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Callea F, Giovannoni I, Francalanci P, Boldrini R, Faa G, Medicina D, Nobili V, Desmet VJ, Ishak K, Seyama K, Bellacchio E. Mineralization of alpha-1-antitrypsin inclusion bodies in Mmalton alpha-1-antitrypsin deficiency. Orphanet J Rare Dis 2018; 13:79. [PMID: 29769092 PMCID: PMC5956786 DOI: 10.1186/s13023-018-0821-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 05/08/2018] [Indexed: 02/07/2023] Open
Abstract
Background Alpha-1-antitrypsin (AAT) deficiency (AATD) of Z, Mmalton, Siiyama type is associated with liver storage of the mutant proteins and liver disease. The Z variant can be diagnosed on isoelectric focusing (IEF) while Mmalton and Siiyama may be missed or misdiagnosed with this technique. Therefore, molecular analysis is mandatory for their characterization. In particular, that holds true for the Mmalton variant as on IEF profile it resembles the wild M2 subtype. Methods This is a retrospective analysis involving review of medical records and of liver biopsy specimens from a series of Mmalton, Z and Siiyama Alpha-1-antitrypsin deficiency patients. The review has been implemented by additional histological stains, electron microscopic observations and 3-D modeling studies of the sites of the mutations. Results Z, Mmalton and Siiyama liver specimen contained characteristic intrahepatocytic PAS-D globules. The globules differed in the three variants as only Mmalton cases showed dark basophilic precipitates within the AAT inclusions. The precipitates were visualized in haematoxylin-eosin (H.E.) stained preparations and corresponded to calcium precipitates as demonstrated by von Kossa staining. On immunohistochemistry, ZAAT inclusions were stained by polyclonal as well as monoclonal noncommercial anti-AAT antibody (AZT11), whilst Mmalton and Siiyama inclusion bodies remained negative with the monoclonal anti-Z antibody. 3-D protein analysis allowed to predict more severe misfolding of the Mmalton molecule as compared to Z and Siiyama that could trigger anomalous interaction with endoplasmic reticulum chaperon proteins, namely calcium binding proteins. Conclusions Mmalton AAT inclusion bodies contain calcium precipitates inside them that allow the differential diagnosis with Siiyama and ZAAT inclusions in routine histological sections. The study has confirmed the specificity of the monoclonal AZT11 for the Z mutant. Thus, the combination of these two features is crucial for the distinction between the three variants and for predicting the genotype, whose confirmation would definitely require molecular analysis. Our study provides new data on the pathomorphogenesis of Mmalton inclusion bodies whose mineralization could play a central role in disease pathogenesis of Mmalton that is distinct from the Z and Siiyama variants. Calcium is known to be a major effector of cell death either via the increased intracellular concentration or the alteration of homeostasis.
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Affiliation(s)
- Francesco Callea
- Department of Pathology, Bambino Gesù Children's Hospital, IRCCS, Piazza S. Onofrio 4, 00165, Rome, Italy.
| | - Isabella Giovannoni
- Department of Pathology, Bambino Gesù Children's Hospital, IRCCS, Piazza S. Onofrio 4, 00165, Rome, Italy
| | - Paola Francalanci
- Department of Pathology, Bambino Gesù Children's Hospital, IRCCS, Piazza S. Onofrio 4, 00165, Rome, Italy
| | - Renata Boldrini
- Department of Pathology, Bambino Gesù Children's Hospital, IRCCS, Piazza S. Onofrio 4, 00165, Rome, Italy
| | - Gavino Faa
- Department of Cytomorphology, University of Cagliari, Cagliari, Italy
| | - Daniela Medicina
- Department of Pathology Spedali Civili, University of Brescia, Brescia, Italy
| | - Valerio Nobili
- Hepato-metabolic Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | | | - Kamal Ishak
- Armed Forces Institute of Pathology, Washington, USA
| | - Kuniaki Seyama
- Division of Respiratory Medicine, Juntendo University Faculty of Medicine and Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-Ku, Tokyo, 113-8421, Japan
| | - Emanuele Bellacchio
- Genetic and Rare Diseases, Research Division, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
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Wang Y, Huang X, Zhou J, Yang X, Li D, Mao H, Sun HH, Liu N, Lian J. Trafficking-deficient G572R-hERG and E637K-hERG activate stress and clearance pathways in endoplasmic reticulum. PLoS One 2012; 7:e29885. [PMID: 22242185 PMCID: PMC3252338 DOI: 10.1371/journal.pone.0029885] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 12/07/2011] [Indexed: 02/01/2023] Open
Abstract
Background Long QT syndrome type 2 (LQT2) is the second most common type of all long QT syndromes. It is well-known that trafficking deficient mutant human ether-a-go-go-related gene (hERG) proteins are often involved in LQT2. Cells respond to misfolded and trafficking-deficient proteins by eliciting the unfolded protein response (UPR) and Activating Transcription Factor (ATF6) has been identified as a key regulator of the mammalian UPR. In this study, we investigated the role of ER chaperone proteins (Calnexin and Calreticulin) in the processing of G572R-hERG and E637K-hERG mutant proteins. Methods pcDNA3-WT-hERG, pcDNA3-G572R-hERG and pcDNA3-E637K-hERG plasmids were transfected into U2OS and HEK293 cells. Confocal microscopy and western blotting were used to analyze subcellular localization and protein expression. Interaction between WT or mutant hERGs and Calnexin/Calreticulin was tested by coimmunoprecipitation. To assess the role of the ubiquitin proteasome pathway in the degradation of mutant hERG proteins, transfected HEK293 cells were treated with proteasome inhibitors and their effects on the steady state protein levels of WT and mutant hERGs were examined. Conclusion Our results showed that levels of core-glycosylated immature forms of G572R-hERG and E637K-hERG in association with Calnexin and Calreticulin were higher than that in WT-hERG. Both mutant hERG proteins could activate the UPR by upregulating levels of active ATF6. Furthermore, proteasome inhibition increased the levels of core-glycosylated immature forms of WT and mutant hERGs. In addition, interaction between mutant hERGs and Calnexin/Calreticulin was stronger after proteasome inhibition, compared to WT-hERG. These results suggest that trafficking-deficient G572R-hERG and E637K-hERG mutant proteins can activate ER stress pathways and are targeted to the proteasome for degradation. Calnexin and Calreticulin play important roles in these processes.
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Affiliation(s)
- Ying Wang
- Ningbo Medical Center, LiHuiLi Hospital School of Medicine, Ningbo University, Ningbo, China
| | - Xiaoyan Huang
- Ningbo Medical Center, LiHuiLi Hospital School of Medicine, Ningbo University, Ningbo, China
| | - Jianqing Zhou
- Ningbo Medical Center, LiHuiLi Hospital School of Medicine, Ningbo University, Ningbo, China
| | - Xi Yang
- Ningbo Medical Center, LiHuiLi Hospital School of Medicine, Ningbo University, Ningbo, China
| | - Di Li
- Ningbo Medical Center, LiHuiLi Hospital School of Medicine, Ningbo University, Ningbo, China
| | - Haiyan Mao
- Ningbo Medical Center, LiHuiLi Hospital School of Medicine, Ningbo University, Ningbo, China
| | - Huan Huan Sun
- Department of Surgery, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Ningsheng Liu
- Department of Pathology, Nanjing Medical University, Nanjing, China
- * E-mail: (JL); (NL)
| | - Jiangfang Lian
- Ningbo Medical Center, LiHuiLi Hospital School of Medicine, Ningbo University, Ningbo, China
- * E-mail: (JL); (NL)
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Wilson TJ, Gilfillan S, Colonna M. Fc Receptor-Like A Associates with Intracellular IgG and IgM but Is Dispensable for Antigen-Specific Immune Responses. THE JOURNAL OF IMMUNOLOGY 2010; 185:2960-7. [DOI: 10.4049/jimmunol.1001428] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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4
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Chen Y, Hoehenwarter W, Weckwerth W. Comparative analysis of phytohormone-responsive phosphoproteins in Arabidopsis thaliana using TiO2-phosphopeptide enrichment and mass accuracy precursor alignment. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 63:1-17. [PMID: 20374526 DOI: 10.1111/j.1365-313x.2010.04218.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Protein phosphorylation/dephosphorylation is a central post-translational modification in plant hormone signaling, but little is known about its extent and function. Although pertinent protein kinases and phosphatases have been predicted and identified for a variety of hormone responses, classical biochemical approaches have so far revealed only a few candidate proteins and even fewer phosphorylation sites. Here we performed a global quantitative analysis of the Arabidopsis phosphoproteome in response to a time course of treatments with various plant hormones using phosphopeptide enrichment and subsequent mass accuracy precursor alignment (MAPA). The use of three time points, 1, 3 and 6 h, in combination with five phytohormone treatments, abscisic acid (ABA), indole-3-acetic acid (IAA), gibberellic acid (GA), jasmonic acid (JA) and kinetin, resulted in 324,000 precursor ions from 54 LC-Orbitrap-MS analyses quantified and aligned in a data matrix with the dimension of 6000 x 54 using the ProtMax algorithm. To dissect the phytohormone responses, multivariate principal/independent components analysis was performed. In total, 152 phosphopeptides were identified as differentially regulated; these phosphopeptides are involved in a wide variety of signaling pathways. New phosphorylation sites were identified for ABA response element binding factors that showed a specific increase in response to ABA. New phosphorylation sites were also found for RLKs and auxin transporters. We found that different hormones regulate distinct amino acid residues of members of the same protein families. In contrast, tyrosine phosphorylation of the G alpha subunit appeared to be a common response for multiple hormones, demonstrating global cross-talk among hormone signaling pathways.
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Affiliation(s)
- Yanmei Chen
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
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5
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Guérin R, Turcotte C, Leroux A, Rokeach LA. The epigenetic calnexin-independent state is induced in response to environmental changes. FEMS Yeast Res 2009; 9:1250-9. [PMID: 19686339 DOI: 10.1111/j.1567-1364.2009.00554.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Yeasts have evolved numerous responsive pathways to survive in fluctuating and stressful environments. The endoplasmic reticulum (ER) is sensitive to adverse conditions, which are detected by response pathways to ensure correct protein folding. Calnexin is an ER transmembrane chaperone acting in both quality control of folding and response to persistent stress. Calnexin is a key protein required for viability in certain organisms such as mammals and the fission yeast Schizosaccharomyces pombe. Nevertheless, S. pombe calnexin-independent (Cin) cells were obtained after transient expression of a particular calnexin mutant. The Cin state is dominant, is stably propagated by an epigenetic mechanism and segregates in a non-Mendelian fashion to the meiotic progeny. The nucleolar protein Cif1p was identified as an inducer of the Cin state in a previous genetic screen. Here, we report the identification of novel inducers isolated in an overexpression genetic screen: pyruvate kinase (Pyk1p) and phosphoglycerate kinase (Pgk1p). Addition of pyruvate, the end product of pyruvate kinase and glycolysis, also induced calnexin independence in a dose-dependent manner. Remarkably, growth in respiration media or cold temperatures induced the appearance of Cin cells at high frequencies. Taken together, our results indicate that the Cin state can be triggered by extracellular changes, suggesting that this state represents an epigenetic adaptative response to environmental modifications.
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Affiliation(s)
- Renée Guérin
- Department of Biochemistry, Université de Montréal, Montréal, QC, Canada
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6
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Beauregard PB, Guérin R, Turcotte C, Lindquist S, Rokeach LA. A nucleolar protein allows viability in the absence of the essential ER-residing molecular chaperone calnexin. J Cell Sci 2009; 122:1342-51. [PMID: 19351719 DOI: 10.1242/jcs.040949] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
In fission yeast, the ER-residing molecular chaperone calnexin is normally essential for viability. However, a specific mutant of calnexin that is devoid of chaperone function (Deltahcd_Cnx1p) induces an epigenetic state that allows growth of Schizosaccharomyces pombe without calnexin. This calnexin-independent (Cin) state was previously shown to be mediated via a non-chromosomal element exhibiting some prion-like features. Here, we report the identification of a gene whose overexpression induces the appearance of stable Cin cells. This gene, here named cif1(+) for calnexin-independence factor 1, encodes an uncharacterized nucleolar protein. The Cin cells arising from cif1(+) overexpression (Cin(cif1) cells) are genetically and phenotypically distinct from the previously characterized Cin(Deltahcd_cnx1) cells, which spontaneously appear in the presence of the Deltahcd_Cnx1p mutant. Moreover, cif1(+) is not required for the induction or maintenance of the Cin(Deltahcd_cnx1) state. These observations argue for different pathways of induction and/or maintenance of the state of calnexin independence. Nucleolar localization of Cif1p is required to induce the Cin(cif1) state, thus suggesting an unexpected interaction between the vital cellular role of calnexin and a function of the nucleolus.
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Affiliation(s)
- Pascale B Beauregard
- Department of Biochemistry, Université de Montréal, C.P. 6128, succursale Centre-ville, Montréal, Québec H3C 3J7, Canada
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7
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Zhuang L, Scolyer RA, Lee CS, McCarthy SW, Cooper WA, Zhang XD, Thompson JF, Hersey P. Expression of glucose-regulated stress protein GRP78 is related to progression of melanoma. Histopathology 2009; 54:462-70. [DOI: 10.1111/j.1365-2559.2009.03242.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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8
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GTPase-mediated regulation of the unfolded protein response in Caenorhabditis elegans is dependent on the AAA+ ATPase CDC-48. Mol Cell Biol 2008; 28:4261-74. [PMID: 18458060 DOI: 10.1128/mcb.02252-07] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
When endoplasmic reticulum (ER) homeostasis is perturbed, an adaptive mechanism is triggered and named the unfolded protein response (UPR). Thus far, three known UPR signaling branches (IRE-1, PERK, and ATF-6) mediate the reestablishment of ER functions but can also lead to apoptosis if ER stress is not alleviated. However, the understanding of the molecular mechanisms integrating the UPR to other ER functions, such as membrane traffic or endomembrane signaling, remains incomplete. We consequently sought to identify new regulators of UPR-dependent transcriptional mechanisms and focused on a family of proteins known to mediate, among other, ER-related functions: the small GTP-binding proteins of the RAS superfamily. To this end, we used transgenic UPR reporter Caenorhabditis elegans strains as a model to specifically silence small-GTPase expression. We show that the Rho subfamily member CRP-1 is an essential component of UPR-induced transcriptional events through its physical and genetic interactions with the AAA+ ATPase CDC-48. In addition, we describe a novel signaling module involving CRP-1 and CDC-48 which may directly link the UPR to DNA remodeling and transcription control.
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9
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Abstract
The endoplasmic reticulum (ER) is the first sub-cellular compartment encountered by secretory proteins en route to the plasma membrane. Newly synthesized secretory proteins translocate into the ER lumen and acquire their correct conformation prior to being exported to later compartments. When folding is not properly achieved, proteins accumulate in the ER due to resident quality control machineries and terminally misfolded proteins are ultimately degraded through the ER-associated degradation pathway. All these molecular machines function in a coordinated fashion to restore and maintain ER homeostasis. A fifth molecular machine plays a coordinating role in the ER. Indeed, the ER stress signaling machinery signals ER dysfunction to the rest of the cell and consequently integrates the functions of the four other molecular machines to improve their operation in stressful conditions. In this work, we have attempted to define the ER as a molecular biological system regulated by its own specific signaling pathways defined as the Unfolded Protein Response to delineate a systems biology approach of ER stress signaling.
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10
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Lu Q, Harrington EO, Newton J, Jankowich M, Rounds S. Inhibition of ICMT induces endothelial cell apoptosis through GRP94. Am J Respir Cell Mol Biol 2007; 37:20-30. [PMID: 17347446 PMCID: PMC1899353 DOI: 10.1165/rcmb.2006-0301sm] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Isoprenylcysteine-O-carboxyl methyltransferase (ICMT) catalyzes methylation of proteins containing a C-terminal CAAX motif. We have previously shown that chemical inhibition of ICMT caused endothelial cell apoptosis, an effect correlated with decreased Ras and RhoA carboxyl methylation and GTPase activities. In the current study, proteomic analysis of pulmonary artery endothelial cells (PAEC) exposed to the ICMT inhibitor, N-acetyl-geranylgeranyl-cysteine (AGGC), demonstrated a shift in the isoelectric points (pI) of the glucose-regulated protein (GRP) 94. Two-dimensional PAGE and immunoblot analysis further documented that ICMT inhibition caused multiple changes in the pI of GRP94. GRP94 is an endoplasmic reticulum molecular chaperone, a component of the unfolded protein response (UPR), and is involved in apoptosis. Immunofluorescence analyses revealed redistribution and aggregation of GRP94 after 3 h exposure to AGGC. A similar finding was noted with calnexin. In addition, GRP94 protein levels were significantly diminished upon 18 h AGGC exposure or ICMT suppression. The effects of ICMT inhibition on changes in GRP94 subcellular localization and protein content were blunted by overexpression of constitutively active RhoA or a caspase inhibitor. Furthermore, GRP94 depletion augmented endothelial cell apoptosis induced by ICMT inhibition. These results indicate that ICMT inhibition leads to GRP94 relocalization, aggregation, and degradation; effects were dependent upon the activities of RhoA and caspases. We speculate that changes in the pI, subcellular localization, and protein level of GRP94 cause endothelial cell apoptosis, possibly through UPR dysfunction. These studies suggest a novel link between RhoA GTPases and the UPR.
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Affiliation(s)
- Qing Lu
- Providence VA Medical Center, Pulmonary/Critical Care Medicine Section, 830 Chalkstone Avenue, Providence, RI 02908, USA
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11
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Snapp EL, Sharma A, Lippincott-Schwartz J, Hegde RS. Monitoring chaperone engagement of substrates in the endoplasmic reticulum of live cells. Proc Natl Acad Sci U S A 2006; 103:6536-41. [PMID: 16617114 PMCID: PMC1458919 DOI: 10.1073/pnas.0510657103] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The folding environment in the endoplasmic reticulum (ER) depends on multiple abundant chaperones that function together to accommodate a range of substrates. The ways in which substrate engagement shapes either specific chaperone dynamics or general ER attributes in vivo remain unknown. In this study, we have evaluated how changes in substrate flux through the ER influence the diffusion of both the lectin chaperone calreticulin and an inert reporter of ER crowdedness. During acute changes in substrate load, the inert probe revealed no changes in ER organization, despite significant changes in calreticulin dynamics. By contrast, inhibition of the lectin chaperone system caused rapid changes in the ER environment that could be reversed over time by easing new substrate burden. Our findings provide insight into the normal organization and dynamics of an ER chaperone and characterize the capacity of the ER to maintain homeostasis during acute changes in chaperone activity and availability.
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Affiliation(s)
- Erik L Snapp
- Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, 18 Library Drive, Building 18, Room 101, Bethesda, MD 20892, USA.
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12
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Schmidt BZ, Perlmutter DH. Grp78, Grp94, and Grp170 interact with alpha1-antitrypsin mutants that are retained in the endoplasmic reticulum. Am J Physiol Gastrointest Liver Physiol 2005; 289:G444-55. [PMID: 15845869 DOI: 10.1152/ajpgi.00237.2004] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In alpha1-antitrypsin (alpha1-AT) deficiency, a mutant form of alpha1-AT polymerizes in the endoplasmic reticulum (ER) of liver cells resulting in chronic hepatitis and hepatocellular carcinoma by a gain of toxic function mechanism. Although some aspects of the cellular response to mutant alpha1-AT Z have been partially characterized, including the involvement of several proteasomal and nonproteasomal mechanisms for disposal, other parts of the cellular response pathways, particularly the chaperones with which it interacts and the signal transduction pathways that are activated, are still not completely elucidated. The alpha1-AT Z molecule is known to interact with calnexin, but, according to one study, it does not interact with Grp78. To carry out a systematic search for the chaperones with which alpha1-AT Z interacts in the ER, we used chemical cross-linking of several different genetically engineered cell systems. Mutant alpha1-AT Z was cross-linked with Grp78, Grp94, calnexin, Grp170, UDP-glucose glycoprotein:glucosyltransferase, and two unknown proteins of approximately 110-130 kDa. Sequential immunoprecipitation/immunoblot analysis and coimmunoprecipitation techniques demonstrated each of these interactions without chemical cross-linking. The same chaperones were found to interact with two nonpolymerogenic alpha1-AT mutants that are retained in the ER, indicating that these interactions are not specific for the alpha1-AT Z mutant. Moreover, sucrose density gradient centrifugation studies suggest that approximately 85% of alpha1-AT Z exists in heterogeneous soluble complexes with multiple chaperones and approximately 15% in extremely large polymers/aggregates devoid of chaperones. Agents that perturb the synthesis and/or activity of ER chaperones such as tunicamycin and calcium ionophore A23187, have different effects on the solubility and degradation of alpha1-AT Z as well as on its residual secretion.
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Affiliation(s)
- Bela Z Schmidt
- Department of Pediatrics, Univ. of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh, 3705 Fifth Ave., Pittsburgh, PA 15213-2583, USA
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13
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Hsu WM, Hsieh FJ, Jeng YM, Kuo ML, Tsao PN, Lee H, Lin MT, Lai HS, Chen CN, Lai DM, Chen WJ. GRP78 expression correlates with histologic differentiation and favorable prognosis in neuroblastic tumors. Int J Cancer 2005; 113:920-7. [PMID: 15514946 DOI: 10.1002/ijc.20693] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Glucose-regulated protein 78 (GRP78), an endoplasmic reticulum protein, is essential for the differentiation of neuroblastoma cells and is selectively induced when the cells are undergoing apoptosis. These findings suggest that GRP78 may affect the tumor behavior of neuroblastoma. Our study evaluates the association of clinicopathologic factors and patient survival with the expression of GRP78 in patients with neuroblastoma. GRP78 expression in 68 neuroblastic tumors was investigated semiquantitatively by immunohistochemistry. GRP78 mRNA and protein levels in 7 tumor tissues were also quantified by real-time PCR and Western blot respectively and correlated well with the immunohistochemical results. Forty (58.8%) of the 68 neuroblastic tumors showed positive GRP78 expression. The percentage of positive GRP78 immunostaining increased as the tumor histology became differentiated (p = 0.001). Furthermore, positive GRP78 expression strongly correlated with early clinical stages (P = 0.002) but inversely correlated with MYCN amplification (p = 0.001). Kaplan-Meier analysis showed that patients with positive GRP78 expression did have better survival than those with negative expression (5-year survival rate, 72.9% and 23.4% respectively, p < 0.001). Multivariate analysis further showed that GRP78 expression was an independent prognostic factor. Moreover, GRP78 expression predicted better survival in patients with either undifferentiated or differentiated histologies. GRP78 expression still had significant prognostic value when the analysis was restricted to tumors of advanced stages or without MYCN amplification. Thus, GRP78 can serve as a novel independent favorable prognostic factor for patients with neuroblastoma.
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Affiliation(s)
- Wen-Ming Hsu
- Department of Surgery, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
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Posey KL, Hayes E, Haynes R, Hecht JT. Role of TSP-5/COMP in pseudoachondroplasia. Int J Biochem Cell Biol 2004; 36:1005-12. [PMID: 15094116 DOI: 10.1016/j.biocel.2004.01.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2003] [Revised: 01/07/2004] [Accepted: 01/13/2004] [Indexed: 11/15/2022]
Abstract
Pseudoachondroplasia (PSACH) is a well-characterized dwarfing condition associated with disproportionate short stature, abnormal joints and osteoarthritis requiring joint replacement. PSACH is caused by mutations in cartilage oligomeric matrix protein (COMP). COMP, the fifth member of the thrombospondin (TSP) gene family, is a pentameric protein found primarily in the extracellular matrix of musculoskeletal tissues. Functional studies have shown that COMP binds types II and IX collagens but the role of COMP in the extracellular matrix remains to be defined. Mutations in COMP interfere with calcium-binding and protein conformation. PSACH growth plate and growth plate chondrocytes studies indicate that COMP mutations have a dominant negative effect with both COMP and type IX collagen being retained in large rER cisternae. This massive retention causes impaired chondrocyte function with little COMP secreted into the matrix and premature loss of chondrocytes. Deficiency of linear growth results from loss of chondrocytes from the growth plate. Secondarily, the matrix contains minimal COMP, which may be normal and/or mutant, and little type IX collagen. This deficiency results in abnormal joints that are easily eroded and cause painful osteoarthritis. Unlike other misfolded proteins that are targeted for degradation, much of the retained COMP escapes degradation, compromises cell function, and causes cell death. Gene therapy will need to target the reduction of COMP in order to restore normal chondrocyte function and longevity.
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Affiliation(s)
- Karen L Posey
- Department of Pediatrics, Medical School at Houston, University of Texas Health Science Center, 6431 Fannin, Room MSB 3.306, Houston, TX 77030, USA
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15
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McGovern VL, Pacak CA, Sewell ST, Turski ML, Seeger MA. A targeted gain of function screen in the embryonic CNS of Drosophila. Mech Dev 2004; 120:1193-207. [PMID: 14568107 DOI: 10.1016/s0925-4773(03)00159-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In order to identify genes involved in the development of the central nervous system (CNS) we have undertaken a gain of function screen in the embryonic CNS of Drosophila. Transposable P-elements and the UAS/GAL4 system were used to initiate transcription of genes in a pan-neural pattern using scaGAL4. Over 4100 individual P-element insertion lines were screened with monoclonal antibodies BP102 and 1D4 to visualize axon pathways. Twenty-five P-element insertions corresponding to 18 genes resulted in aberrant CNS axon pathfinding when misexpressed with scaGAL4. Genes involved in axon guidance, embryonic patterning, and cell cycle regulation were isolated. In addition, we identified several zinc finger transcription factors not previously implicated in axon guidance or CNS development. This group includes Squeeze, Kruppel homolog-1, Hepatocyte nuclear factor 4, and two uncharacterized genes, CG11966 and CG9650. Calnexin99A, a putative molecular chaperone, was isolated as well.
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Affiliation(s)
- Vicki L McGovern
- Department of Molecular Genetics and The Center for Molecular Neurobiology, 125 Rightmire Hall, The Ohio State University, 1060 Carmack Rd., Columbus, OH 43210, USA
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Abstract
The zona pellucida is an extracellular coat that surrounds mammalian eggs and early embryos. This insoluble matrix separates germ from somatic cells during folliculogenesis and plays critical roles during fertilization and early development. The mouse and human zona pellucida contain three glycoproteins (ZP1 or ZPB, ZP2, ZP3), the primary structures of which have been deduced by molecular cloning. Targeted mutagenesis of endogenous mouse genes and transgenesis with human homologues provide models to investigate the roles of individual zona components. Collectively, the genetic data indicate that no single mouse zona pellucida protein is obligatory for taxon-specific sperm binding and that two human proteins are not sufficient to support human sperm binding. An observed post-fertilization persistence of mouse sperm binding to "humanized" zona pellucida correlates with uncleaved ZP2. These observations are consistent with a model for sperm binding in which the supramolecular structure of the zona pellucida necessary for sperm binding is modulated by the cleavage status of ZP2.
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Affiliation(s)
- Jurrien Dean
- Laboratory of Cellular and Developmental Biology, NIDDK, Building 50, Room 3134, National Institutes of Health, 50 South Drive, Bethesda, Maryland 20892, USA.
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17
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Abstract
Genes that cause human disorders in N-linked oligosaccharide biosynthesis have appeared much faster than animal model systems to study them. In most models, a single gene is altered or deleted while other genes and the environment are held constant. Since humans have variable genetic backgrounds and environments, model systems may only partially mimic the actual disorders. Mutations in seven of the 30-40 genes needed for the synthesis and transfer of oligosaccharides from the lipid donor to the nascent protein acceptors in the endoplasmic reticulum cause Type I Congenital Disorders of Glycosylation (CDG). Since all of these gene products ultimately contribute to the same final step, one might suspect that all the diseases would be very similar. However, even patients with mutations in the same gene show considerable phenotypic variability. Modifier, or susceptibility genes in the background likely explain some variations of the "primary" gene chosen for study. Add to this the stress of infections, dietary insufficiencies, and the demands of growth itself. These issues are particularly important during development when the temporal and spatial specific interplay of cell adhesions and signals has only a single opportunity. Multiple hypomorphic alleles of genes in the same pathway may have synergistic effects. Investigators designing model systems to study human glycosylation disorders may want to construct strains with several heterozygous hypomorphic alleles in rate-limiting steps in the glycosylation pathway.
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Affiliation(s)
- Hudson H Freeze
- Glycobiology and Carbohydrate Chemistry Program, The Burnham Institute, La Jolla, CA 92037, USA.
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18
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Arya P, Barkley A, Randell KD. Automated high-throughput synthesis of artificial glycopeptides. Small-molecule probes for chemical glycobiology. JOURNAL OF COMBINATORIAL CHEMISTRY 2002; 4:193-8. [PMID: 12005477 DOI: 10.1021/cc020001i] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A fully automated method for the synthesis of artificial glycopeptides having two (similar or different) carbon-linked glycosyl moieties on a dipeptide scaffold has been developed. By use of this approach that combines the diversity of peptide/pseudopeptide and glycosides, different glycoside moieties can be incorporated onto the peptide/pseudopeptide backbone in a highly controlled manner. The approach utilizes a stepwise reductive amination with glycoside aldehyde derivatives (model 1) or (ii) glycoside reductive amination followed by glycoside amide bond formation (model 2). Further, an automated method has been utilized in the high-throughput library synthesis of 4 x 96 artificial glycopeptides. These libraries were tested as chemical probes/inhibitors of enzyme systems that convert a glucose moiety into rhamnose prior to incorporation of the rhamnose unit and the conversion of UDP-galactopyranose to UDP-galactofuranose via UDP-galactopyranose mutase enzyme during the biosynthesis of the mycobacterium cell wall.
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Affiliation(s)
- Prabhat Arya
- Chemical Biology Program, Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario, K1A 0R6, Canada.
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19
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Poland J, Schadendorf D, Lage H, Schnölzer M, Celis JE, Sinha P. Study of therapy resistance in cancer cells with functional proteome analysis. Clin Chem Lab Med 2002; 40:221-34. [PMID: 12005211 DOI: 10.1515/cclm.2002.037] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Different types of cancer are naturally resistant to many anticancer drugs. Additionally, these tumours develop acquired drug resistance, which includes the classical multidrug resistance (MDR) accompanied by the synthesis of P-glycoprotein, a member of the superfamily of ATP-binding cassette (ABC) transporters. Furthermore, atypical MDR is mediated by several different, some unknown, mechanisms. To overcome chemoresistance problems, antineoplastic drugs are often combined with other modes of therapy, e.g. hyperthermia, where good response has been reported in several experimental tumour models and in advanced cancer patients. The success of this combined anticancer treatment may be limited by an increase in chemoresistance and thermoresistance. A model system to study resistance phenomena is the use of chemoresistant and thermoresistant cancer cell lines. We have established chemoresistant cancer cell lines (gastric and pancreatic carcinoma, fibrosarcoma, melanoma) and now thermoresistant cell lines derived from gastric and pancreatic carcinoma cells and their counterparts that were resistant towards daunorubicin (classical MDR) and mitoxantrone (atypical MDR). Using proteomics, in this paper we evaluate the drug resistance of chemoresistant melanoma cells (parental cell line MeWo and sublines exhibiting drug resistance towards etoposide, cisplatin, fotemustine and vindesine) as a paradigm for analysis of drug resistance phenomena. Additionally, we investigate heat resistance and the interaction of chemoresistance and thermoresistance to identify common pathways using the parental and drug resistant stomach cancer cell lines EPG85-257, EPG85-257RNOV, EPG85-257RDB and their thermoresistant counterparts. Possible implications of differential protein expression will be discussed.
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Affiliation(s)
- Julia Poland
- Institut für Laboratoriumsmedizin und Pathobiochemie, Universitätsklinikum Charité, Berlin, Germany
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20
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Ikawa M, Nakanishi T, Yamada S, Wada I, Kominami K, Tanaka H, Nozaki M, Nishimune Y, Okabe M. Calmegin is required for fertilin alpha/beta heterodimerization and sperm fertility. Dev Biol 2001; 240:254-61. [PMID: 11784061 DOI: 10.1006/dbio.2001.0462] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Loss of the endoplasmic reticulum resident chaperone calmegin leads to the production of sterile sperm that do not bind to the egg zona pellucida (M. Ikawa et al., 1997, Nature 387, 607-611). In the present study, we demonstrate that calmegin -/- sperm were defective in migrating into the oviducts and in binding to the egg plasma membrane. Despite the impaired adhesive function, calmegin -/- sperm could fertilize eggs when zonae pellucidae were partially dissected, and eggs fertilized in this manner could develop normally to term. Since these sperm characteristics were similar to those found in fertilin beta -/- sperm, we investigated the interaction of calmegin with fertilin beta. Using immunoprecipitation techniques, calmegin was found to bind to sperm membrane proteins, fertilin alpha and beta, during spermatogenesis. The binding was specific to calmegin: another endoplasmic reticulum chaperone calnexin, a calmegin homologue, was not able to bind to fertilin alpha and beta. In the calmegin -/- mice, a loss of heterodimerization of fertilin alpha and beta was observed and fertilin beta was not detectable in mature sperm. The data not only explain why the calmegin and fertilin beta knockout mouse lines share a common infertile phenotype, but also reveal the importance of the maturation of sperm membrane proteins in the endoplasmic reticulum.
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Affiliation(s)
- M Ikawa
- Genome Information Research Center, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
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21
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Farmery MR, Bulleid NJ. Major histocompatibility class I folding, assembly, and degradation: a paradigm for two-stage quality control in the endoplasmic reticulum. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2001; 67:235-68. [PMID: 11525384 DOI: 10.1016/s0079-6603(01)67030-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Protein folding in living cells is a complex process involving many interdependent factors. The primary site for folding of nascent proteins destined for secretion is the endoplasmic reticulum (ER). Several disease states, including cystic fibrosis, are brought about because of irregularities in protein folding. Under normal cellular conditions, "quality control" mechanisms ensure that only correctly folded proteins are exported from the ER, with incorrectly folded or incompletely assembled proteins being degraded. Quality control mechanisms can be divided into two broad processes: (1) Primary quality control involves general mechanisms that are not specific for individual proteins; these monitor the fidelity of nascent protein folding in the ER and mediate the destruction of incompletely folded proteins. (2) Partially folded or assembled proteins may be subject to secondary quality control mechanisms that are protein- or protein-family-specific. Here we use the folding and assembly of major histocompatibility complex (MHC) class I as an example to illustrate the processes of quality control in the ER. MHC class I, a trimeric complex assembled in the ER of virally infected or malignant cells, presents antigenic peptide to cytotoxic T lymphocytes; this mediates cell killing and thereby prevents the spread of infection or malignancy. The folding and assembly of MHC class I is subjected to both primary and secondary quality control mechanisms that lead either to correct folding, assembly, and secretion or to degradation via a proteasome-associated mechanism.
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Affiliation(s)
- M R Farmery
- University of Manchester, School of Biological Sciences, United Kingdom
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22
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Sinha P, Poland J, Schnölzer M, Celis JE, Lage H. Characterization of the differential protein expression associated with thermoresistance in human gastric carcinoma cell lines. Electrophoresis 2001; 22:2990-3000. [PMID: 11565793 DOI: 10.1002/1522-2683(200108)22:14<2990::aid-elps2990>3.0.co;2-f] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Resistance to chemotherapeutic agents is one of the major problems faced during palliative therapy of tumor cells. Thus, chemotherapy is frequently combined with other modes of therapy such as radiation therapy and/or hyperthermia. Tumor cells respond to heat stress with development of thermotolerance and the interactions between chemo- and thermoresistance phenomena are not clearly understood. In this paper, we analyze the differential protein expression in vitro in human stomach cancer cells, their chemoresistant and thermoresistant counterparts using proteomics. The immediate aim was to identify sets of proteins that may lead to the development of thermoresistance. Based on these results, we aim to develop functional tests and methods for the modulation of thermoresistance and chemoresistance phenomena that may assist the therapy of inoperable cancers.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- Blotting, Western
- Carcinoma/metabolism
- Carcinoma/pathology
- Drug Resistance, Neoplasm/genetics
- Electrophoresis, Gel, Two-Dimensional
- Gene Expression Profiling
- Gene Expression Regulation, Neoplastic
- Hot Temperature
- Humans
- Hyperthermia, Induced
- Neoplasm Proteins/biosynthesis
- Neoplasm Proteins/genetics
- Neoplasm Proteins/physiology
- Proteome
- Silver Staining
- Stomach Neoplasms/metabolism
- Stomach Neoplasms/pathology
- Tumor Cells, Cultured/chemistry
- Tumor Cells, Cultured/drug effects
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Affiliation(s)
- P Sinha
- Institut für Laboratoriumsmedizin und Pathobiochemie, Universitätsklinikum Charité, Berlin, Germany.
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23
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Chevet E, Cameron PH, Pelletier MF, Thomas DY, Bergeron JJ. The endoplasmic reticulum: integration of protein folding, quality control, signaling and degradation. Curr Opin Struct Biol 2001; 11:120-4. [PMID: 11179901 DOI: 10.1016/s0959-440x(00)00168-8] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The endoplasmic reticulum is the entry point into the secretory pathway. To acquire a correct conformation, secretory proteins encounter the endoplasmic reticulum molecular machines of folding, quality control, signaling and disposal, which function as an integrated mechanism. The creation of such a molecular network, spatially regulated, suggests how the endoplasmic reticulum promotes the release of correctly folded secretory proteins.
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Affiliation(s)
- E Chevet
- Anatomy and Cell Biology, McGill University, Montreal, Quebec, H3A 2B2, Canada
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24
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Abstract
Evidence is accumulating that intracellular animal lectins play important roles in quality control and glycoprotein sorting along the secretory pathway. Calnexin and calreticulin in conjunction with associated chaperones promote correct folding and oligomerization of many glycoproteins in the endoplasmic reticulum (ER). The mannose lectin ERGIC-53 operates as a cargo receptor in transport of glycoproteins from ER to Golgi and the homologous lectin VIP36 may operate in quality control of glycosylation in the Golgi. Exit from the Golgi of lysosomal hydrolases to endosomes requires mannose 6-phosphate receptors and exit to the apical plasma membrane may also involve traffic lectins. Here we discuss the features of these lectins and their role in glycoprotein traffic in the secretory pathway.
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Affiliation(s)
- H Hauri
- Department of Pharmacology, Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056, Basel, Switzerland.
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