Detecting Dementia from Face-Related Features with Automated Computational Methods

Alzheimer's disease (AD) is a type of dementia that is more likely to occur as people age. It currently has no known cure. As the world's population is aging quickly, early screening for AD has become increasingly important. Traditional screening methods such as brain scans or psychiatric tests are stressful and costly. The patients are likely to feel reluctant to such screenings and fail to receive timely intervention. While researchers have been exploring the use of language in dementia detection, less attention has been given to face-related features. The paper focuses on investigating how face-related features can aid in detecting dementia by exploring the PROMPT dataset that contains video data collected from patients with dementia during interviews. In this work, we extracted three types of features from the videos, including face mesh, Histogram of Oriented Gradients (HOG) features, and Action Units (AU). We trained traditional machine learning models and deep learning models on the extracted features and investigated their effectiveness in dementia detection. Our experiments show that the use of HOG features achieved the highest accuracy of 79% in dementia detection, followed by AU features with 71% accuracy, and face mesh features with 66% accuracy. Our results show that face-related features have the potential to be a crucial indicator in automated computational dementia detection.

Modification of the therapist's facial expressions using virtual reality technology during the treatment of social anxiety disorder: a case series

Exposure therapy is a mainstream of treatment for social anxiety disorder (SAD). However, effort and time are required to recreate interpersonal situations that produce moderate anxiety. On the other hand, virtual reality exposure therapy can easily control anxiety-inducing conditions and allow for graduated exposure. However, artificial intelligence and animations that speak as naturally as actual humans are not yet practical, adding to the limitations of these treatments. The authors propose the use of a virtual reality technology that can transform facial expressions into smiling or sad faces in real time and display them on a monitor, potentially solving the above-mentioned problems associated with virtual reality animations. This feasibility study was conducted to determine whether this system can be safely applied to the treatment of SAD patients. A total of four SAD patients received 16 exposure therapy sessions led by an experienced therapist over a monitor; throughout the sessions, the facial expressions of the therapist were modified using software to display expressions ranging from smiling to sad on the monitor that was being viewed by the patient. Client satisfaction, treatment alliance, and symptom assessments were then conducted. Although one patient dropped out of the study, treatment satisfaction and treatment alliance were scored high in all the cases. In two of the four cases, the improvement in symptoms was sustained over time. Exposure therapy in which the interviewer's facial expressions are modified to induce appropriate levels of anxiety in the patient can be safely used for the treatment of SAD patients and may be effective for some patients.

Language patterns in Japanese patients with Alzheimer disease: A machine learning approach

AIM

The authors applied natural language processing and machine learning to explore the disease-related language patterns that warrant objective measures for assessing language ability in Japanese patients with Alzheimer disease (AD), while most previous studies have used large publicly available data sets in Euro-American languages.

METHODS

The authors obtained 276 speech samples from 42 patients with AD and 52 healthy controls, aged 50 years or older. A natural language processing library for Python was used, spaCy, with an add-on library, GiNZA, which is a Japanese parser based on Universal Dependencies designed to facilitate multilingual parser development. The authors used eXtreme Gradient Boosting for our classification algorithm. Each unit of part-of-speech and dependency was tagged and counted to create features such as tag-frequency and tag-to-tag transition-frequency. Each feature's importance was computed during the 100-fold repeated random subsampling validation and averaged.

RESULTS

The model resulted in an accuracy of 0.84 (SD = 0.06), and an area under the curve of 0.90 (SD = 0.03). Among the features that were important for such predictions, seven of the top 10 features were related to part-of-speech, while the remaining three were related to dependency. A box plot analysis demonstrated that the appearance rates of content words-related features were lower among the patients, whereas those with stagnation-related features were higher.

CONCLUSION

The current study demonstrated a promising level of accuracy for predicting AD and found the language patterns corresponding to the type of lexical-semantic decline known as 'empty speech', which is regarded as a characteristic of AD.

Understanding psychiatric illness through natural language processing (UNDERPIN): Rationale, design, and methodology

Introduction

Psychiatric disorders are diagnosed through observations of psychiatrists according to diagnostic criteria such as the DSM-5. Such observations, however, are mainly based on each psychiatrist's level of experience and often lack objectivity, potentially leading to disagreements among psychiatrists. In contrast, specific linguistic features can be observed in some psychiatric disorders, such as a loosening of associations in schizophrenia. Some studies explored biomarkers, but biomarkers have yet to be used in clinical practice.

Aim

The purposes of this study are to create a large dataset of Japanese speech data labeled with detailed information on psychiatric disorders and neurocognitive disorders to quantify the linguistic features of those disorders using natural language processing and, finally, to develop objective and easy-to-use biomarkers for diagnosing and assessing the severity of them.

Methods

This study will have a multi-center prospective design. The DSM-5 or ICD-11 criteria for major depressive disorder, bipolar disorder, schizophrenia, and anxiety disorder and for major and minor neurocognitive disorders will be regarded as the inclusion criteria for the psychiatric disorder samples. For the healthy subjects, the absence of a history of psychiatric disorders will be confirmed using the Mini-International Neuropsychiatric Interview (M.I.N.I.). The absence of current cognitive decline will be confirmed using the Mini-Mental State Examination (MMSE). A psychiatrist or psychologist will conduct 30-to-60-min interviews with each participant; these interviews will include free conversation, picture-description task, and story-telling task, all of which will be recorded using a microphone headset. In addition, the severity of disorders will be assessed using clinical rating scales. Data will be collected from each participant at least twice during the study period and up to a maximum of five times at an interval of at least one month.

Discussion

This study is unique in its large sample size and the novelty of its method, and has potential for applications in many fields. We have some challenges regarding inter-rater reliability and the linguistic peculiarities of Japanese. As of September 2022, we have collected a total of >1000 records from >400 participants. To the best of our knowledge, this data sample is one of the largest in this field.

Clinical Trial Registration

Identifier: UMIN000032141.

Development of medical device software for the screening and assessment of depression severity using data collected from a wristband-type wearable device: SWIFT study protocol

INTRODUCTION

Few biomarkers can be used clinically to diagnose and assess the severity of depression. However, a decrease in activity and sleep efficiency can be observed in depressed patients, and recent technological developments have made it possible to measure these changes. In addition, physiological changes, such as heart rate variability, can be used to distinguish depressed patients from normal persons; these parameters can be used to improve diagnostic accuracy. The proposed research will explore and construct machine learning models capable of detecting depressive episodes and assessing their severity using data collected from wristband-type wearable devices.

METHODS AND ANALYSIS

Patients with depressive symptoms and healthy subjects will wear a wristband-type wearable device for 7 days; data on triaxial acceleration, pulse rate, skin temperature, and ultraviolet light will be collected. On the seventh day of wearing, the severity of depressive episodes will be assessed using Structured Clinical Interview for DSM-5 (SCID-5), Hamilton Depression Rating Scale (HAMD), and other scales. Data for up to five 7-day periods of device wearing will be collected from each subject. Using wearable device data associated with clinical symptoms as supervisory data, we will explore and build a machine learning model capable of identifying the presence or absence of depressive episodes and predicting the HAMD scores for an unknown data set.

DISCUSSION

Our machine learning model could improve the clinical diagnosis and management of depression through the use of a wearable medical device.

CLINICAL TRIAL REGISTRATION

[https://jrct.niph.go.jp/latest-detail/jRCT1031210478], identifier [jRCT1031210478].

Virtual reality exposure therapy for social anxiety disorder: a systematic review and meta-analysis

BACKGROUND

Virtual reality exposure therapy (VRET) is currently being used to treat social anxiety disorder (SAD); however, VRET's magnitude of efficacy, duration of efficacy, and impact on treatment discontinuation are still unclear.

METHODS

We conducted a meta-analysis of studies that investigated the efficacy of VRET for SAD. The search strategy and analysis method are registered at PROSPERO (#CRD42019121097). Inclusion criteria were: (1) studies that targeted patients with SAD or related phobias; (2) studies where VRET was conducted for at least three sessions; (3) studies that included at least 10 participants. The primary outcome was social anxiety evaluation score change. Hedges' g and its 95% confidence intervals were calculated using random-effect models. The secondary outcome was the risk ratio for treatment discontinuation.

RESULTS

Twenty-two studies (n = 703) met the inclusion criteria and were analyzed. The efficacy of VRET for SAD was significant and continued over a long-term follow-up period: Hedges' g for effect size at post-intervention, -0.86 (-1.04 to -0.68); three months post-intervention, -1.03 (-1.35 to -0.72); 6 months post-intervention, -1.14 (-1.39 to -0.89); and 12 months post-intervention, -0.74 (-1.05 to -0.43). When compared to in vivo exposure, the efficacy of VRET was similar at post-intervention but became inferior at later follow-up points. Participant dropout rates showed no significant difference compared to in vivo exposure.

CONCLUSION

VRET is an acceptable treatment for SAD patients that has significant, long-lasting efficacy, although it is possible that during long-term follow-up, VRET efficacy lessens as compared to in vivo exposure.

Evaluating the severity of depressive symptoms using upper body motion captured by RGB-depth sensors and machine learning in a clinical interview setting: A preliminary study

BACKGROUND

Mood disorders have long been known to affect motor function. While methods to objectively assess such symptoms have been used in experiments, those same methods have not yet been applied in clinical practice because the methods are time-consuming, labor-intensive, or invasive.

METHODS

We videotaped the upper body of each subject using a Red-Green-Blue-Depth (RGB-D) sensor during a clinical interview setting. We then examined the relationship between depressive symptoms and body motion by comparing the head motion of patients with major depressive disorders (MDD) and bipolar disorders (BD) to the motion of healthy controls (HC). Furthermore, we attempted to predict the severity of depressive symptoms by using machine learning.

RESULTS

A total of 47 participants (HC, n = 16; MDD, n = 17; BD, n = 14) participated in the study, contributing to 144 data sets. It was found that patients with depression move significantly slower compared to HC in the 5th percentile and 50th percentile of motion speed. In addition, Hamilton Depression Rating Scale (HAMD)-17 scores correlated with 5th percentile, 50th percentile, and mean speed of motion. Moreover, using machine learning, the presence and/or severity of depressive symptoms based on HAMD-17 scores were distinguished by a kappa coefficient of 0.37 to 0.43.

LIMITATIONS

Limitations include the small number of subjects, especially the number of severe cases and young people.

CONCLUSIONS

The RGB-D sensor captured some differences in upper body motion between depressed patients and controls. If much larger samples are accumulated, machine learning may be useful in identifying objective measures for depression in the future.

Evaluating depression with multimodal wristband-type wearable device: screening and assessing patient severity utilizing machine-learning

OBJECTIVE

We aimed to develop a machine learning algorithm to screen for depression and assess severity based on data from wearable devices.

METHODS

We used a wearable device that calculates steps, energy expenditure, body movement, sleep time, heart rate, skin temperature, and ultraviolet light exposure. Depressed patients and healthy volunteers wore the device continuously for the study period. The modalities were compared hourly between patients and healthy volunteers. XGBoost was used to build machine learning models and 10-fold cross-validation was applied for the validation.

RESULTS

Forty-five depressed patients and 41 healthy controls participated, creating a combined 5,250 days' worth of data. Heart rate, steps, and sleep were significantly different between patients and healthy volunteers in some comparisons. Similar differences were also observed longitudinally when patients' symptoms improved. Based on seven days' data, the model identified symptomatic patients with 0.76 accuracy and predicted Hamilton Depression Rating Scale-17 scores with a 0.61 correlation coefficient. Skin temperature, sleep time-related features, and the correlation of those modalities were the most significant features in machine learning.

LIMITATIONS

The small number of subjects who participated in this study may have weakened the statistical significance of the study. There are differences in the demographic data among groups although we performed a correction for multiple comparisons. Validation in independent datasets was not performed, although 10-fold cross validation with the internal data was conducted.

CONCLUSION

The results indicated that utilizing wearable devices and machine learning may be useful in identifying depression as well as assessing severity.

Primary biliary cirrhosis and autoantibodies

Fifty years have passed since anti-mitochondrial antibodies were found in patients with primary biliary cirrhosis (PBC). PBC is an autoimmune hepatic disease in which 85-90% of patient antibodies bind to mitochondrial antigens that include pyruvate dehydrogenase complex (PDC)-E2 and other members of the oxaloacid dehydrogenase family. In addition, indirect immunofluorescence (IIF) assays utilizing HEp-2 cell substrates have been used to identify anti-centromere antibodies in 20-30% of PBC sera. These antibodies are generally easily recognized, however, anti-nuclear envelope and anti-multiple nuclear dot antibodies are occasionally more difficult to recognize with certainty by IIF. The use of enzyme linked immunosorbent assays that utilize recombinant gp210 (an autoantigen of the nuclear envelope) and/or sp100 (a protein target represented by multiple nuclear dots) should be particularly considered in anti-mitochondrial antibody negative PBC sera. Although the clinical significance of these antibodies still remains to be determined, there is evidence that the existence of anti-gp210 antibodies are related to poorer prognosis and more aggressive disease progression.

Anti-p97/VCP antibodies: an autoantibody marker for a subset of primary biliary cirrhosis patients with milder disease?

We previously reported that 12.5% of primary biliary cirrhosis (PBC) sera reacted with a 95 kDa cytosol protein (p95c) that was subsequently identified as a p97/valosin-containing protein (VCP). The clinical features and course of the six anti-p97/VCP-positive PBC patients with Scheuer's stage 1 and 2 liver biopsies were monitored for an average of 15 years. This group was compared with 50 PBC patients that did not have detectable anti-VCP. Autoantibodies to a full-length recombinant p97/VCP were assayed by immunoprecipitation. All six PBC patients with anti-VCP had antibodies to the mitochondrial pyruvate dehydrogenase complex-E2 antigen as measured by an addressable laser bead immunoassay. The first was a male with no evidence of liver failure that died of cerebral infarction at the age of 85. The second was a 73-year-old female with Hashimoto's thyroiditis who has remained clinically stable without ursodeoxycolic acid (UDCA) treatment. Although the third had no HCV antibodies, he developed hepatocellular carcinoma at the age of 76 and died of renal failure at 78. The fourth was a 50-year-old female who remained clinically stable during follow-up and the fifth with Hashimoto's thyroiditis and stable liver function following UCDA treatment. The sixth was a male patient presenting a mild clinical course. The clinical course of these patients was in contrast to the 50 comparison group PBC patients who did not have anti-p97/VCP. As the six PBC patients with anti-p97/VCP antibodies had slowly progressive liver disease and no mortality related to autoimmune liver disease, our observations suggest that this autoantibody might be an indicator of a favourable prognosis.

Autoantibodies from primary biliary cirrhosis patients with anti-p95c antibodies bind to recombinant p97/VCP and inhibit in vitro nuclear envelope assembly

We have reported previously that p95c, a novel 95-kDa cytosolic protein, was the target of autoantibodies in sera of patients with autoimmune hepatic diseases. We studied 30 sera that were shown previously to immunoprecipitate a 95 kDa protein from [(35)S]-methionine-labelled HeLa lysates and had a specific precipitin band in immunodiffusion. Thirteen sera were available to test the ability of p95c antibodies to inhibit nuclear envelope assembly in an in vitro assay in which confocal fluorescence microscopy was also used to identify the stages at which nuclear assembly was inhibited. The percentage inhibition of nuclear envelope assembly of the 13 sera ranged from 7% to 99% and nuclear envelope assembly and the swelling of nucleus was inhibited at several stages. The percentage inhibition of nuclear assembly was correlated with the titre of anti-p95c as determined by immunodiffusion. To confirm the identity of this autoantigen, we used a full-length cDNA of the p97/valosin-containing protein (VCP) to produce a radiolabelled recombinant protein that was then used in an immunoprecipitation (IP) assay. Our study demonstrated that 12 of the 13 (93%) human sera with antibodies to p95c immunoprecipitated recombinant p97/VCP. Because p95c and p97 have similar molecular masses and cell localization, and because the majority of sera bind recombinant p97/VCP and anti-p95c antibodies inhibit nuclear assembly, this is compelling evidence that p95c and p97/VCP are identical.

Autoantigens of the nuclear pore complex

The nuclear envelope (NE) is one of many intracellular targets of the autoimmune response in patients with autoimmune liver disease, systemic lupus erythematosus, and related conditions. In eukaryotic organisms the NE consists of five interconnected regions: an outer nuclear membrane (ONM) that is continuous with the endoplasmic reticulum, an intermembrane or perinuclear space, an inner nuclear membrane (INM) with a unique set of integral membrane proteins, the underlying nuclear lamina, and the pore domains that are regions where the ONM and INM come together. The pore domains are sites of regulated continuity between the cytoplasm and nucleus that are occupied by supramolecular structures, termed nuclear pore complexes (NPCs). Human autoantibodies identified to date bind to specific components in three of the five NE compartments. Autoantigen targets include the lamins A, B, and C of the nuclear lamina, gp210, p62 complex proteins, Nup153, and Tpr within the NPC, and LBR, MAN1, LAP1, and LAP2 that are integral proteins of the INM. Autoantibodies to these NE targets have been shown to be correlated with various autoimmune diseases such as primary biliary cirrhosis, other autoimmune liver diseases and systemic rheumatic diseases. Now that the proteome of the NE is more clearly defined, other autoantibodies to components in this cell compartment are likely to be defined.

A male patient who developed late-onset primary biliary cirrhosis presenting with antinuclear envelope antibodies

Abstract An 81-year-old man who had previously shown high levels of alkaline phosphatase (ALP), γ-glutamyltransferase (GTP), and total bilirubin presented with acute liver damage. He was positive for serum anti-gp210 and anti-p62 antibodies, but negative for serum antimitochondrial antibody. A liver biopsy revealed massive interstitial fibrosis and pseudolobulus, which were compatible with a diagnosis of primary biliary cirrhosis (PBC) at Scheuer's stage 4. He was given ursodeoxycolic acid at 600 mg/day. However, his condition deteriorated, and he eventually died of hepatic insufficiency in a state of malnutrition. We hypothesize that the presence of anti-gp210 and anti-p62 complex protein antibodies, rather than that of antimitochondrial antibodies, was correlated with the progression of PBC in this particular case.

Signal processing and a groove baseband recording method to achieve a high-density optical disc

We propose a method for recording a multilevel signal onto optical read-only-memory discs. In this method we use signal processing to generate a multilevel recording signal that satisfies the zero-intersymbol interference condition and the zero-dc condition. The resultant multilevel signal is emboss recorded as the position displacement of groove walls. To play back a disc, push-pull detection and an adaptive equalizer are used. We also introduce feedback to reduce the nonlinear characteristics existing in the recording and playback systems. An experimental disc with 0.6-mum track pitch and 0.28-mum/bit density is made. When a digital versatile disc equivalent optical pickup is used to play back this disc, we confirm that a two-dimensional eye pattern of 16 levels is clearly observed.

N-ethylmaleimide-sensitive factor is associated with the nuclear envelope

N-Ethylmaleimide-sensitive factor (NSF) is an ATPase involved in many membrane fusion events within the exocytic and endocytotic pathways. In the present study we showed that NSF is associated with the nuclear envelope. Golgi-associated NSF was released from membranes upon incubation with Mg(2+)-ATP, reflecting the disassembly of a complex consisting of NSF, soluble NSF attachment proteins (SNAPs), and SNAP receptors (SNAREs). In contrast nuclear envelope-associated NSF in interphase cells was not released by the same treatment. During mitosis, however, it was released from nuclear membranes by Mg(2+)-ATP. These results suggest that the binding mode of nuclear membrane-associated NSF changes during the cell cycle.

The Saccharomyces cerevisiae RuvB-like protein, Tih2p, is required for cell cycle progression and RNA polymerase II-directed transcription

Two highly conserved RuvB-like putative DNA helicases, p47/TIP49b and p50/TIP49a, have been identified in the eukaryotes. Here, we study the function of Saccharomyces cerevisiae TIH2, which corresponds to mammalian p47/TIP49b. Tih2p is required for vegetative cell growth and localizes in the nucleus. Immunoprecipitation analysis revealed that Tih2p tightly interacts with Tih1p, the counterpart of mammalian p50/TIP49a, which has been shown to interact with the TATA-binding protein and the RNA polymerase II holoenzyme complex. Furthermore, the mutational study of the Walker A motif, which is required for nucleotide binding and hydrolysis, showed that this motif plays indispensable roles in the function of Tih2p. When a temperature-sensitive tih2 mutant, tih2-160, was incubated at the nonpermissive temperature, cells were rapidly arrested in the G(1) phase. Northern blot analysis revealed that Tih2p is required for transcription of G(1) cyclin and of several ribosomal protein genes. The similarities between the mutant phenotypes of tih2-160 and those of taf145 mutants suggest a role for TIH2 in the regulation of RNA polymerase II-directed transcription.

Relevance of IgG receptor IIIb (CD16) polymorphism to handling of Porphyromonas gingivalis: implications for the pathogenesis of adult periodontitis

Polymorphonuclear neutrophils (PMNs) are essential in host defense against periodontopathic bacteria such as Porphyromonas gingivalis. The uptake of immunoglobulin G (IgG)-opsonized bacteria via IgG Fc receptors (Fc gamma R) on PMN constitutes a central defense mechanism in periodontium. Fc gamma RIIIb is the most abundantly expressed Fc gamma R on PMN and is functionally polymorphic. The Fc gamma RIIIb-NA1 and IIIb-NA2 allotypes interact differently with IgG1- and IgG3-opsonized particles. We recently showed recurrence rates of adult periodontitis (AP) to be higher in patients carrying at least 1 Fc gamma RIIIb-NA2 allele. In this study we evaluated the functional relevance of the Fc gamma RIIIb polymorphism to anti-P. gingivalis PMN effector functions. Our results showed Fc gamma RIIIb-NA2-carrying PMN from both patients with AP and healthy controls to be less efficient in phagocytosis and induction of oxidative burst upon interaction with IgG1- and IgG3-opsonized P. gingivalis. These functional differences between Fc gamma RIIIb-NA1 and IIIb-NA2 were observed in the presence of CD32-blocking antibody fragments, but not upon blocking CD16. Moreover, PMNs from AP patients exhibited increased Fc gamma RIIIb-allelic differences in IgG3-induced oxidative burst compared to control PMNs. These results support the concept that Fc gamma RIIIb heterogeneity may influence the clinical course of AP.

Molecular cloning and splicing isoforms of mouse p144, a homologue of CA150

We previously characterized p144 bearing N-acetylglucosamine residues in a rat liver nuclear matrix fraction. Based on partial amino acid sequences of rat p144, mouse p144 cDNA was cloned and sequenced, and its amino acid sequence was predicted. The sequence revealed that p144 is a rat homologue of CA150, which is a transcription factor involved in Tat-activated human immunodeficiency virus type 1 transcription. The reported human CA150 consists of 1098 amino acids and has a leucine zipper-like motif in its carboxyl-region. However, a clone of mouse p144 cDNA encoded a CA150 consisting of 1,034 amino acids. The mouse CA150 was shorter by 64 amino acids than hitherto known human CA150 and lacked the leucine zipper-like motif. We designated the longer and shorter CA150 species as CA150a and CA150b, respectively. The partial nucleotide sequences of other mouse p144 cDNA clones were examined and it was found that some clones encode CA150a having a leucine zipper-like motif. It was suggested that CA150a and CA150b are splicing isoforms. All rat and mouse tissues examined contained transcripts for both CA150a and CA150b. Both transcripts were detected in human blood and Jurkat cells as well as mouse CD4(+) T-cells, which are the HIV-1-sensitive counterpart in humans.

Stimulus-coupled interaction of tyrosine hydroxylase with 14-3-3 proteins

Tyrosine hydroxylase (TH) is phosphorylated by CaM kinase II and is activated in situ in response to a variety of stimuli that increase intracellular Ca(2+). We report here, using baculovirus-expressed TH, that the 14-3-3 protein binds and activates the expressed TH when the enzyme is phosphorylated at Ser-19, a site of CaM kinase II-dependent phosphorylation located in the regulatory domain of TH. Site-directed mutagenesis showed that a TH mutant in which Ser-19 was substituted by Ala retained enzymatic activity at the same level as the non-mutated enzyme, but was a poor substrate for CaM kinase II and did not bind the 14-3-3 protein. Likewise, a synthetic phosphopeptide (FRRAVpSELDA) corresponding to the part of the TH sequence, including phosphoSer-19, inhibited the interaction between the expressed TH and 14-3-3, while the phosphopeptide (GRRQpSLIED) corresponding to the site of cAMP-dependent phosphorylation (Ser-40) had little effect on complex formation. The complex was very stable with a dissociation constant of 3 nM. Furthermore, analysis of PC12nnr5 cells transfected with myc-tagged 14-3-3 showed that 14-3-3 formed a complex with endogenous TH when the cultured cells were exposed to a high K(+) concentration that increases intracellular Ca(2+) and phosphorylation of Ser-19 in TH. These findings suggest that the 14-3-3 protein participates in the stimulus-coupled regulation of catecholamine synthesis that occurs in response to depolarization-evoked, Ca(2+)-dependent phosphorylation of TH.

In vitro nuclear assembly with affinity-purified nuclear envelope precursor vesicle fractions, PV1 and PV2

Nuclear envelope precursor vesicles were affinity purified from a Xenopus egg extract by a chromatin binding method. Vesicles bound to chromatin at 4 degrees C were dissociated with a high salt buffer and further fractionated into nuclear envelope precursor vesicle fractions 1 (PV1) and 2 (PV2) by differential centrifugation. PV1 contained larger vesicles. When chromatin was incubated in a Xenopus egg cytosol fraction supplemented with PV1, vesicles bound to chromatin, fused with each other, formed a bilayered nuclear envelope, and assembled into spherical small nuclei. However, the thus assembled nuclei did not grow to the normal size. Nuclear pore complexes were not found on the thus assembled nuclei. On the other hand, PV2 contained smaller vesicles. PV2 vesicles bound to chromatin, fused little with each other in the Xenopus egg cytosol fraction, and no nuclei were assembled. When PV1 supplemented with PV2 was used for the nuclear assembly reaction, the assembled nuclei grew to the normal size. Nuclear pore complexes existed in the thus assembled nuclear envelopes. These results suggested that 1) two vesicle populations, PV1 and PV2, are necessary for the assembly of normal sized nuclei, 2) PV1 contains a chromatin targeting molecule(s) and membrane fusion machinery, 3) PV2 contains a chromatin targeting molecule(s) and a molecule(s) necessary for nuclear pore complex assembly, and 4) PV1 has the ability to assemble a nuclear membrane, and PV2 is necessary for the assembly of nuclear pore complexes and for nuclei to grow to the normal size. An in vitro nuclear assembly system constituted with affinity-purified vesicle fractions, PV1 and PV2, was established.

Relevance of Fc gamma RIIIa-158V-F polymorphism to recurrence of adult periodontitis in Japanese patients

The immunoglobulin receptor Fc gamma RIIIa (CD16) is distributed on natural killer (NK) cells, macrophages, and gamma delta T cells, and is polymorphic. Fc gamma RIIIa-158V has a higher affinity for both monomeric and immune complexed IgG1, IgG3, and IgG4 than IIIa-158F. We determined Fc gamma RIIIa-158V/F genotypes of Japanese patients with adult periodontitis. A significant over-representation of Fc gamma RIIIa-158F was found in patients with recurrence, compared with patients without recurrence, making Fc gamma RIIIA a candidate gene for recurrence risk of adult periodontitis.

Molecular cloning of mouse p47, a second group mammalian RuvB DNA helicase-like protein: homology with those from human and Saccharomyces cerevisiae

A 47k protein (p47) in a high-salt buffer extract of a rat liver nuclear matrix fraction was purified by means of a wheat germ agglutinin affinity column, reversed phase HPLC, and SDS-PAGE, and partial amino acid sequences were analyzed. Based on these sequences, the mouse cDNA of the protein was cloned and sequenced, and its amino acid sequence was deduced. Mouse p47 consists of 463 amino acid residues with a molecular weight of 51,112. The amino acid sequences of human and Saccharomyces cerevisiae p47s were also deduced from the nucleotide sequences of "expressed sequence tag" fragments and genomic DNA, respectively. These sequences contain helicase motifs and show homology to bacterial RuvB DNA helicases acting in homologous recombination. They also show homology with the putative mammalian helicases p50/TIP49 and RUVBL1. Comparison of the amino acid sequences of p47 group proteins and those of p50/TIP49 group proteins revealed the p47 group proteins to comprise a group distinct from the p50/TIP49 proteins. Ultracentrifugation and gel filtration analyses showed that p47 in the rat liver cytosol fraction exists as large complexes of 697k.

Molecular shape and ATP binding activity of rat p50, a putative mammalian homologue of RuvB DNA helicase

Based on partial amino acid sequences of p50 purified from a high-salt buffer extract of a rat liver nuclear matrix fraction, p50 cDNA was cloned and sequenced, and its amino acid sequence was predicted. The sequence contained helicase motifs, and showed homology with RuvB DNA helicase of Thermus thermophilus and an open reading frame for an unknown 50.5 k protein of Saccharomyces cerevisiae. p50 was expressed as a GST-fusion protein and antiserum against the protein was generated. p50 was localized to the nuclear matrix by cell fractionation and immunoblotting. p50 bound to ATP-Sepharose beads. Ultracentrifugation and gel filtration analyses showed that p50 in rat liver and Xenopus egg mitotic extracts exists as large complexes corresponding to 697 k and 447 k, respectively. A 50 k protein reactive with p50 antibodies was detected not only in rat liver nuclei, but also in a Xenopus egg cytoplasm fraction and a S. cerevisiae extract. This suggests that this putative DNA helicase is present in a wide variety of species ranging from yeast to mammals.

Construction and performance test of SGM-TRAIN at UVSOR

A new spherical-grating monochromator with translational and rotational assembly including a normal-incidence mount (SGM-TRAIN) has been constructed at BL5A of the UVSOR facility. The SGM-TRAIN is an advanced version of a constant-length SGM with the following improvements: (i) a wide energy range of 5-250 eV; (ii) a high resolving power; (iii) use of linear and circular polarization; (iv) reduction of second-order light; (v) two computer-controlled driving modes. Part of the performance tests are reported along with a detailed description of the design.

Characterization of the binding of nuclear envelope precursor vesicles and chromatin, and purification of the vesicles

The binding of nuclear envelope precursor vesicles and chromatin was characterized by using an in vitro system constituted from a Xenopus egg extract and demembranated Xenopus sperm chromatin. The results of binding studies in the presence of salts, urea, and a chelator showed that the binding involves an ionic interaction. Chemical modification studies suggested that a protein(s) in the vesicles, which is responsible for the binding with chromatin, has essential lysine, histidine, and methionine residues. The vesicle protein could not be extracted from vesicles with 1 M KCl, 2 M urea, or 0.1 M Na2CO3, suggesting that it is an intrinsic membrane protein. The protein was denatured with 8 M urea and 0.1 M Na2CO3, and could be renatured by incubation at 23 degrees C, suggesting that the native conformation of the protein is important for the binding. Affinity purification of nuclear envelope precursor vesicles was achieved by binding to chromatin and dissociation with 0.24 M NaCl. The vesicle fraction thus obtained exhibited the ability to form nuclear envelope on incubation with chromatin in Xenopus egg cytosol without any other membrane fraction. These results suggested that there is a nuclear envelope precursor vesicle population containing both a chromatin targeting protein and vesicle fusion machinery.

Methylmercury alters the tyrosination status of tubulin in the brains of acutely intoxicated rats

Tyrosination/detyrosination, a post-translational modification at the carboxyl terminus of alpha-tubulin, was investigated in the brain cytosol fraction of rats treated with methylmercury (MeHg) chloride (10 mg/kg per day, for 7 days). The amount of detyrosinated tubulin species, determined as the incorporation of 14C-tyrosine at the carboxyl-terminal end of alpha-tubulin, was significantly decreased throughout the experimental period of MeHg intoxication. Furthermore, the activity of tubulin-tyrosine ligase, as well as the amounts of tyrosinatable tubulin determined and calculated by a method involving pancreatic carboxypeptidase A, also decreased in the latent and symptomatic periods. Tubulin-tyrosine carboxypeptidase activity did not change during the MeHg intoxication. The total amounts of alpha- and beta-tubulins, as determined by densitometry and immunoblotting, did not show significant changes during the intoxication. These results suggest that MeHg treatment may produce perturbation of cellular activities associated with the tubulin/microtubule system by altering the tyrosination status of tubulin in the rat brain.

The 14-3-3 protein binds its target proteins with a common site located towards the C-terminus

The 14-3-3 protein family binds a variety of proteins in cell-signaling pathways, but the structural elements necessary for the ligand binding are poorly understood. Here we demonstrate that the 'box-1' region, which spans residues 171-213 in the eta-isoform and was previously identified as the binding site of 14-3-3 to the phosphorylated tryptophan hydroxylase, plays a critical role in the interaction with many target proteins. Using a series of truncated 14-3-3 mutants, we show that the mutant 167-213 carrying box-1 binds bacurovirus-expressed Raf-1 and Bcr protein kinases to the similar extent as the full-length 14-3-3 in a phosphorylation-dependent manner, while the mutants lacking this region abolish the binding activity. Furthermore, the box-1 region also appears essential for binding of 14-3-3 to more than 40 phosphoproteins found in the brainstem extract. These results suggest that the box-1 region, consisting of helices 7 and 8 in the tertiary structure, is a common structural element whereby the 14-3-3 protein binds many, if not all, target proteins.

cDNA cloning of nuclear localization signal binding protein NBP60, a rat homologue of lamin B receptor, and identification of binding sites of human lamin B receptor for nuclear localization signals and chromatin

We previously purified and characterized a nuclear localization signal (NLS) binding protein, NBP60, in rat liver nuclear envelopes. In this study, we cloned and sequenced the cDNA of rat NBP60, and predicted an amino acid sequence comprising 620 amino acids. The sequence revealed that NBP60 is a rat homologue of lamin B receptor (LBR), and is 79 and 63% identical in amino acids to human and chicken LBR, respectively. Using three fusion proteins containing different parts of the amino-terminal domain of human LBR, it was shown that the stretch comprising amino acids 1 to 89, which contains a Ser-Arg rich region (RS region), binds to nucleoplasmin and that the binding was inhibited by a common NLS-peptide. These results suggested that the amino-terminal domain of LBR contains an NLS-binding site. Furthermore, it was shown that the stretch comprising amino acids 1 to 53, which does not contain the RS region or the predicted DNA-binding site, binds to Xenopus laevis sperm chromatin.

Characterization of p92, karyopherin beta, co-purified with N-acetylglucosamine-bearing nucleoporins from rat liver nuclear envelopes

A 92k protein (p92) was purified from the wheat germ agglutinin-Sepharose (WGA-Sepharose) bound fraction of a rat liver nuclear envelope salt-extract by DEAE-5PW and hydroxyapatite HPLCs. Partial amino acid sequence analysis of p92 revealed that it is karyopherin beta, which was found recently in the cytosolic fraction. It was shown using anti-p92 antiserum that the protein is present in the nuclear envelope and cytosolic fractions, in almost the same amounts, but not in other subcellular fractions of rat liver. p92 bound to N-acetylglucosamine bearing nucleoporins (GNPs) on WGA-Sepharose, but not directly to WGA. The amount of p92 found in the rat liver nuclear envelope fraction corresponded to about 10% of the nuclear pore complex in mass, and to as much as 140 mol of p92 per mol of nuclear pore complex. Hydrodynamic analysis of the purified p92 suggested that the molecule is present as a monomer and that it is a rod-shaped molecule. The interaction of p92 and GNPs seemed to be hydrophobic and ionic. Based on these results, the participation of nuclear envelope p92 in protein nuclear transport is discussed.

Subcellular distribution and phosphorylation of the nuclear localization signal binding protein, NBP60

We previously purified a nuclear localization signal binding protein, NBP60, from rat liver (1993, J. Biochem. 113, 308-313). In this study, the subcellular localization of NBP60 was examined using anti-NBP60. Most NBP60 was found to be localized in the nuclear envelope fraction of rat liver obtained on cell fractionation followed by immunoblotting. Staining of the nuclei of cultured cells by the antibody was observed on immunofluorescence microscopy. NBP60 was widely detected in rat nuclear fractions prepared from other tissues and also in nuclei of cultured cells derived from other species. It was shown by immunoelectron microscopy that most NBP60 is present in the nuclear envelope and at least some of that is present on nuclear pore complexes. Although NBP60 was localized in the nuclear envelope in interphase cells, it diffused into the cytoplasm in the mitotic phase. The purified NBP60 was highly phosphorylated by a cdc2 mitotic kinase, whereas nuclear pore proteins p144, p62, p60, and p54 were not phosphorylated by the kinase directly. NBP60 was also phosphorylated by protein kinase A, calmodulin-dependent protein kinase II, and casein kinase II. The phosphorylation of NBP60 by cdc2 kinase and/or the other kinases may be related to the change in the protein's location during the mitotic phase.

Primary biliary cirrhosis sera recognize not only gp210 but also proteins of the p62 complex bearing N-acetylglucosamine residues from rat liver nuclear envelope. Anti-p62 complex antibody in PBC

We have recently observed reactivity of primary biliary cirrhosis (PBC) sera with several proteins bearing N-acetylglucosamine residues from rat liver nuclear envelopes. The aim of this study was to characterize the reactive antigens. Sera from 31 patients with PBC, 30 with rheumatoid arthritis (RA) and 30 with Sjögren's syndrome (SS) were examined. Rim-like immunofluorescence staining was observed in 15 of 31 (48%) sera from patients with PBC, in 1 of 30 with RA and in 1 of 30 with SS. Upon immunoblotting using preparations of whole rat liver nuclear envelopes and their Triton X 100-KCl extract as antigen sources, a 200 kDa protein band was observed in 9 of sera with PBC. Furthermore, upon immunoblotting using the wheat germ aggulutinin-bound fraction of rat liver envelope as antigen, 62, 60 and 54 kDa protein bands corresponding to components of the p62 complex in the nuclear pore complex (Kita et al. Biochem. 113, 377-382) were observed in 7, 5 and 6 samples respectively, of the 31 PBC sera. Our data suggest that PBC sera recognize not only the 210 kDa protein but also the p62 complex proteins.

Identification of the site of interaction of the 14-3-3 protein with phosphorylated tryptophan hydroxylase

The 14-3-3 protein family plays a role in a wide variety of cell signaling processes including monoamine synthesis, exocytosis, and cell cycle regulation, but the structural requirements for the activity of this protein family are not known. We have previously shown that the 14-3-3 protein binds with and activates phosphorylated tryptophan hydroxylase (TPH, the rate-limiting enzyme in the biosynthesis of neurotransmitter serotonin) and proposed that this activity might be mediated through the COOH-terminal acidic region of the 14-3-3 molecules. In this report we demonstrate, using a series of truncation mutants of the 14-3-3 eta isoform expressed in Escherichia coli, that the COOH-terminal region, especially restricted in amino acids 171-213, binds indeed with the phosphorylated TPH. This restricted region, which we termed 14-3-3 box I, is one of the structural regions whose sequence is highly conserved beyond species, allowing that the plant 14-3-3 isoform (GF14) could also activate rat brain TPH. The 14-3-3 box I is the first functional region whose activity has directly been defined in the 14-3-3 sequence and may represent a common structural element whereby 14-3-3 interacts with other target proteins such as Raf-1 kinase. The result is consistent with the recently published crystal structure of this protein family, which suggests the importance of the negatively charged groove-like structure in the ligand binding.

[A clinical study of associated bladder tumor in patients with renal pelvic and ureteral tumor]

We investigated the incidence of associated bladder tumor and prognosis in 101 cases with a pathological diagnosis of transitional cell carcinoma, selected from those with renal pelvic and ureteral tumor whom we had encountered over the 18 years between April 1976 and March 1993. Among these 101 cases, the incidence of associated bladder tumor was noted in 42 (41.6%), 23 (22.8%) with coexistence and 19 (18.8%) with subsequence. As for the primary site of renal pelvis and ureter, the coexistence was 15.4% and subsequence 20.5% in renal pelvis, and the coexistence was 24.6% and subsequence 19.3% in ureter, and the coexistence was 60.0% and subsequence 0.0% in both renal pelvis and ureter. The incidence of coexistent bladder tumor was high in both renal pelvis and ureter, but no significant difference was noted. As for the stage, the incidence of coexistence was high in T1, while subsequence was high in T2, but no significant difference was noted. As for the grade, the incidence of coexistence was high in G2, but no significant difference was noted. The 5 year survival rate was 58.2% in those without, 54.2% with coexistence, and 82.5% with subsequent bladder tumor, with a significant difference (p < 0.05) between the last two groups. The interval of subsequent bladder tumor ranged from 4 to 164 months (mean 27.7 months), with the incidence within 2 years being approximately 70.0%. It was found that the renal pelvic and ureteral tumors are frequently associated bladder tumor while associated bladder tumor dose not appear to have an ill effect on the prognosis. Therefore it is necessary that patients with renal pelvic and ureteral tumor be observed closely for 5 years, especially for the initial 2 years.

Separation of membrane proteins solubilized with a nondenaturing detergent and a high salt concentration by hydroxyapatite high-performance liquid chromatography

Ceramic hydroxyapatite high-performance liquid chromatography with a solvent containing high concentrations of salts was used for the separation of membrane proteins solubilized under nondenaturing and high salt conditions. The chromatographic conditions were optimized using sodium cholate as the detergent. By this method, most membrane proteins, prepared from rat liver rough microsomes, were effectively resolved from each other with a protein recovery of more than 90%. The method also allowed the single-step purification of the ribosome-binding protein, p34, from a microsomal membrane protein fraction. The good resolution with this method should be applicable to the isolation and characterization of a variety of membrane proteins on the analytical and semipreparative scales. With only the substitution of sodium cholate with other nondenaturing detergents, this method may also be applicable to the purification of membrane proteins requiring such nondenaturing detergents with retention of their biological activities.

Purification and molecular shape of a 144 kDa protein bearing N-acetylglucosamine residues from rat liver nuclear envelopes

A 144 kDa protein was purified from the WGA-Sepharose bound fraction of a rat liver nuclear envelope salt-extract by hydroxyapatite HPLC (HAP HPLC). Two other, 120 and 86 kDa, proteins were also partially purified from the fraction by a combination of DEAE- and HAP-HPLCs. It was suggested that the 144, 120, and 86 kDa proteins bear GlcNAc residues, and are nucleoporins, because they were purified from nuclear envelopes, reacted with WGA-HRP, and cross-reacted with an antibody against p62 nucleoporin complexes. The sedimentation coefficients and Stokes' radii of these GlcNAc-bearing proteins were determined by glycerol density gradient centrifugation and gel filtration in the presence of 500 mM NaCl. The molecular masses calculated from these values suggested that these three proteins each exist as a monomer under the conditions employed. The axial ratios of the purified 144, 120, and 86 kDa GlcNAc-proteins were estimated to be 35, 31, and 31, respectively. These values suggested that they are rod-shaped molecules. The axial ratio of a purified nucleoporin-complex consisting of 62, 60, and 54 kDa components bearing GlcNAc was shown to be 20. This nucleoporin complex seems to be a rod-shaped complex. From these results, a rod shape is proposed to be a common characteristic of GlcNAc-proteins in nuclear envelopes.

Heat shock protein 90 strongly stimulates the binding of purified estrogen receptor to its responsive element

We previously showed that the 9 S estrogen receptor (ER) could be reconstituted from purified ER and purified heat shock protein 90 (hsp 90). So, we investigated the role of hsp 90 in the binding of purified ER to an estrogen responsive element (ERE) by using the reconstitution system. ER purified from calf uterus showed a very low binding capacity to an ERE from the vitellogenin A2 gene in the gel mobility shift assay. However, the binding was strongly stimulated by reconstitution with hsp 90 and was proportional to the amount of reconstituted 9 S ER. Hsp 70, a typical molecular chaperone and a component of some steroid receptors, did not cause similar stimulation. The equilibrium dissociation constants (Kd) of the occupied and unoccupied 9 S ER for the ERE were the same as each other, indicating that the binding of ER to the ERE was independent of the ligand. H222, a monoclonal antibody which binds to the hormone-binding domain (HBD) of ER, recovered the high affinity ER-ERE binding. The binding of hsp 90 to ER suppressed the Triton X-100 stimulated estradiol-dissociation from the ER. The sedimentation coefficients and Stokes' radii of the purified and unpurified cytosolic ER were compared, and it was shown that the purified ER was not unfolded and had a rather compact structure, similar to the cytosolic ER.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential effects of methylmercury on the phosphorylation of protein species in the brain of acutely intoxicated rats

The in vivo effect of methylmercury (MeHg) on the phosphorylation in vitro of the brain cytosol fraction was examined in acutely poisoned rats (10 mg/kg/day, for 7 days). The total phosphorylation activity, determined in the presence or absence of protein kinase effectors (Ca2+ and cAMP) and substrates (casein, histone and protein kinase C substrate), did not markedly change with the progress of intoxication. Two-dimensional electrophoretic analysis of the phosphorylated cytosol fractions from control and MeHg-treated rats revealed that (1) the extents of phosphorylation of the 24 major protein species in the control rats differed greatly from each other, (2) the effect of MeHg on the phosphorylation was not uniform regarding the individual 24 proteins or the period of intoxication, and (3) in the symptomatic period, many protein species including tubulin subunits showed elevated phosphorylation, while a few protein species showed decreased phosphorylation. These results suggest that the neurotoxic action of MeHg could be mediated through, at least in part, the modification of functional protein species due to excess phosphorylation that leads to impairment of the normal cellular processes.

Purification of a 60 kDa nuclear localization signal binding protein in rat liver nuclear envelopes and characterization of its properties

A nuclear localization signal binding protein in nuclear envelope was studied as the first step to determine the mechanism of nuclear protein recognition by nuclear envelope. The rat liver nuclear envelope extract was resolved by SDS-PAGE and ligand blotted with 125I-labeled nucleoplasmin bearing a strong nuclear localization signal. A nuclear localization signal binding protein with molecular mass of 60 kDa (NBP60) was detected in the extract. NBP60 could be extracted with 2% Triton X-100-1 M KCl but not with 1 M KCl, 2 M urea, or 2% Triton X-100. The protein was partitioned to the lower layer in a two phase system using Triton X-114. These results suggested that the protein is an intrinsic membrane protein and has a hydrophobic surface. This protein was bound to not only nucleoplasmin but also the nuclear localization signal peptide of SV 40 large T-antigen (T-peptide) conjugated to human serum albumin. The binding of NBP60 to nucleoplasmin-Sepharose was inhibited by 50% in the presence of 0.12 mM T-peptide. However, a high concentration of 2.1 mM was necessary, when mutant T-peptide in which the essential amino acid lysine was substituted with threonine was used. These results suggested that NBP60 binds specifically to nuclear localization signals. NBP60 extracted from the nuclear envelope was purified by nucleoplasmin-Sepharose affinity chromatography following hydroxyapatite high performance liquid chromatography.

Purification and characterization of a nuclear pore glycoprotein complex containing p62

It is known that nucleoporins, a family of glycoproteins with N-acetylglucosamine that are found in nuclear pore complexes, are essential for nuclear import and export. A major component of the family, p62, was purified from a salt extract of rat liver nuclear envelopes by wheat germ agglutinin-Sepharose affinity chromatography and DEAE-anion exchange HPLC. p62 was purified as a complex with two glycoproteins of 60 and 54 kDa. The presence of the complex was confirmed by gel filtration, glycerol density gradient centrifugation, and cross-linking experiments. The molecular ratio of the 62-, 60-, and 54-kDa components of the complex was estimated to be 1: 1.1 +/- 0.2: 1.7 +/- 0.3 from the intensity of Coomassie Blue staining of SDS-PAGE gels. The complex was stable against 1 M NaCl, 1% Triton X-100, and 2 M urea. The Stokes' radius and sedimentation coefficient of the complex are 8.0 nm and 6.7 S. The molecular mass and frictional ratio of the complex were estimated to be about 231 kDa and 2.0, respectively. p62 and p54 were acidic and neutral proteins, respectively, exhibiting charge heterogeneities, and p60 was assumed to be a basic protein. p60 tended to undergo proteolytic degradation to a 47-kDa fragment.

Dietary casein and soybean protein affect the concentrations of serum cholesterol, triglyceride and free amino acids in rats

This work was undertaken to investigate the concentrations of free amino acids in blood after food was withheld from growing, male Wistar rats fed cholesterol-free, low fat (1 g corn oil/100 g) diets with casein or soybean protein for 2 wk. A diet containing 22.5 or 23.5 g/100 g of soybean protein was hypocholesterolemic compared with a diet containing 20.0 g casein/100 g diet. A comparison of serum amino acids in soybean protein-fed vs. casein-fed rats showed that, whereas concentrations of many amino acids were lower in the soybean protein-fed rats compared with the casein-fed groups, glycine was the only amino acid having a higher concentration. Further, alanine was significantly lower in the soybean protein-fed rats compared with the casein-fed rats, and the protein-induced differences in glycine and alanine concentrations of unfed rats were reproducible. When diets containing 15.0% casein or 30.0% soybean protein, a casein diet supplemented with glycine and a soybean protein diet supplemented with methionine were compared, the changes in serum glycine and alanine correlated with the changes in serum cholesterol. Concentrations of several amino acids, particularly valine, leucine and tyrosine, also changed when serum cholesterol concentrations varied, but these effects could not be explained by our experiments. The results suggest that a change in serum concentration of glycine and alanine of unfed rats may be related to the change in serum cholesterol concentration.

In vitro formation of estrogen receptor-heat shock protein 90 complexes

We previously showed that the 9 S estrogen receptor can be reconstituted from purified vero ER (estradiol binding subunit) and purified hsp 90 (heat shock protein 90) in vitro [Inano, K. et al. (1990) FEBS Lett. 267, 157-159]. In this study, we further characterized our reconstitution system to investigate the mechanism underlying the formation of 9 S ER. When a vero ER preparation stored at 4 degrees C for more than 20 h after affinity chromatography was used for the reconstitution of 9 S ER, 0.5 M NaSCN was essential, but not Na2MoO4 or other reagents. When, however, vero ER was used within 3 h after dissociation from an affinity resin, 9 S ER could be reconstituted in a relatively high yield without NaSCN. Moreover, if such a fresh vero ER preparation was used, 9 S ER could be reconstituted in the absence of NaSCN from not only unoccupied vero ER but also the occupied form. From these results it was suggested that the conformation of purified vero ER tends to change quickly in a time dependent manner, and so a chemical perturbant, NaSCN, is generally necessary for the reconstitution of 9 S ER from purified vero ER and purified hsp 90. The concentration of hsp 90 required for the reconstitution was only about 1.0 microM, which was lower than its physiological concentration. Based on these results, the mechanism underlying the formation of 9 S ER was discussed.

Hypocholesterolaemic effect of banana (Musa sapientum L. var. Cavendishii) pulp in the rat fed on a cholesterol-containing diet

The pulp of banana fruit (Musa sapientum L. var. Cavendishii) was examined for its cholesterol-lowering effect with male rats fed on a diet containing lard (50 g/kg) and cholesterol (5 g/kg). Freeze-dried banana pulp showed a marked cholesterol-lowering effect when incorporated into a diet at the level of 300 or 500 g/kg, while the banana pulp dried in a hot-air current (65 degrees) did not. Starch and tannin prepared from banana pulp were not responsible for the cholesterol-lowering effect. The results also suggest that banana lipids did not affect the concentration of serum cholesterol. Feeding of dopamine, n-epinephrine and serotonin tended to raise the concentration of serum cholesterol. Thus, all the substances tested which were thought to be susceptible to influence by hot-air drying were unlikely to be responsible for the hypocholesterolaemic effect. However, both soluble and insoluble fibres fractionated from banana pulp had a cholesterol-lowering effect, with the exception of cellulose. It was assumed that a browning reaction undergone during hot-air drying might be related to the disappearance of the hypocholesterolaemic effect of banana pulp dried in a hot-air current. The results obtained support the conclusion that soluble and insoluble components of dietary fibre participate in the hypocholesterolaemic effect of banana pulp.

Characterization of the hydrophobic region of heat shock protein 90

The modes of binding of heat shock protein 90 with phenyl-Sepharose, myristoylated AE-cellulose, and monomyristoylated lysozyme were studied to characterize a hydrophobic region(s) on the surface of the heat shock protein 90 molecule and the following results were obtained. (1) The binding of heat shock protein 90 with phenyl-Sepharose was inhibited by the addition of 30% ethylene glycol. This indicates that the binding involves a hydrophobic interaction. (2) The binding was strengthened by the addition of 10 mM Mg2+, Ca2+, Sr2+, and Ba2+ ions, but not by K+ or Na+ ions. (3) The binding of hsp 90 with phenyl-Sepharose decreased initially and then increased as the temperature was increased from 0 to 50 degrees C, with a minimum at around 35 degrees C. (4) Lowering the pH stimulated the binding of hsp 90 with phenyl-Sepharose. (5) Heat shock protein 90 bound to myristoylated AE-cellulose, which has aliphatic hydrophobic residues, but not to acetylated AE-cellulose. (6) Heat shock protein 90 bound to monomyristoylated lysozyme, but not to control unmodified lysozyme. Based on these results, the possible function of the hydrophobic region(s) of heat shock protein 90 in the interaction with hydrophobic proteins is discussed.

Reconstitution of the 9 S estrogen receptor with heat shock protein 90

As a first step in the investigation of the reconstitution of steroid hormone receptor systems, we studied the reconstitution of 9 S estrogen receptor (ER) from purified vero ER, which is the estradiol binding subunit, and heat shock protein 90 (hsp 90). By using a phosphate buffer containing molybdate, thiocyanate, dimethylformamide, glycerol, etc., vero ER could be converted to 9 S ER with hsp 90, but not with the control protein, ovalbumin. Inactivation of ER during the reconstitution was suppressed partially by hsp 90, but not by ovalbumin. Like native 8 S ER, the reconstituted ER was sedimented at about 8.9 S and 4.6 S on glycerol gradient centrifugation in low and high salt buffers, respectively.

Ceramic hydroxyapatite high-performance liquid chromatography of complexes membrane protein and sodium dodecylsulfate

Ceramic hydroxyapatite high-performance liquid chromatography was examined as a chromatographic method by which complexes of whole membrane proteins and sodium dodecyl sulfate could be analyzed. The chromatographic conditions were optimized using the erythrocyte membrane as a model. Whole proteins, including membrane proteins larger than 100 kDa, were eluted as sharp peaks from the column and separated well from each other under optimum conditions. This method gave better resolution of protein-SDS complexes than other chromatographic methods reported so far. The sodium dodecyl sulfate complexes of 24 well characterized proteins were analyzed by this method and their retention times were examined. The positive correlation of the retention time with log (molecular mass) and log sigma (hydrophobicity of amino acids) but not with the isoelectric point, was observed. Based on these results, the mechanism underlying the interaction of protein-SDS complexes with ceramic hydroxyapatite was discussed.