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BACKGROUND: Interest in the issue of childhood autism has surged in the recent decades. At the same time, despite the significant progress achieved in understanding the etiological and pathogenetic aspects of the condition, effective ways to treat it have continued to elude us. Stem cell therapy appears to hold great promise in the treatment and rehabilitation of patients with both neurological diseases (cerebral palsy, hydrocephalus) and mental disorders (autism, schizophrenia). METHODS: This article presents a case report describing the use of nucleated cord blood cells in a patient with regressive autism and resistance to standard therapies. The child's condition was assessed before treatment and 6 and 12 months after. RESULTS: Clinical observation, psychometric, and instrumental diagnostic methods led to a significant improvement in the child's condition in the form of perception development, reduction of somatosensory disorders, normalization of emotional status, and a development of social and communication skills. CONCLUSION: We assume that the result obtained may be associated with the normalization of the immunological status of our patient thanks to the cord blood cells therapy and consider it necessary to conduct further studies into the effectiveness of the method, taking the pathogenic mechanisms of autism into account.
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BACKGROUND AIMS: The term "cerebral palsy" (CP) encompasses many syndromes that emerge from brain damage at early stages of ontogenesis and manifest as the inability to retain a normal body position or perform controlled movements. Existing methods of CP treatment, including various rehabilitation strategies and surgical and pharmacological interventions, are mostly palliative, and there is no specific therapy focused on restoring injured brain function. METHODS: During a post-registration clinical investigation, the safety and efficacy of intravenous infusion of allogeneic human leukocyte antigen (HLA)-unmatched umbilical cord blood (UCB) cells were studied in 80 pediatric patients with cerebral palsy and associated neurological complications. Patients received up to 6 intravenous infusions of AB0/Rh-identical, red blood cell-depleted UCB cells at an average dose of 250 × 10(6) viable cells per infusion. RESULTS: Patients were followed for 3-36 months, and multiple cell infusions did not cause any adverse effects. In contrast, in most patients who received four or more UCB cell infusions, positive dynamics related to significant improvements in neurological status and/or cognitive functions were observed. CONCLUSIONS: The results confirm that multiple intravenous infusions of allogeneic AB0/Rh-identical UCB cells may be a safe and effective procedure and could be included in treatment and rehabilitation programs for juvenile patients with cerebral palsy.
Assuntos
Terapia Baseada em Transplante de Células e Tecidos/métodos , Paralisia Cerebral/terapia , Transplante de Células-Tronco de Sangue do Cordão Umbilical/métodos , Sangue Fetal/transplante , Sistema ABO de Grupos Sanguíneos/imunologia , Criança , Pré-Escolar , Feminino , Antígenos HLA/imunologia , Humanos , Lactente , Infusões Intravenosas , Masculino , Sistema do Grupo Sanguíneo Rh-Hr/imunologia , Transplante HomólogoRESUMO
The aim of this study was to assess the involvement of eosinophil cationic protein, a marker of eosinophil activation, in the development of in-stent restenosis after drug-eluting stent implantation. Follow-up angiography at 6 to 12 months was performed in 32 patients who were treated with percutaneous coronary intervention and implantation of sirolimus-eluting stents. Blood plasma levels of eosinophil cationic protein (ECP) and total immunoglobulin E (IgE) were measured by enzyme-linked immunosorbent assay and the level of C-reactive protein (hs-CRP) by high-sensitivity nephelometry. According to angiography data, in-stent restenosis occurred in 13 patients, while 19 patients did not develop it. There were no differences between the hs-CRP and IgE levels in patients with or without restenosis. In contrast, ECP level was higher in patients with restenosis compared with that in patients without restenosis [17.7 ng/mL (11.2-24.0) vs. 9.0 ng/mL (6.4-12.9), p = 0.017]. The incidence of in-stent restenoses was 63% in patients with ECP level higher than or equal to 11 ng/mL, and 19% in patients with an ECP level lower than 11 ng/mL (p = 0.019). These findings suggest that elevated eosinophil activation may play an important role in the pathogenesis of in-stent restenosis after implantation of drug-eluting stents.
Assuntos
Reestenose Coronária/etiologia , Stents Farmacológicos , Proteína Catiônica de Eosinófilo/sangue , Imunossupressores/uso terapêutico , Revascularização Miocárdica/métodos , Sirolimo/uso terapêutico , Idoso , Biomarcadores/sangue , Proteína C-Reativa/análise , Angiografia Coronária , Reestenose Coronária/sangue , Reestenose Coronária/diagnóstico por imagem , Feminino , Seguimentos , Humanos , Imunoglobulina E/sangue , Masculino , Pessoa de Meia-Idade , Resultado do TratamentoRESUMO
In eukaryotic cells amyloid aggregates may incorporate various functionally unrelated proteins. In mammalian diseases this may cause amyloid toxicity, while in yeast this could contribute to prion phenotypes. Insolubility of amyloids in the presence of strong ionic detergents, such as SDS or sarcosyl, allows discrimination between amorphous and amyloid aggregates. Here, we used this property of amyloids to study the interdependence of their formation in yeast. We observed that SDS-resistant polymers of proteins with extended polyglutamine domains caused the appearance of SDS or sarcosyl-insoluble polymers of three tested chromosomally-encoded Q/N-rich proteins, Sup35, Rnq1 and Pub1. These polymers were non-heritable, since they could not propagate in the absence of polyglutamine polymers. Sup35 prion polymers caused the appearance of non-heritable sarcosyl-resistant polymers of Pub1. Since eukaryotic genomes encode hundreds of proteins with long Q/N-rich regions, polymer interdependence suggests that conversion of a single protein into polymer form may significantly affect cell physiology by causing partial transfer of other Q/N-rich proteins into a non-functional polymer state.
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Amiloide/metabolismo , Doenças Neurodegenerativas/metabolismo , Peptídeos/metabolismo , Saccharomyces cerevisiae/metabolismo , Amiloide/genética , Fatores de Terminação de Peptídeos/genética , Fatores de Terminação de Peptídeos/metabolismo , Proteínas de Ligação a Poli(A)/genética , Proteínas de Ligação a Poli(A)/metabolismo , Príons/genética , Príons/metabolismo , Multimerização Proteica , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismoRESUMO
BACKGROUND: Termination of translation in eukaryotes is controlled by two interacting polypeptide chain release factors, eRF1 and eRF3. While eRF1 recognizes nonsense codons, eRF3 facilitates polypeptide chain release from the ribosome in a GTP-dependent manner. Besides termination, both release factors have essential, but poorly characterized functions outside of translation. RESULTS: To characterize further the functions of yeast eRF1 and eRF3, a genetic screen for their novel partner proteins was performed. As a result, the genes for gamma (TEF4 and TEF3/CAM1) and alpha (TEF5/EFB1) subunits of the translation elongation factor eEF1B, known to catalyze the exchange of bound GDP for GTP on eEF1A, were revealed. These genes act as dosage suppressors of a synthetic growth defect caused by some mutations in the SUP45 and SUP35 genes encoding eRF1 and eRF3, respectively. Extra copies of TEF5 and TEF3 can also suppress the temperature sensitivity of some sup45 and sup35 mutants and reduce nonsense codon readthrough caused by these omnipotent suppressors. Besides, overproduction of eEF1Balpha reduces nonsense codon readthrough in the strain carrying suppressor tRNA. Such effects were not shown for extra copies of TEF2, which encodes eEF1A, thus indicating that they were not due to eEF1A activation. CONCLUSION: The data obtained demonstrate involvement of the translation elongation factor eEF1B in modulating the functions of translation termination factors and suggest its possible role in GDP for GTP exchange on eRF3.
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Terminação Traducional da Cadeia Peptídica , Fator 1 de Elongação de Peptídeos/metabolismo , Fatores de Terminação de Peptídeos/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Guanosina Difosfato/metabolismo , Guanosina Trifosfato/metabolismo , Saccharomyces cerevisiae/genéticaRESUMO
Peripheral blood contents of osteonectin-positive progenitor cells and polymorphonuclear granulocytes were examined by flow cytometry in 38 patients after myocardial revascularisation with drug-eluting stents. Repeat coronary angiography performed 6-12 months after stent implantation revealed in-stent restenosis in 15 patients and its absence in 23 patients. The plasma levels of osteonectin-positive progenitor cells, neutrophils, and basophils did not differ in patients with and without restenosis. Eosinophil blood levels in patients with and without restenosis were 262+/-68 and 124+/-67 cells/microL (mean+/-SD, p<0.001), respectively. Only one of 19 patients (5%) with eosinophil content lower than the distribution median for the entire group developed restenosis, whereas in the group with eosinophil contents higher than the median (n=19) restenosis occurred in 14 patients (74%, p<0.001). Our findings suggest that the frequency of restenoses after stenting is related to high peripheral blood eosinophil content.
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Angioplastia Coronária com Balão/efeitos adversos , Doença da Artéria Coronariana/terapia , Reestenose Coronária/etiologia , Stents Farmacológicos , Eosinofilia/etiologia , Neutrófilos/metabolismo , Osteonectina/sangue , Adulto , Idoso , Angioplastia Coronária com Balão/instrumentação , Estudos de Casos e Controles , Angiografia Coronária , Doença da Artéria Coronariana/sangue , Doença da Artéria Coronariana/diagnóstico por imagem , Reestenose Coronária/sangue , Reestenose Coronária/diagnóstico por imagem , Eosinofilia/sangue , Feminino , Citometria de Fluxo , Humanos , Contagem de Leucócitos , Masculino , Pessoa de Meia-Idade , Inibidores da Agregação Plaquetária/uso terapêutico , Fatores de Tempo , Resultado do TratamentoRESUMO
The level of circulating stromal progenitor cells carrying osteonectin (ON), a marker of osteogenic differentiation, was evaluated by flow cytometry in blood of patients with coronary artery disease (CAD). Ninety-nine patients with CAD were included into the study. Coronary angiography of all patients showed critical stenosis of at least 2 coronary arteries or their major branches. The control groups included 8 patients without CAD and 19 healthy volunteers. In control patients, no lesions of the coronary bed were found by angiography. The absence of CAD in the volunteers was confirmed by bicycle stress test. The content of ON-positive cells in blood was examined in various populations of lymphocyte-like cells. It was found that the number of ON+ lymphocyte-like cells with CD41 positivity in blood of patients without coronary stenosis (0.27%+/-0.11%, mean+/-SD) did not differ significantly from corresponding value in healthy volunteers (0.26%+/-0.07%, p=0.94). In CAD patients, the percent of these ON+ cells was 1.01%+/-0.49% and was significantly higher than in blood of healthy volunteers (p<0.0001) and patients without CAD (p<0.0001). High content of ON+ lymphocyte-like cells with CD41 positivity in blood may serve as noninvasive marker of arterial atherosclerosis.
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Doença da Artéria Coronariana/metabolismo , Estenose Coronária/metabolismo , Osteonectina/metabolismo , Células-Tronco/metabolismo , Adulto , Idoso , Biomarcadores/metabolismo , Feminino , Humanos , Antígenos Comuns de Leucócito/metabolismo , Masculino , Pessoa de Meia-Idade , Glicoproteína IIb da Membrana de Plaquetas/metabolismo , Células-Tronco/citologiaRESUMO
Chemotherapy continues to be the main therapeutic approach in the treatment of hematological malignancies including acute leukemia. Generally, chemotherapy is used to eliminate cancer cells and to restore normal bone marrow function. Simultaneous action of cytostatic drugs on bone marrow angiogenesis decreases the formation of new capillaries and improves therapeutic effect. However, chemotherapeutic agents may also be cytodestructive for cellular elements of other tissues, particularly the vascular endothelium, which can lead to various cardiovascular complications. In this work, we studied the effects of 2 cytostatic drugs, cytosine arabinoside (ara-C) and daunorubicin (DNR), on cultured human vascular (i.e., umbilical) endothelial cells (ECs). Ara-C and DNR were added to cultured cells at concentrations ranging from 1 ng/mL to 100 microg/mL. Drug effects were studied using phase-contrast microscopy, cell viability tests, BRDU incorporation, immunohistochemistry, flow cytometry, and cell cloning. At various concentrations, ara-C and DNR are able to induce morphological and functional changes in cultured cells related to either cytostatic or cytotoxic action. Moreover, ara-C-treated cultured cells displayed significant disturbances in cell adhesion molecule expression and interaction with blood leukocytes. Preliminary data obtained on acute leukemia patients undergoing standard cytostatic therapy ("7+3" regimen) have shown that concentration of the circulating ECs was significantly increased compared with the control group and could be as high as 500-1500 cells/mL of blood. Results obtained suggest that anticancer chemotherapy may induce systemic damage of vascular endothelium related to massive cell loss and (or) alterations of endothelial function.
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Antineoplásicos/farmacologia , Citarabina/farmacologia , Daunorrubicina/farmacologia , Células Endoteliais/efeitos dos fármacos , Adesão Celular/efeitos dos fármacos , Moléculas de Adesão Celular/metabolismo , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Endoteliais/citologia , Células Endoteliais/metabolismo , Endotélio Vascular/citologia , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/metabolismo , Humanos , Leucócitos/citologiaRESUMO
BACKGROUND: Termination of translation in eukaryotes requires two release factors, eRF1, which recognizes all three nonsense codons and facilitates release of the nascent polypeptide chain, and eRF3 stimulating translation termination in a GTP-depended manner. eRF3 from different organisms possess a highly conservative C region (eRF3C), which is responsible for the function in translation termination, and almost always contain the N-terminal extension, which is inessential and vary both in structure and length. In the yeast Saccharomyces cerevisiae the N-terminal region of eRF3 is responsible for conversion of this protein into the aggregated and functionally inactive prion form. RESULTS: Here, we examined functional importance of the N-terminal region of a non-prion form of yeast eRF3. The screen for mutations which are lethal in combination with the SUP35-C allele encoding eRF3C revealed the sup45 mutations which alter the N-terminal domain of eRF1 and increase nonsense codon readthrough. However, further analysis showed that synthetic lethality was not caused by the increased levels of nonsense codon readthrough. Dominant mutations in SUP35-C were obtained and characterized, which remove its synthetic lethality with the identified sup45 mutations, thus indicating that synthetic lethality was not due to a disruption of interaction with proteins that bind to this eRF3 region. CONCLUSION: These and other data demonstrate that the N-terminal region of eRF3 is involved both in modulation of the efficiency of translation termination and functioning of the eRF1/eRF3 complex outside of translation termination.
Assuntos
Terminação Traducional da Cadeia Peptídica/genética , Fatores de Terminação de Peptídeos/genética , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/genética , Alelos , Códon de Terminação/genética , Mutação/genética , Terminação Traducional da Cadeia Peptídica/fisiologia , Fatores de Terminação de Peptídeos/química , Fatores de Terminação de Peptídeos/metabolismo , Príons/genética , Ligação Proteica/fisiologia , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Deleção de Sequência/genéticaRESUMO
We used electron microscopic immunocytochemistry to examine the pattern of centriolar staining for tyrosinated or acetylated alpha-tubulin in endothelial cells during short-term incubation with thrombin. Endothelial cells isolated from human aorta (HAEC) and those isolated from umbilical vein (HUVEC) displayed an increase in the intensity of centriolar staining for acet-tubulin within 1 min after thrombin addition. A decrease in the intensity of centriolar staining for tyr-tubulin was detected in HUVEC within 1 min after thrombin addition, while in HAEC centriolar staining for tyr-tubulin became less intense only 5 min later. Mother and daughter centrioles of HUVEC cells displayed different intensity of immunostaining for acet-tubulin and showed no significant variation in the number of subdistal appendages after thrombin addition. Differently, HAEC cells had the same staining pattern of mother and daughter centrioles in both thrombin-untreated and thrombin-treated cultures. A sharp increase in the number of subdistal appendages of mother centriole occurred in HAEC within 5 min of incubation with thrombin. Our findings provided the direct evidence for centrosome involvement in the ligand-mediated signaling events and showed for the first time that ligand-dependent centrosome reorganization includes the centriole per se. Furthermore, based on our observations we would like to propose that MT-nucleating/anchoring properties of the centrosome are subject to rapid regulation by external signals such as thrombin.
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Centríolos/efeitos dos fármacos , Células Endoteliais/efeitos dos fármacos , Trombina/farmacologia , Tubulina (Proteína)/efeitos dos fármacos , Tirosina/química , Acetilação , Aorta/efeitos dos fármacos , Células Cultivadas , Centríolos/ultraestrutura , Humanos , Técnicas Imunoenzimáticas , Imuno-Histoquímica , Microscopia Imunoeletrônica , Processamento de Proteína Pós-Traducional , Veias Umbilicais/citologiaRESUMO
Using autopsy specimens and clonal technique, the authors showed that hematopoietic and stromal stem colony-forming units are present in human atheromatous vascular intima. Stromal colony-forming units were also detected in the mononuclear fraction of the blood of patients with hyperlipidemia and coronary stenosis, and were not found in the peripheral blood of normolipidemic volunteers. Using flow cytometry, the absence of stromal circulating colony-forming units in healthy volunteers and their presence in coronary patients was confirmed. It was thought that the presence of circulating stromal precursors with a certain phenotype and variations in their level in blood could serve as an informative noninvasive indicator of coronary stenosis.
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The [PSI+] prion determinant of Saccharomyces cerevisiae causes nonsense suppressor phenotype due to a reduced function of the translation termination factor Sup35 (eRF3) polymerized into amyloid fibrils. Prion state of the Rnq1 protein, [PIN+], is required for the [PSI+] de novo generation but not propagation. Yeast [psi-] [PIN+] cells overproducing Sup35 can exhibit nonsense suppression without generation of a stable [PSI+]. Here, we show that in such cells, most of Sup35 represents amyloid polymers, although the remaining Sup35 monomer is sufficient for normal translation termination. The presence of these polymers strictly depends on [PIN+], suggesting that their maintenance relies on efficient generation de novo rather than inheritance. Sup35 polymers contain Rnq1, confirming a hypothesis that Rnq1 polymers seed Sup35 polymerization. About 10% of cells overproducing Sup35 form colonies on medium selective for suppression, which suggests that the proportion of Sup35 monomers to polymers varies between cells of transformants, allowing selection of cells deficient for soluble Sup35. A hybrid Sup35 with the N-terminal domain replaced for 66 glutamine residues also polymerizes and can cause nonsense suppression when overproduced. The described polymers of these proteins differ from the [PSI+] polymers by poor heritability and very high frequency of the de novo appearance, thus being more similar to amyloids than to prions.
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Regulação Fúngica da Expressão Gênica , Príons/genética , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/genética , Códon/genética , Fatores de Terminação de Peptídeos , Príons/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismoRESUMO
In eukaryotic cells, COPI vesicles retrieve resident proteins to the endoplasmic reticulum and mediate intra-Golgi transport. Here, we studied the Hansenula polymorpha homologue of the Saccharomyces cerevisiae RET1 gene, encoding alpha-COP, a subunit of the COPI protein complex. H. polymorpha ret1 mutants, which expressed truncated alpha-COP lacking more than 300 C-terminal amino acids, manifested an enhanced ability to secrete human urokinase-type plasminogen activator (uPA) and an inability to grow with a shortage of Ca2+ ions, whereas a lack of alpha-COP expression was lethal. The alpha-COP defect also caused alteration of intracellular transport of the glycosylphosphatidylinositol-anchored protein Gas1p, secretion of abnormal uPA forms, and reductions in the levels of Pmr1p, a Golgi Ca2+-ATPase. Overexpression of Pmr1p suppressed some ret1 mutant phenotypes, namely, Ca2+ dependence and enhanced uPA secretion. The role of COPI-dependent vesicular transport in cellular Ca2+ homeostasis is discussed.
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Cálcio/metabolismo , Proteína Coatomer/metabolismo , Pichia/metabolismo , Sequência de Aminoácidos , Transporte Biológico , Western Blotting , ATPases Transportadoras de Cálcio/metabolismo , Clonagem Molecular , Retículo Endoplasmático/metabolismo , Glicosilfosfatidilinositóis/metabolismo , Complexo de Golgi/enzimologia , Complexo de Golgi/metabolismo , Humanos , Immunoblotting , Glicoproteínas de Membrana/metabolismo , Modelos Genéticos , Chaperonas Moleculares , Dados de Sequência Molecular , Mutação , Fenótipo , Plasmídeos/metabolismo , Estrutura Terciária de Proteína , Proteínas/metabolismo , RNA/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Homologia de Sequência de Aminoácidos , Ativador de Plasminogênio Tipo Uroquinase/metabolismoRESUMO
Mesenchymal stem cells (MSCs) have the capability for renewal and differentiation into various lineages of mesenchymal tissues. These features of MSCs attract a lot of attention from investigators in the context of cell-based therapies of several human diseases. Despite the fact that bone marrow represents the main available source of MSCs, the use of bone marrow-derived cells is not always acceptable due to the high degree of viral infection and the significant drop in cell number and proliferative/differentiation capacity with age. Thus, the search for possible alternative MSC sources remains to be validated. Umbilical cord blood is a rich source of hematopoietic stem/progenitor cells and does not contain mesenchymal progenitors. However, MSCs circulate in the blood of preterm fetuses and may be successfully isolated and expanded. Where these cells home at the end of gestation is not clear. In this investigation, we have made an attempt to isolate MSCs from the subendothelial layer of umbilical cord vein using two standard methodological approaches: the routine isolation of human umbilical vein endothelial cell protocol and culture of isolated cells under conditions appropriate for bone-marrow-derived MSCs. Our results suggest that cord vasculature contains a high number of MSC-like elements forming colonies of fibroblastoid cells that may be successfully expanded in culture. These MSC-like cells contain no endothelium- or leukocyte-specific antigens but express alpha-smooth muscle actin and several mesenchymal cell markers. Therefore, umbilical cord/placenta stroma could be regarded as an alternative source of MSCs for experimental and clinical needs.
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Mesoderma/citologia , Células-Tronco , Cordão Umbilical/citologia , Endotélio Vascular/citologia , Idade Gestacional , Humanos , Recém-Nascido , Células-Tronco/química , Veias Umbilicais/citologiaRESUMO
BACKGROUND: Secretion of recombinant proteins in yeast can be affected by their improper folding in the endoplasmic reticulum and subsequent elimination of the misfolded molecules via the endoplasmic reticulum associated protein degradation pathway. Recombinant proteins can also be degraded by the vacuolar protease complex. Human urokinase type plasminogen activator (uPA) is poorly secreted by yeast but the mechanisms interfering with its secretion are largely unknown. RESULTS: We show that in Hansenula polymorpha overexpression worsens uPA secretion and stimulates its intracellular aggregation. The absence of the Golgi modifications in accumulated uPA suggests that aggregation occurs within the endoplasmic reticulum. Deletion analysis has shown that the N-terminal domains were responsible for poor uPA secretion and propensity to aggregate. Mutation abolishing N-glycosylation decreased the efficiency of uPA secretion and increased its aggregation degree. Retention of uPA in the endoplasmic reticulum stimulates its aggregation. CONCLUSIONS: The data obtained demonstrate that defect of uPA secretion in yeast is related to its retention in the endoplasmic reticulum. Accumulation of uPA within the endoplasmic reticulum disturbs its proper folding and leads to formation of high molecular weight aggregates.
RESUMO
The Sup35 (eRF3) translation termination factor of Saccharomyces cerevisiae can undergo a prion-like conformational conversion, thus resulting in the [PSI(+)] nonsense-suppressor determinant. In vivo this process depends critically on the chaperone Hsp104, whose lack or overexpression can cure [PSI(+)]. The use of artificial prion [PSI(+)PS] based on a hybrid Sup35PS with prion domain from the yeast Pichia methanolica allowed us to uncover three more chaperones, Ssb1, Ssa1, and Ydj1, whose overexpression can cure prion determinants. Here, we used the [PSI(+)PS] to search a multicopy yeast genomic library for novel factors able to cure prions. It was found that overexpression of the Hsp40 family chaperones Sis1 and Ynl077w, chaperone Sti1, transcriptional factors Sfl1 and Ssn8, and acidic ribosomal protein Rpp0 can interfere with propagation and manifestation of [PSI(+)PS] in a prion strain-specific manner. Some of these factors also affected the manifestation and propagation of conventional [PSI(+)]. Excess of Sfl1, Ssn8, and Rpp0 influenced at least one of the tested chaperone-specific promoters, SSA4, HSP104, and model promoters, with either the heat shock or stress response elements. Thus, the induction of chaperone expression by these proteins could explain their prion-curing effects.