with the Ca2+-dependent initiator of its functional fold. A change in the secondary and tertiary structure, leading to a less-stable but compact conformation upon Pb2+ binding, is the mechanism by which the chaperone-like activity of HsCalu-1 is diminished. Our results not only demonstrate the chaperone activity by a protein in its disordered state but also explain, using Pb2+ as a probe, that the multiple functions of calumenin are due to its ability to adopt a quasi-stable conformation.
Collapse
Affiliation(s)
- Manoj Padamsing Yadav
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
| | - Sasirekha Narayanasamy
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
| | - Gopala Krishna Aradhyam
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
| |
Collapse
|
2
|
Mikhaylina A, Svoeglazova A, Stolboushkina E, Tishchenko S, Kostareva O. The RNA-Binding and RNA-Melting Activities of the Multifunctional Protein Nucleobindin 1. Int J Mol Sci 2023; 24:ijms24076193. [PMID: 37047165 PMCID: PMC10093973 DOI: 10.3390/ijms24076193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/21/2023] [Accepted: 03/21/2023] [Indexed: 03/29/2023] Open
Abstract
Nucleobindin 1 (NUCB1) is a ubiquitous multidomain protein that belongs to the EF-hand Ca2+-binding superfamily. NUCB1 interacts with Galphai3 protein, cyclooxygenase, amyloid precursor protein, and lipids. It is involved in stress response and human diseases. In addition, this protein is a transcription factor that binds to the DNA E-box motif. Using surface plasmon resonance and molecular beacon approaches, we first showed the RNA binding and RNA melting activities of NUCB1. We suggest that NUCB1 could induce local changes in structured RNAs via binding to the GGAUAU loop sequence. Our results demonstrate the importance of the multidomain structure of NUCB1 for its RNA-chaperone activity in vitro.
Collapse
|
3
|
Yan R, Chen K, Wang B, Xu K. SURF4-induced tubular ERGIC selectively expedites ER-to-Golgi transport. Dev Cell 2022; 57:512-525.e8. [PMID: 35051356 PMCID: PMC8891076 DOI: 10.1016/j.devcel.2021.12.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 12/09/2021] [Accepted: 12/17/2021] [Indexed: 11/25/2022]
Abstract
The endoplasmic reticulum (ER)-to-Golgi transport is critical to protein secretion and intracellular sorting. Here, we report a highly elongated tubular ER-Golgi intermediate compartment (t-ERGIC) that selectively expedites the ER-to-Golgi transport for soluble cargoes of the receptor SURF4. Lacking the canonical ERGIC marker ERGIC-53 yet positive for the small GTPases Rab1A/B, the t-ERGIC is further marked by its extraordinarily elongated and thinned shape. With its large surface-to-volume ratio, high intracellular traveling speeds, and ER-Golgi recycling capabilities, the t-ERGIC accelerates the trafficking of SURF4-bound cargoes. The biogenesis and cargo selectivity of t-ERGIC both depend on SURF4, which recognizes the N terminus of soluble cargoes and co-clusters with the selected cargoes to expand the ER-exit site. In the steady state, the t-ERGIC-mediated fast ER-to-Golgi transport is antagonized by the KDEL-mediated ER retrieval. Together, our results argue that specific cargo-receptor interactions give rise to distinct transport carriers that regulate the trafficking kinetics.
Collapse
Affiliation(s)
- Rui Yan
- Department of Chemistry & California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA.
| | - Kun Chen
- Department of Chemistry & California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA, USA, 94720,Chan Zuckerberg Biohub, San Francisco, CA, USA, 94158
| | - Bowen Wang
- Department of Chemistry & California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA, USA, 94720,Chan Zuckerberg Biohub, San Francisco, CA, USA, 94158
| | - Ke Xu
- Department of Chemistry & California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA.
| |
Collapse
|
4
|
Jia W, Zhang R, Zhu Z, Shi L. A High-Throughput Comparative Proteomics of Milk Fat Globule Membrane Reveals Breed and Lactation Stages Specific Variation in Protein Abundance and Functional Differences Between Milk of Saanen Dairy Goat and Holstein Bovine. Front Nutr 2021; 8:680683. [PMID: 34124126 PMCID: PMC8193056 DOI: 10.3389/fnut.2021.680683] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 05/06/2021] [Indexed: 12/20/2022] Open
Abstract
Large variations in the bioactivities and composition of milk fat globule membrane (MFGM) proteins were observed between Saanen dairy goat and Holstein bovine at various lactation periods. In the present study, 331, 250, 182, and 248 MFGM proteins were characterized in colostrum and mature milk for the two species by Q-Orbitrap HRMS-based proteomics techniques. KEGG pathway analyses displayed that differentially expressed proteins in colostrum involved in galactose metabolism and an adipogenesis pathway, and the differentially expressed proteins in mature milk associated with lipid metabolism and a PPAR signaling pathway. These results indicated that the types and functions of MFGM proteins in goat and bovine milk were different, and goat milk had a better function of fatty acid metabolism and glucose homeostasis, which can enhance our understanding of MFGM proteins in these two species across different lactation periods, and they provide significant information for the study of lipid metabolism and glycometabolism of goat milk.
Collapse
Affiliation(s)
- Wei Jia
- School of Food and Biological Engineering, Shaanxi University of Science & Technology, Xi'an, China
| | - Rong Zhang
- School of Food and Biological Engineering, Shaanxi University of Science & Technology, Xi'an, China
| | - Zhenbao Zhu
- School of Food and Biological Engineering, Shaanxi University of Science & Technology, Xi'an, China
| | - Lin Shi
- School of Food and Biological Engineering, Shaanxi University of Science & Technology, Xi'an, China
| |
Collapse
|
5
|
Okamoto Y, Saito T, Tani Y, Toki T, Hasebe A, Koido M, Tomida A. The kinase PERK represses translation of the G-protein-coupled receptor LGR5 and receptor tyrosine kinase ERBB3 during ER stress in cancer cells. J Biol Chem 2020; 295:4591-4603. [PMID: 32107308 DOI: 10.1074/jbc.ra119.010655] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 02/21/2020] [Indexed: 01/10/2023] Open
Abstract
As a branch of the unfolded protein response, protein kinase R-like endoplasmic reticulum kinase (PERK) represses global translation in response to endoplasmic reticulum (ER) stress. This pathophysiological condition is associated with the tumor microenvironment in cancer. Previous findings in our lab have suggested that PERK selectively represses translation of some mRNAs, but this possibility awaits additional investigation. In this study, we show that a stem-cell marker protein, leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5), is rapidly depleted in colon cancer cells during ER stress, an effect that depended on the PERK-mediated translational repression. Indeed, the PERK inhibition led to the accumulation of premature, underglycosylated forms of LGR5, which were produced only at low levels during proper PERK activation. Unlike the mature LGR5 form, which is constitutively degraded regardless of PERK activation, the underglycosylated LGR5 exhibited a prolonged half-life and accumulated inside the cells without being expressed on the cell surface. We also found that Erb-B2 receptor tyrosine kinase 3 (ERBB3) is subjected to a similarly-regulated depletion by PERK, whereas the epidermal growth factor receptor (EGFR), stress-inducible heat-shock protein family A (Hsp70) member 5 (HSPA5), and anterior gradient 2 protein-disulfide isomerase family member (AGR2) were relatively. insensitive to the PERK-mediated repression of translation. These results indicate that LGR5 and ERBB3 are targets for PERK-mediated translational repression during ER stress.
Collapse
Affiliation(s)
- Yuka Okamoto
- Genome Research, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo 135-8550, Japan
| | - Takuya Saito
- Genome Research, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo 135-8550, Japan
| | - Yuri Tani
- Genome Research, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo 135-8550, Japan
| | - Tamami Toki
- Genome Research, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo 135-8550, Japan
| | - Akiko Hasebe
- Genome Research, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo 135-8550, Japan
| | - Masaru Koido
- Genome Research, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo 135-8550, Japan
| | - Akihiro Tomida
- Genome Research, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo 135-8550, Japan
| |
Collapse
|
6
|
Balasubramanian V, Srinivasan B. Genetic analyses uncover pleiotropic compensatory roles for Drosophila Nucleobindin-1 in inositol trisphosphate-mediated intracellular calcium homeostasis. Genome 2019; 63:61-90. [PMID: 31557446 DOI: 10.1139/gen-2019-0113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nucleobindin-1 is an EF-hand calcium-binding protein with a distinctive profile, predominantly localized to the Golgi in insect and wide-ranging vertebrate cell types, alike. Its putative involvements in intracellular calcium (Ca2+) homeostasis have never been phenotypically characterized in any model organism. We have analyzed an adult-viable mutant that completely disrupts the G protein α-subunit binding and activating (GBA) motif of Drosophila Nucleobindin-1 (dmNUCB1). Such disruption does not manifest any obvious fitness-related, morphological/developmental, or behavioral abnormalities. A single copy of this mutation or the knockdown of dmnucb1 in restricted sets of cells variously rescues pleiotropic mutant phenotypes arising from impaired inositol 1,4,5-trisphosphate receptor (IP3R) activity (in turn depleting cytoplasmic Ca2+ levels across diverse tissue types). Additionally, altered dmNUCB1 expression or function considerably reverses lifespan and mobility improvements effected by IP3R mutants, in a Drosophila model of amyotrophic lateral sclerosis. Homology modeling-based analyses further predict a high degree of conformational conservation in Drosophila, of biochemically validated structural determinants in the GBA motif that specify in vertebrates, the unconventional Ca2+-regulated interaction of NUCB1 with Gαi subunits. The broad implications of our findings are hypothetically discussed, regarding potential roles for NUCB1 in GBA-mediated, Golgi-associated Ca2+ signaling, in health and disease.
Collapse
Affiliation(s)
- Vidhya Balasubramanian
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology-Madras, Chennai 600036, India.,Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology-Madras, Chennai 600036, India
| | - Bharath Srinivasan
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology-Madras, Chennai 600036, India.,Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology-Madras, Chennai 600036, India
| |
Collapse
|
7
|
Leung AKW, Ramesh N, Vogel C, Unniappan S. Nucleobindins and encoded peptides: From cell signaling to physiology. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2019; 116:91-133. [PMID: 31036300 DOI: 10.1016/bs.apcsb.2019.02.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Nucleobindins (NUCBs) are DNA and calcium binding, secreted proteins with various signaling functions. Two NUCBs, nucleobindin-1 (NUCB1) and nucleobindin-2 (NUCB2), were discovered during the 1990s. These two peptides are shown to have diverse functions, including the regulation of inflammation and bone formation, among others. In 2006, Oh-I and colleagues discovered that three peptides encoded within the NUCB2 could be processed by prohormone convertases. These peptides were named nesfatin-1, 2 and 3, mainly due to the satiety and fat influencing properties of nesfatin-1. However, it was found that nesfatin-2 and -3 have no such effects. Nesfatin-1, especially its mid-segment, is very highly conserved across vertebrates. Although the receptor(s) that mediate nesfatin-1 effects are currently unknown, it is now considered an endogenous peptide with multiple functions, affecting central and peripheral tissues to regulate metabolism, reproduction, endocrine and other functions. We recently identified a nesfatin-1-like peptide (NLP) encoded within the NUCB1. Like nesfatin-1, NLP suppressed feed intake in mice and fish, and stimulated insulin secretion from pancreatic beta cells. There is considerable evidence available to indicate that nucleobindins and its encoded peptides are multifunctional regulators of cell biology and whole animal physiology. This review aims to briefly discuss the structure, distribution, functions and mechanism of action nucleobindins and encoded peptides.
Collapse
Affiliation(s)
- Adelaine Kwun-Wai Leung
- Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, Saskatoon, SK, Canada
| | - Naresh Ramesh
- Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, Saskatoon, SK, Canada
| | - Christine Vogel
- Department of Biology, New York University, New York, NY, United States
| | - Suraj Unniappan
- Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, Saskatoon, SK, Canada.
| |
Collapse
|
8
|
Yin Y, Garcia MR, Novak AJ, Saunders AM, Ank RS, Nam AS, Fisher LW. Surf4 (Erv29p) binds amino-terminal tripeptide motifs of soluble cargo proteins with different affinities, enabling prioritization of their exit from the endoplasmic reticulum. PLoS Biol 2018; 16:e2005140. [PMID: 30086131 PMCID: PMC6097701 DOI: 10.1371/journal.pbio.2005140] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 08/17/2018] [Accepted: 07/17/2018] [Indexed: 01/16/2023] Open
Abstract
Some secreted proteins that assemble into large complexes, such as extracellular matrices or hormones and enzymes in storage granules, must be kept at subaggregation concentrations during intracellular trafficking. We show surfeit locus protein 4 (Surf4) is the cargo receptor that establishes different steady-state concentrations for a variety of soluble cargo proteins within the endoplasmic reticulum (ER) through interaction with the amino-terminal tripeptides exposed after removal of leader sequences. We call this motif the ER-Exit by Soluble Cargo using Amino-terminal Peptide-Encoding motif (ER-ESCAPE motif). Proteins that most readily aggregate in the ER lumen (e.g., dentin sialophosphoprotein [DSPP] and amelogenin, X-linked [AMELX]) have strong ER-ESCAPE motifs to inhibit aggregate formation, while less susceptible cargo exhibits weaker motifs. Specific changes in a single amino acid of the tripeptide result in aggregate formation and failure to efficiently traffic cargo out of the ER. A logical subset of 8,000 possible tripeptides starting a model soluble cargo protein (growth hormone) established a continuum of steady-state ER concentrations ranging from low (i.e., high affinity for receptor) to the highest concentrations associated with bulk flow-limited trafficking observed for nonbinding motifs. Human cells lacking Surf4 no longer preferentially trafficked cargo expressing strong ER-ESCAPE motifs. Reexpression of Surf4 or expression of yeast's ortholog, ER-derived vesicles protein 29 (Erv29p), rescued enhanced ER trafficking in Surf4-null cells. Hence our work describes a new way of preferentially exporting soluble cargo out of the ER that maintains proteins below the concentrations at which they form damaging aggregates.
Collapse
Affiliation(s)
- Ying Yin
- Matrix Biochemistry Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Mekka R. Garcia
- Matrix Biochemistry Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Alexander J. Novak
- Matrix Biochemistry Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Allison M. Saunders
- Matrix Biochemistry Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Raira S. Ank
- Matrix Biochemistry Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Anna S. Nam
- Matrix Biochemistry Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Larry W. Fisher
- Matrix Biochemistry Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, United States of America
| |
Collapse
|
9
|
Gawli K, Ramesh N, Unniappan S. Nesfatin-1-like peptide is a novel metabolic factor that suppresses feeding, and regulates whole-body energy homeostasis in male Wistar rats. PLoS One 2017; 12:e0178329. [PMID: 28542568 PMCID: PMC5444818 DOI: 10.1371/journal.pone.0178329] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Accepted: 05/11/2017] [Indexed: 12/26/2022] Open
Abstract
Nucleobindin-1 has high sequence similarity to nucleobindin-2, which encodes the anorectic and metabolic peptide, nesfatin-1. We previously reported a nesfatin-1-like peptide (NLP), anorectic in fish and insulinotropic in mice islet beta-like cells. The main objective of this research was to determine whether NLP is a metabolic regulator in male Wistar rats. A single intraperitoneal (IP) injection of NLP (100 μg/kg BW) decreased food intake and increased ambulatory movement, without causing any change in total activity or energy expenditure when compared to saline-treated rats. Continuous subcutaneous infusion of NLP (100 μg/kg BW) using osmotic mini-pumps for 7 days caused a reduction in food intake on days 3 and 4. Similarly, water intake was also reduced for two days (days 3 and 4) with the effect being observed during the dark phase. This was accompanied by an increased RER and energy expenditure. However, decreased whole-body fat oxidation, and total activity were observed during the long-term treatment (7 days). Body weight gain was not significantly different between control and NLP infused rats. The expression of mRNAs encoding adiponectin, resistin, ghrelin, cholecystokinin and uncoupling protein 1 (UCP1) were significantly upregulated, while leptin and peptide YY mRNA expression was downregulated in NLP-treated rats. These findings indicate that administration of NLP at 100 μg/kg BW reduces food intake and modulates whole body energy balance. In summary, NLP is a novel metabolic peptide in rats.
Collapse
Affiliation(s)
- Kavishankar Gawli
- Laboratory of Integrative Neuroendocrinology, Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada
| | - Naresh Ramesh
- Laboratory of Integrative Neuroendocrinology, Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada
| | - Suraj Unniappan
- Laboratory of Integrative Neuroendocrinology, Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada
- * E-mail:
| |
Collapse
|
10
|
Blank B, von Blume J. Cab45-Unraveling key features of a novel secretory cargo sorter at the trans-Golgi network. Eur J Cell Biol 2017; 96:383-390. [PMID: 28372832 DOI: 10.1016/j.ejcb.2017.03.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 02/27/2017] [Accepted: 03/02/2017] [Indexed: 12/15/2022] Open
Abstract
The accurate and efficient delivery of proteins to specific domains of the plasma membrane or to the extracellular space is critical for the ordered function of surface receptors and proteins such as insulin, collagens, antibodies, extracellular proteases. The trans-Golgi network is responsible for sorting proteins onto specific carriers for transport to their final destination. The role of the mannose-6-phosphate receptor in the sorting of hydrolases destined for lysosomes has been studied extensively, but the sorting mechanisms for secreted proteins remains poorly understood. We recently described a novel process that links the cytoplasmic actin cytoskeleton to the membrane-anchored Ca2+ ATPase SPCA1 and the lumenal Ca2+-binding protein Cab45, which mediates sorting of a subset of secretory proteins at the TGN. In response to Ca2+ influx, Cab45 forms oligomers, enabling it to bind a variety of specific cargo molecules. Thus, we suggest that this represents a novel way to export cargo molecules without the need for a bona fide transmembrane cargo receptor. This review focuses on Cab45's molecular function and highlights its possible role in disease.
Collapse
Affiliation(s)
- Birgit Blank
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Julia von Blume
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
| |
Collapse
|
11
|
Wu FL, Liu WY, Van Poucke S, Braddock M, Jin WM, Xiao J, Li XK, Zheng MH. Targeting endoplasmic reticulum stress in liver disease. Expert Rev Gastroenterol Hepatol 2016; 10:1041-52. [PMID: 27093595 DOI: 10.1080/17474124.2016.1179575] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
INTRODUCTION The accumulation of unfolded protein in the endoplasmic reticulum (ER) initiates an unfolded protein response (UPR) via three signal transduction cascades, which involve protein kinase RNA-like ER kinase (PERK), inositol requiring enzyme-1α (IRE1α) and activating transcription factor-6α (ATF6α). An ER stress response is observed in nearly all physiologies related to acute and chronic liver disease and therapeutic targeting of the mechanisms implicated in UPR signaling have attracted considerable attention. AREAS COVERED This review focuses on the correlation between ER stress and liver disease and the possible targets which may drive the potential for novel therapeutic intervention. Expert Commentary: We describe pathways which are involved in UPR signaling and their potential correlation with various liver diseases and underlying mechanisms which may present opportunities for novel therapeutic strategies are discussed.
Collapse
Affiliation(s)
- Fa-Ling Wu
- a Department of Hepatology, Liver Research Center , the First Affiliated Hospital of Wenzhou Medical University , Wenzhou , China.,b Institute of Hepatology , Wenzhou Medical University , Wenzhou , China
| | - Wen-Yue Liu
- c Department of Endocrinology , the First Affiliated Hospital of Wenzhou Medical University , Wenzhou , China
| | - Sven Van Poucke
- d Department of Anesthesiology, Intensive Care, Emergency Medicine and Pain Therapy , Ziekenhuis Oost-Limburg , Genk , Belgium
| | - Martin Braddock
- e Global Medicines Development , AstraZeneca R&D , Alderley Park , UK
| | - Wei-Min Jin
- f Department of Infection Diseases , People Hospital of Wencheng County , Wenzhou , China
| | - Jian Xiao
- g Institute of Biology Science , Wenzhou University , Wenzhou , China.,h School of Pharmacy , Wenzhou Medical University , Wenzhou , China
| | - Xiao-Kun Li
- g Institute of Biology Science , Wenzhou University , Wenzhou , China.,h School of Pharmacy , Wenzhou Medical University , Wenzhou , China
| | - Ming-Hua Zheng
- a Department of Hepatology, Liver Research Center , the First Affiliated Hospital of Wenzhou Medical University , Wenzhou , China.,b Institute of Hepatology , Wenzhou Medical University , Wenzhou , China
| |
Collapse
|
12
|
Liang T, Meng T, Wang S, Qin C, Lu Y. The LPV Motif Is Essential for the Efficient Export of Secretory DMP1 From the Endoplasmic Reticulum. J Cell Physiol 2015; 231:1468-75. [PMID: 26595451 DOI: 10.1002/jcp.25265] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2015] [Accepted: 11/19/2015] [Indexed: 11/07/2022]
Abstract
Dentin matrix protein 1 (DMP1) is found abundantly in the extracellular matrices of bone and dentin. Secretory DMP1 begins with a tripeptide of leucine-proline-valine (LPV) after the endoplasmic reticulum (ER)-entry signal peptide is cleaved. The goal of this study was to determine the role of the LPV motif in the secretion of DMP1. A series of DNA constructs was generated to express various forms of DMP1 with or without the LPV motif. These constructs were transfected into a preosteoblast cell line, the MC3T3-E1 cells, and the subcellular localization and secretion of various forms of DMP1 were examined by immunofluorescent staining and Western-blotting analyses. Immunofluorescent staining showed that the LPV-containing DMP1 variants were primarily localized in the Golgi complex, whereas the LPV-lacking DMP1 variants were found abundantly within the ER. Western-blotting analyses demonstrated that the LPV-containing DMP1 variants were rapidly secreted from the transfected cells, as they did not accumulate within the cells, and the amounts increased in the conditioned media over time. In contrast, the LPV-lacking DMP1 variants were predominantly retained within the cells, and only small amounts were secreted out of the cells over time. These results suggest that the LPV motif is essential for the efficient export of secretory DMP1 from the ER to the Golgi complex.
Collapse
Affiliation(s)
- Tian Liang
- Department of Biomedical Sciences and Center for Craniofacial Research and Diagnosis, Texas A&M University Baylor College of Dentistry, Dallas, Texas
| | - Tian Meng
- Department of Biomedical Sciences and Center for Craniofacial Research and Diagnosis, Texas A&M University Baylor College of Dentistry, Dallas, Texas
| | - Suzhen Wang
- Department of Biomedical Sciences and Center for Craniofacial Research and Diagnosis, Texas A&M University Baylor College of Dentistry, Dallas, Texas
| | - Chunlin Qin
- Department of Biomedical Sciences and Center for Craniofacial Research and Diagnosis, Texas A&M University Baylor College of Dentistry, Dallas, Texas
| | - Yongbo Lu
- Department of Biomedical Sciences and Center for Craniofacial Research and Diagnosis, Texas A&M University Baylor College of Dentistry, Dallas, Texas
| |
Collapse
|
13
|
Zhang H, Maqsudi S, Rainczuk A, Duffield N, Lawrence J, Keane FM, Justa-Schuch D, Geiss-Friedlander R, Gorrell MD, Stephens AN. Identification of novel dipeptidyl peptidase 9 substrates by two-dimensional differential in-gel electrophoresis. FEBS J 2015; 282:3737-57. [PMID: 26175140 DOI: 10.1111/febs.13371] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 06/22/2015] [Accepted: 07/07/2015] [Indexed: 12/26/2022]
Abstract
Dipeptidyl peptidase 9 (DPP9) is a member of the S9B/DPPIV (DPP4) serine protease family, which cleaves N-terminal dipeptides at an Xaa-Pro consensus motif. Cytoplasmic DPP9 has roles in epidermal growth factor signalling and in antigen processing, whilst the role of the recently discovered nuclear form of DPP9 is unknown. Mice lacking DPP9 proteolytic activity die as neonates. We applied a modified 2D differential in-gel electrophoresis approach to identify novel DPP9 substrates, using mouse embryonic fibroblasts lacking endogenous DPP9 activity. A total of 111 potential new DPP9 substrates were identified, with nine proteins/peptides confirmed as DPP9 substrates by MALDI-TOF or immunoblotting. Moreover, we also identified the dipeptide Val-Ala as a consensus site for DPP9 cleavage that was not recognized by DPP8, suggesting different in vivo roles for these closely related enzymes. The relative kinetics for the cleavage of these nine candidate substrates by DPP9, DPP8 and DPP4 were determined. This is the first identification of DPP9 substrates from cells lacking endogenous DPP9 activity. These data greatly expand the potential roles of DPP9 and suggest different in vivo roles for DPP9 and DPP8.
Collapse
Affiliation(s)
- Hui Zhang
- Molecular Hepatology, Liver Injury and Cancer Group, Centenary Institute, Sydney Medical School, University of Sydney, Australia
| | - Sadiqa Maqsudi
- Centre for Cancer Research, Hudson Institute of Medical Research, Clayton, Australia.,Department of Molecular and Translational Sciences, Monash University, Clayton, Australia
| | - Adam Rainczuk
- Centre for Cancer Research, Hudson Institute of Medical Research, Clayton, Australia.,Department of Molecular and Translational Sciences, Monash University, Clayton, Australia
| | - Nadine Duffield
- Centre for Cancer Research, Hudson Institute of Medical Research, Clayton, Australia.,Department of Molecular and Translational Sciences, Monash University, Clayton, Australia
| | - Josie Lawrence
- Centre for Cancer Research, Hudson Institute of Medical Research, Clayton, Australia.,Department of Molecular and Translational Sciences, Monash University, Clayton, Australia
| | - Fiona M Keane
- Molecular Hepatology, Liver Injury and Cancer Group, Centenary Institute, Sydney Medical School, University of Sydney, Australia
| | - Daniela Justa-Schuch
- Department of Molecular Biology, Faculty of Medicine, Georg-August-University of Goettingen, Germany
| | - Ruth Geiss-Friedlander
- Department of Molecular Biology, Faculty of Medicine, Georg-August-University of Goettingen, Germany
| | - Mark D Gorrell
- Molecular Hepatology, Liver Injury and Cancer Group, Centenary Institute, Sydney Medical School, University of Sydney, Australia
| | - Andrew N Stephens
- Centre for Cancer Research, Hudson Institute of Medical Research, Clayton, Australia.,Department of Molecular and Translational Sciences, Monash University, Clayton, Australia.,Epworth Research Institute, Epworth HealthCare, Richmond, Victoria, Australia
| |
Collapse
|
14
|
Abascal F, Tress ML, Valencia A. The evolutionary fate of alternatively spliced homologous exons after gene duplication. Genome Biol Evol 2015; 7:1392-403. [PMID: 25931610 PMCID: PMC4494069 DOI: 10.1093/gbe/evv076] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Alternative splicing and gene duplication are the two main processes responsible for expanding protein functional diversity. Although gene duplication can generate new genes and alternative splicing can introduce variation through alternative gene products, the interplay between the two processes is complex and poorly understood. Here, we have carried out a study of the evolution of alternatively spliced exons after gene duplication to better understand the interaction between the two processes. We created a manually curated set of 97 human genes with mutually exclusively spliced homologous exons and analyzed the evolution of these exons across five distantly related vertebrates (lamprey, spotted gar, zebrafish, fugu, and coelacanth). Most of these exons had an ancient origin (more than 400 Ma). We found examples supporting two extreme evolutionary models for the behaviour of homologous axons after gene duplication. We observed 11 events in which gene duplication was accompanied by splice isoform separation, that is, each paralog specifically conserved just one distinct ancestral homologous exon. At other extreme, we identified genes in which the homologous exons were always conserved within paralogs, suggesting that the alternative splicing event cannot easily be separated from the function in these genes. That many homologous exons fall in between these two extremes highlights the diversity of biological systems and suggests that the subtle balance between alternative splicing and gene duplication is adjusted to the specific cellular context of each gene.
Collapse
Affiliation(s)
- Federico Abascal
- Structural Biology and Biocomputing Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Michael L Tress
- Structural Biology and Biocomputing Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Alfonso Valencia
- Structural Biology and Biocomputing Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| |
Collapse
|
15
|
Calcium-Sensing Receptor. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 132:127-50. [DOI: 10.1016/bs.pmbts.2015.02.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
16
|
Serra-Soriano M, Pallás V, Navarro JA. A model for transport of a viral membrane protein through the early secretory pathway: minimal sequence and endoplasmic reticulum lateral mobility requirements. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 77:863-79. [PMID: 24438546 DOI: 10.1111/tpj.12435] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 12/30/2013] [Accepted: 01/09/2014] [Indexed: 05/19/2023]
Abstract
Viral movement proteins exploit host endomembranes and the cytoskeleton to move within the cell via routes that, in some cases, are dependent on the secretory pathway. For example, melon necrotic spot virus p7B, a type II transmembrane protein, leaves the endoplasmic reticulum (ER) through the COPII-dependent Golgi pathway to reach the plasmodesmata. Here we investigated the sequence requirements and putative mechanisms governing p7B transport through the early secretory pathway. Deletion of either the cytoplasmic N-terminal region (CR) or the luminal C-terminal region (LR) led to ER retention, suggesting that they are both essential for ER export. Through alanine-scanning mutagenesis, we identified residues in the CR and LR that are critical for both ER export and for viral cell-to-cell movement. Within the CR, alanine substitution of aspartic and proline residues in the DSSP β-turn motif (D7 AP10 A) led to movement of discrete structures along the cortical ER in an actin-dependent manner. In contrast, alanine substitution of a lysine residue in the LR (K49 A) resulted in a homogenous ER distribution of the movement protein and inhibition of ER-Golgi traffic. Moreover, the ability of p7B to recruit Sar1 to the ER membrane is lost in the D7 AP10 A mutant, but enhanced in the K49 A mutant. In addition, fluorescence recovery after photobleaching revealed that K49 A but not D7 AP10 A dramatically diminished protein lateral mobility. From these data, we propose a model whereby the LR directs actin-dependent mobility toward the cortical ER, where the cytoplasmic DSSP β-turn favors assembly of COPII vesicles for export of p7B from the ER.
Collapse
Affiliation(s)
- Marta Serra-Soriano
- Instituto de Biología Molecular y Celular de Plantas, Universitat Politècnica de València/Consejo Superior de Investigaciones Científicas, Avenida Ingeniero Fausto Elio s/n, 46022, Valencia, Spain
| | | | | |
Collapse
|
17
|
Kramann N, Hasenfuß G, Seidler T. B-RAF and its novel negative regulator reticulocalbin 1 (RCN1) modulates cardiomyocyte hypertrophy. Cardiovasc Res 2014; 102:88-96. [PMID: 24492844 DOI: 10.1093/cvr/cvu024] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIM Activation of the kinase RAF and its downstream targets leads to cardiomyocyte hypertrophy. It has been hypothesized that B-RAF might be the main activator of MEK in various cell types. Therefore, the aim of this study was to investigate the role of B-RAF and its modulating factors in cardiomyocyte hypertrophy. METHODS AND RESULTS Neonatal rat cardiomyocytes were pre-treated with and without the specific B-RAF inhibitor SB590885 and then stimulated with phenylephrine to induce hypertrophy. Inhibition of B-RAF completely impeded the hypertrophic response and led to a significant reduction of MEK1/2 phosphorylation. By applying a eukaryotic cDNA expression screen, based on a dual-luciferase reporter assay for B-RAF activity measurement, we identified RCN1 as a new negative modulator of B-RAF activity. Adenovirus-mediated overexpression of reticulocalbin 1 (RCN1) completely impeded phenylephrine-induced hypertrophy and led to significantly reduced MEK1/2 phosphorylation. Conversely, adenoviral knockdown of RCN1 with a specific synthetic miRNA induced cardiomyocyte hypertrophy and significantly increased MEK1/2 phosphorylation. CONCLUSIONS In summary, our results show that the inhibition of B-RAF abolishes cardiomyocyte hypertrophy and we identified RCN1 as novel negative modulator of cardiomyocyte hypertrophy by inhibition of the mitogen-activated protein kinase signalling cascade. Our results show that B-RAF kinase activity is essential for cardiac hypertrophy and RCN1, its newly identified negative regulator, abolishes hypertrophic response of cardiomyocytes in vitro.
Collapse
Affiliation(s)
- Nadine Kramann
- Department of Cardiology and Pulmonology, University Medical Centre Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
| | | | | |
Collapse
|
18
|
Suzuki N, Ban S, Itoh E, Chen S, Imai FL, Sawano Y, Miyakawa T, Tanokura M, Yonezawa N. Calcium-dependent structural changes in human reticulocalbin-1. J Biochem 2014; 155:281-93. [PMID: 24451493 DOI: 10.1093/jb/mvu003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Human reticulocalbin-1 (hRCN1) has six EF-hand motifs and binds Ca(2+). hRCN1 is a member of the CREC family localized in the secretory pathway, and its cellular function remains unclear. In this study, we established a new bacterial expression and purification procedure for hRCN1. We observed that hRCN1 binds Ca(2+) in a cooperative manner and the Ca(2+) binding caused an increase in the α-helix content of hRCN1. On the other hand, hRCN1 did not change the structure with Mg(2+) loading. hRCN1 is a monomeric protein, and its overall structure became more compact upon Ca(2+) binding, as revealed by gel-filtration column chromatography and small-angle X-ray scattering. This is the first report of conformational changes in the CREC family upon Ca(2+) binding. Our data suggest that CREC family member interactions with target proteins are regulated in the secretory pathway by conformational changes upon Ca(2+) binding.
Collapse
Affiliation(s)
- Nanao Suzuki
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba 263-8522, Japan; Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo 113-8657, Japan; and Laboratory of Chemistry, College of Liberal and Sciences, Tokyo Medical and Dental University, Chiba 272-0827, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Feng H, Chen L, Wang Q, Shen B, Liu L, Zheng P, Xu S, Liu X, Chen J, Teng J. Calumenin-15 facilitates filopodia formation by promoting TGF-β superfamily cytokine GDF-15 transcription. Cell Death Dis 2013; 4:e870. [PMID: 24136234 PMCID: PMC3920949 DOI: 10.1038/cddis.2013.403] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 09/04/2013] [Accepted: 09/11/2013] [Indexed: 12/12/2022]
Abstract
Filopodia, which are actin-rich finger-like membrane protrusions, have an important role in cell migration and tumor metastasis. Here we identify 13 novel calumenin (Calu) isoforms (Calu 3-15) produced by alternative splicing, and find that Calu-15 promotes filopodia formation and cell migration. Calu-15 shuttles between the nucleus and cytoplasm through interacting with importin α, Ran GTPase, and Crm1. The phosphorylation of the threonine at position 73 (Thr-73) by casein kinase 2 (CK2) is essential for the nuclear import of Calu-15, and either Thr-73 mutation or inhibition of CK2 interrupts its nuclear localization. In the nucleus, Calu-15 increases the transcription of growth differentiation factor-15 (GDF-15), a member of the transforming growth factor-β (TGF-β) superfamily, via binding to its promoter region. Furthermore, Calu-15 induces filopodia formation mediated by GDF-15. Together, we identify that Calu-15, a novel isoform of Calu with phosphorylation-dependent nuclear localization, has a critical role in promoting filopodia formation and cell migration by upregulating the GDF-15 transcription.
Collapse
Affiliation(s)
- H Feng
- State Key Laboratory of Bio-membrane and Membrane Bio-engineering, Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, China
| | - L Chen
- State Key Laboratory of Bio-membrane and Membrane Bio-engineering, Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, China
| | - Q Wang
- State Key Laboratory of Bio-membrane and Membrane Bio-engineering, Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, China
| | - B Shen
- State Key Laboratory of Bio-membrane and Membrane Bio-engineering, Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, China
| | - L Liu
- State Key Laboratory of Bio-membrane and Membrane Bio-engineering, Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, China
| | - P Zheng
- State Key Laboratory of Bio-membrane and Membrane Bio-engineering, Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, China
| | - S Xu
- State Key Laboratory of Bio-membrane and Membrane Bio-engineering, Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, China
| | - X Liu
- State Key Laboratory of Bio-membrane and Membrane Bio-engineering, Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, China
| | - J Chen
- State Key Laboratory of Bio-membrane and Membrane Bio-engineering, Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, China
- Center for Quantitative Biology, Peking University, Beijing, China
| | - J Teng
- State Key Laboratory of Bio-membrane and Membrane Bio-engineering, Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, China
| |
Collapse
|
20
|
A DSPP mutation causing dentinogenesis imperfecta and characterization of the mutational effect. BIOMED RESEARCH INTERNATIONAL 2012; 2013:948181. [PMID: 23509818 PMCID: PMC3591212 DOI: 10.1155/2013/948181] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Revised: 09/28/2012] [Accepted: 10/12/2012] [Indexed: 11/17/2022]
Abstract
Mutations in the DSPP gene have been identified in nonsyndromic hereditary dentin defects, but the genotype-phenotype correlations are not fully understood. Recently, it has been demonstrated that the mutations of DSPP affecting the IPV leader sequence result in mutant DSPP retention in rough endoplasmic reticulum (ER). In this study, we identified a Korean family with dentinogenesis imperfecta type III. To identify the disease causing mutation in this family, we performed mutational analysis based on candidate gene sequencing. Exons and exon-intron boundaries of DSPP gene were sequenced, and the effects of the identified mutation on the pre-mRNA splicing and protein secretion were investigated. Candidate gene sequencing revealed a mutation (c.50C > T, p.P17L) in exon 2 of the DSPP gene. The splicing assay showed that the mutation did not influence pre-mRNA splicing. However, the mutation interfered with protein secretion and resulted in the mutant protein remaining largely in the ER. These results suggest that the mutation affects ER-to-Golgi apparatus export and results in the reduction of secreted DSPP and ER overload. This may induce cell stress and damage processing and/or transport of dentin matrix proteins or other critical proteins.
Collapse
|
21
|
Gonzalez R, Mohan H, Unniappan S. Nucleobindins: bioactive precursor proteins encoding putative endocrine factors? Gen Comp Endocrinol 2012; 176:341-6. [PMID: 22154814 DOI: 10.1016/j.ygcen.2011.11.021] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2011] [Revised: 11/13/2011] [Accepted: 11/15/2011] [Indexed: 11/20/2022]
Abstract
The nucleobindins, nucleobindin 1 (NUCB1) and nucleobindin 2 (NUCB2), are homologous multidomain calcium and DNA binding proteins. NUCB1 is a well-characterized Golgi protein found within the rat pituitary, liver and kidney with functions related to immunity, calcium homeostasis and G protein signaling. NUCB2 is found both in the hypothalamus and brain stem centers, as well as peripherally in the digestive tract. Renewed interest in the nucleobindins has been sparked by the recent discovery of nesfatin-1, an endocrine factor post-translationally processed from the N-terminal of NUCB2. Nesfatin-1 has quickly established itself as a novel regulator of appetite, insulin secretion, energy homeostasis and reproduction with important consequences to the etiology of metabolic diseases including diabetes and obesity. The discovery of nesfatin-1 and it endocrine functions attracted more attention to the nucleobindins that are already known to have important intracellular functions. From the sequence information available, it is possible that nucelobindins itself or nesfatin-1 like peptides within the NUCB1 could also elicit nesfatin-1-like biological functions. The research on nesfatin-1 in last 5years further adds to the importance of nucleobindins as potential endocrine precursors. This review aims to summarize some of the most recent findings on the functional significance of NUCB1, NUCB2, as well as encoded proteins and highlights the questions that remain unanswered.
Collapse
Affiliation(s)
- Ronald Gonzalez
- Laboratory of Integrative Neuroendocrinology, Department of Biology, York University, Toronto, Ontario, Canada
| | | | | |
Collapse
|
22
|
Wang Q, Feng H, Zheng P, Shen B, Chen L, Liu L, Liu X, Hao Q, Wang S, Chen J, Teng J. The intracellular transport and secretion of calumenin-1/2 in living cells. PLoS One 2012; 7:e35344. [PMID: 22514732 PMCID: PMC3325945 DOI: 10.1371/journal.pone.0035344] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 03/14/2012] [Indexed: 01/05/2023] Open
Abstract
Calumenin isoforms 1 and 2 (calu-1/2), encoded by the CALU gene, belong to the CREC protein family. Calu-1/2 proteins are secreted into the extracellular space, but the secretory process and regulatory mechanism are largely unknown. Here, using a time-lapse imaging system, we visualized the intracellular transport and secretory process of calu-1/2-EGFP after their translocation into the ER lumen. Interestingly, we observed that an abundance of calu-1/2-EGFP accumulated in cellular processes before being released into the extracellular space, while only part of calu-1/2-EGFP proteins were secreted directly after attaching to the cell periphery. Moreover, we found the secretion of calu-1/2-EGFP required microtubule integrity, and that calu-1/2-EGFP-containing vesicles were transported by the motor proteins Kif5b and cytoplasmic dynein. Finally, we determined the export signal of calu-1/2-EGFP (amino acid positions 20–46) and provided evidence that the asparagine at site 131 was indispensable for calu-1/2-EGFP stabilization. Taken together, we provide a detailed picture of the intracellular transport of calu-1/2-EGFP, which facilitates our understanding of the secretory mechanism of calu-1/2.
Collapse
Affiliation(s)
- Qiao Wang
- State Key Laboratory of Bio-membrane and Membrane Bio-engineering and Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, China
| | - Hui Feng
- State Key Laboratory of Bio-membrane and Membrane Bio-engineering and Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, China
| | - Pengli Zheng
- State Key Laboratory of Bio-membrane and Membrane Bio-engineering and Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, China
| | - Birong Shen
- State Key Laboratory of Bio-membrane and Membrane Bio-engineering and Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, China
| | - Liang Chen
- State Key Laboratory of Bio-membrane and Membrane Bio-engineering and Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, China
| | - Lin Liu
- State Key Laboratory of Bio-membrane and Membrane Bio-engineering and Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, China
| | - Xiao Liu
- State Key Laboratory of Bio-membrane and Membrane Bio-engineering and Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, China
| | - Qingsong Hao
- State Key Laboratory of Bio-membrane and Membrane Bio-engineering and Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, China
| | - Shunchang Wang
- State Key Laboratory of Bio-membrane and Membrane Bio-engineering and Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, China
| | - Jianguo Chen
- State Key Laboratory of Bio-membrane and Membrane Bio-engineering and Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, China
- Center for Theoretical Biology, Peking University, Beijing, China
| | - Junlin Teng
- State Key Laboratory of Bio-membrane and Membrane Bio-engineering and Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, China
- * E-mail:
| |
Collapse
|
23
|
Wang SK, Chan HC, Rajderkar S, Milkovich RN, Uston KA, Kim JW, Simmer JP, Hu JCC. Enamel malformations associated with a defined dentin sialophosphoprotein mutation in two families. Eur J Oral Sci 2011; 119 Suppl 1:158-67. [PMID: 22243242 PMCID: PMC3266624 DOI: 10.1111/j.1600-0722.2011.00874.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Dentin sialophosphoprotein (DSPP) mutations cause dentin dysplasia type II (DD-II) and dentinogenesis imperfecta types II and III (DGI-II and DGI-III, respectively). We identified two kindreds with DGI-II who exhibited vertical bands of hypoplastic enamel. Both families had a previously reported DSPP mutation that segregated with the disease phenotype. Oral photographs and dental radiographs of four affected and one unaffected participant in one family and of the proband in the second family were used to document the dental phenotypes. We aligned the 33 unique allelic DSPP sequences showing variable patterns of insertions and deletions (indels), generated a merged dentin phosphoprotein (DPP) sequence that includes sequences from all DSPP length haplotypes, and mapped the known DSPP mutations in this context. Analyses of the DSPP sequence changes and their probable effects on protein expression, as well as published findings of the dental phenotype in Dspp null mice, support the hypothesis that all DSPP mutations cause pathology through dominant-negative effects. Noting that Dspp is transiently expressed by mouse pre-ameloblasts during formation of the dentino-enamel junction, we hypothesize that DSPP dominant-negative effects potentially cause cellular pathology in pre-ameloblasts that, in turn, causes enamel defects. We conclude that enamel defects can be part of the dental phenotype caused by DSPP mutations, although DSPP is not critical for dental enamel formation.
Collapse
Affiliation(s)
- Shih-Kai Wang
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, 1210 Eisenhower Place, Ann Arbor, MI, USA 48108
- Oral Health Sciences program, University of Michigan School of Dentistry; 1011 North University, Ann Arbor, MI, USA 48109
| | - Hui-Chen Chan
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, 1210 Eisenhower Place, Ann Arbor, MI, USA 48108
| | - Sudha Rajderkar
- Oral Health Sciences program, University of Michigan School of Dentistry; 1011 North University, Ann Arbor, MI, USA 48109
| | - Rachel N. Milkovich
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, 1210 Eisenhower Place, Ann Arbor, MI, USA 48108
| | - Karen A. Uston
- Department of Orthodontics and Pediatric Dentistry, University of Michigan School of Dentistry, 1011 North University, Ann Arbor, MI, USA 48109
| | - Jung-Wook Kim
- Department of Pediatric Dentistry & Dental Research Institute, School of Dentistry, Seoul National University, 275-1 Yongon-dong, Chongno-gu, Seoul 110-768, Korea
| | - James P. Simmer
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, 1210 Eisenhower Place, Ann Arbor, MI, USA 48108
| | - Jan C-C. Hu
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, 1210 Eisenhower Place, Ann Arbor, MI, USA 48108
| |
Collapse
|
24
|
Protein Quality Control, Retention, and Degradation at the Endoplasmic Reticulum. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2011; 292:197-280. [DOI: 10.1016/b978-0-12-386033-0.00005-0] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
25
|
Abstract
Since the proposal of the signal hypothesis on protein subcellular sorting, a number of computational analyses have been performed in this field. A typical example is the development of prediction algorithms for the subcellular localization sites of input protein sequences. In this review, we mainly focus on the biological grounds of the prediction methods rather than the algorithmic issues because we believe the former will be more fruitful for future development. Recent advances on the study of protein sorting signals will hopefully be incorporated into future prediction methods. Unfortunately, many of the state-of-the-art methods are published without sufficient objective tests. In fact, a simple test employed in this article shows that the performance of specifically developed predictors is not significantly better than that of a homology search. We suspect that this is a general problem associated with the interpretation of genome sequences, which have evolved through gene duplication and speciation.
Collapse
Affiliation(s)
- Kenichiro Imai
- Computational Biology Research Center, AIST, Tokyo, Japan
| | | |
Collapse
|
26
|
Kapoor N, Gupta R, Menon ST, Folta-Stogniew E, Raleigh DP, Sakmar TP. Nucleobindin 1 is a calcium-regulated guanine nucleotide dissociation inhibitor of G{alpha}i1. J Biol Chem 2010; 285:31647-60. [PMID: 20679342 PMCID: PMC2951237 DOI: 10.1074/jbc.m110.148429] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Indexed: 01/06/2023] Open
Abstract
Nucleobindin 1 (NUCB1) is a widely expressed multidomain calcium-binding protein whose precise physiological and biochemical functions are not well understood. We engineered and heterologously expressed a soluble form of NUCB1 (sNUCB1) and characterized its biophysical and biochemical properties. We show that sNUCB1 exists as a dimer in solution and that each monomer binds two divalent calcium cations. Calcium binding causes conformational changes in sNUCB1 as judged by circular dichroism and fluorescence spectroscopy experiments. Earlier reports suggested that NUCB1 might interact with heterotrimeric G protein α subunits. We show that dimeric calcium-free sNUCB1 binds to expressed Gα(i1) and that calcium binding inhibits the interaction. The binding of sNUCB1 to Gα(i1) inhibits its basal rate of GDP release and slows its rate and extent of GTPγS uptake. Additionally, our tissue culture experiments show that sNUCB1 prevents receptor-mediated Gα(i)-dependent inhibition of adenylyl cyclase. Thus, we conclude that sNUCB1 is a calcium-dependent guanine nucleotide dissociation inhibitor (GDI) for Gα(i1). To our knowledge, sNUCB1 is the first example of a calcium-dependent GDI for heterotrimeric G proteins. We also show that the mechanism of GDI activity of sNUCB1 is unique and does not arise from the consensus GoLoco motif found in RGS proteins. We propose that cytoplasmic NUCB1 might function to regulate heterotrimeric G protein trafficking and G protein-coupled receptor-mediated signal transduction pathways.
Collapse
Affiliation(s)
- Neeraj Kapoor
- From the Laboratory of Biochemistry and Molecular Biology, Rockefeller University, New York, New York 10065
| | - Ruchi Gupta
- From the Laboratory of Biochemistry and Molecular Biology, Rockefeller University, New York, New York 10065
| | - Santosh T. Menon
- From the Laboratory of Biochemistry and Molecular Biology, Rockefeller University, New York, New York 10065
| | - Ewa Folta-Stogniew
- the W. M. Keck Foundation Biotechnology Resource Laboratory, Yale University School of Medicine, New Haven, Connecticut 06520, and
| | - Daniel P. Raleigh
- the Department of Chemistry and
- Graduate Program in Biochemistry and Structural Biology and Graduate Program in Biophysics, State University of New York, Stony Brook, New York 11794
| | - Thomas P. Sakmar
- From the Laboratory of Biochemistry and Molecular Biology, Rockefeller University, New York, New York 10065
| |
Collapse
|
27
|
Zhuang X, Chowdhury S, Northup JK, Ray K. Sar1-dependent trafficking of the human calcium receptor to the cell surface. Biochem Biophys Res Commun 2010; 396:874-80. [PMID: 20457124 DOI: 10.1016/j.bbrc.2010.05.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Accepted: 05/04/2010] [Indexed: 01/03/2023]
Abstract
The molecular mechanisms underlying the exit from the endoplasmic reticulum (ER) for cell surface trafficking of the human calcium receptor (hCaR) remain poorly understood. We investigated the role of the Sar1 small GTP-binding protein in cell surface transport of the hCaR. Disruptions of endogenous Sar1 function with the constitutively active Sar1H79G mutant or depletion using small interfering RNA, attenuates cell surface expression of the hCaR. Mutation of several putative di-acidic ER export motifs in the carboxyl-tail of the receptor revealed no apparent defect in cell surface expression. Truncated mutants lacking most of the carboxyl-terminal sequences or all intracellular domains also showed no impairment in cell surface expression at steady state. A truncated receptor containing only the large amino-terminal extracellular ligand-binding domain (ECD) is secreted into the culture medium and Sar1H79G inhibits this secretion. ECD receptor variants with the cysteines essential for intermolecular disulfide-linked dimerization mutated to serine or four of the asparagine sites for N-glycosylation mutated to alanine also disrupt secretion, indicating proper ECD conformation is critical for forward transport of this receptor.
Collapse
Affiliation(s)
- Xiaolei Zhuang
- Laboratory of Cellular Biology, NIDCD, National Institutes of Health, Bethesda, MD 20892, USA
| | | | | | | |
Collapse
|
28
|
Aradhyam GK, Balivada LM, Kanuru M, Vadivel P, Vidhya BS. Calnuc: Emerging roles in calcium signaling and human diseases. IUBMB Life 2010; 62:436-46. [DOI: 10.1002/iub.341] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
|
29
|
Honoré B. Masking of signal sequences in CREC proteins by cDNA subcloning in epitope vectors. J Biol Chem 2009; 284:le13; author reply le14. [PMID: 19946061 DOI: 10.1074/jbc.l109.021592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
|