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1.
Appl Biochem Biotechnol ; 193(6): 1836-1852, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33570730

RESUMO

Small heat shock proteins (sHSPs), often known as molecular chaperones, are most prevalent in nature. Under certain stress-induced conditions, these sHSPs act as an ATP-independent variation and thus prevent the inactivation of various non-native substrate proteins and their aggregation. They also assist other ATP-dependent chaperones in the refolding of these substrates. In the case of prokaryotes and lower eukaryotes, the chaperone functions of sHSPs can bind a wide range of cellular proteins but preferentially protect translation-related proteins and metabolic enzymes. Eukaryotes usually encode a larger number of sHSPs than those of prokaryotes. The chaperone functions of mammalian sHSPs are regulated by phosphorylation in cells and also by temperature. Their sHSPs have different sub-cellular compartments and cell/tissue specificity. The substrate proteins of mammalian sHSPs or eukaryotic sHSPs accordingly reflect their multi-cellular complexity. The sHSPs of animals play roles in different physiological processes as cell differentiation, apoptosis, and longevity. In this work, the characterization, location, tissue specificity, and functional diversity of sHSPs from seven different mammalian species with special emphasis on humans have been studied. Through this extensive work, a novel and significant attempt have been made to classify them based on their omnipresence, tissue specificity, localization, secondary structure, probable mutations, and evolutionary significance.


Assuntos
Simulação por Computador , Proteínas de Choque Térmico Pequenas , Animais , Bovinos , Cães , Proteínas de Choque Térmico Pequenas/química , Proteínas de Choque Térmico Pequenas/classificação , Proteínas de Choque Térmico Pequenas/metabolismo , Humanos , Macaca mulatta , Camundongos , Especificidade de Órgãos , Pan troglodytes , Fosforilação , Estrutura Secundária de Proteína
2.
Int J Biol Macromol ; 167: 1575-1578, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33212104

RESUMO

Small heat shock protein (sHSP) is a superfamily of molecular chaperone and is found from archaea to human. Recent researches have demonstrated that sHSPs participate in a series of biological processes and are even closely associated with serious diseases. Since sHSP is a very large superfamily and members from different superfamilies exhibit distinct functions, accurate classification of the subfamily of sHSP will be helpful for unrevealing its functions. In the present work, a support vector machine-based method was proposed to classify the subfamily of sHSPs. In the 10-fold cross validation test, an overall accuracy of 93.25% was obtained for classifying the subfamily of sHSPs. The superiority of the proposed method was also demonstrated by comparing it with the other methods. It is anticipated that the proposed method will become a useful tool for classifying the subfamily of sHSPs.


Assuntos
Biologia Computacional/métodos , Dipeptídeos/classificação , Proteínas de Choque Térmico Pequenas/classificação , Aprendizado de Máquina , Sequência de Aminoácidos , Animais , Bases de Dados de Proteínas , Dipeptídeos/química , Dipeptídeos/genética , Proteínas de Choque Térmico Pequenas/química , Proteínas de Choque Térmico Pequenas/genética , Humanos , Proteômica/métodos , Alinhamento de Sequência
3.
G3 (Bethesda) ; 6(10): 3027-3034, 2016 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-27565886

RESUMO

In plants, fruit maturation and oxidative stress can induce small heat shock protein (sHSP) synthesis to maintain cellular homeostasis. Although the tomato reference genome was published in 2012, the actual number and functionality of sHSP genes remain unknown. Using a transcriptomic (RNA-seq) and evolutionary genomic approach, putative sHSP genes in the Solanum lycopersicum (cv. Heinz 1706) genome were investigated. A sHSP gene family of 33 members was established. Remarkably, roughly half of the members of this family can be explained by nine independent tandem duplication events that determined, evolutionarily, their functional fates. Within a mitochondrial class subfamily, only one duplicated member, Solyc08g078700, retained its ancestral chaperone function, while the others, Solyc08g078710 and Solyc08g078720, likely degenerated under neutrality and lack ancestral chaperone function. Functional conservation occurred within a cytosolic class I subfamily, whose four members, Solyc06g076570, Solyc06g076560, Solyc06g076540, and Solyc06g076520, support ∼57% of the total sHSP RNAm in the red ripe fruit. Subfunctionalization occurred within a new subfamily, whose two members, Solyc04g082720 and Solyc04g082740, show heterogeneous differential expression profiles during fruit ripening. These findings, involving the birth/death of some genes or the preferential/plastic expression of some others during fruit ripening, highlight the importance of tandem duplication events in the expansion of the sHSP gene family in the tomato genome. Despite its evolutionary diversity, the sHSP gene family in the tomato genome seems to be endowed with a core set of four homeostasis genes: Solyc05g014280, Solyc03g082420, Solyc11g020330, and Solyc06g076560, which appear to provide a baseline protection during both fruit ripening and heat shock stress in different tomato tissues.


Assuntos
Duplicação Gênica , Genes de Plantas , Proteínas de Choque Térmico Pequenas/genética , Família Multigênica , Solanum lycopersicum/genética , Sequências de Repetição em Tandem , Biologia Computacional/métodos , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Proteínas de Choque Térmico Pequenas/classificação , Proteínas de Choque Térmico Pequenas/metabolismo , Solanum lycopersicum/metabolismo , Anotação de Sequência Molecular , Filogenia , Transporte Proteico , Transcriptoma
4.
Plant Physiol ; 172(2): 1221-1236, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27474115

RESUMO

The ubiquitous small heat shock proteins (sHSPs) are well documented to act in vitro as molecular chaperones to prevent the irreversible aggregation of heat-sensitive proteins. However, the in vivo activities of sHSPs remain unclear. To investigate the two most abundant classes of plant cytosolic sHSPs (class I [CI] and class II [CII]), RNA interference (RNAi) and overexpression lines were created in Arabidopsis (Arabidopsis thaliana) and shown to have reduced and enhanced tolerance, respectively, to extreme heat stress. Affinity purification of CI and CII sHSPs from heat-stressed seedlings recovered eukaryotic translation elongation factor (eEF) 1B (α-, ß-, and γ-subunits) and eukaryotic translation initiation factor 4A (three isoforms), although the association with CI sHSPs was stronger and additional proteins involved in translation were recovered with CI sHSPs. eEF1B subunits became partially insoluble during heat stress and, in the CI and CII RNAi lines, showed reduced recovery to the soluble cell fraction after heat stress, which was also dependent on HSP101. Furthermore, after heat stress, CI sHSPs showed increased retention in the insoluble fraction in the CII RNAi line and vice versa. Immunolocalization revealed that both CI and CII sHSPs were present in cytosolic foci, some of which colocalized with HSP101 and with eEF1Bγ and eEF1Bß. Thus, CI and CII sHSPs have both unique and overlapping functions and act either directly or indirectly to protect specific translation factors in cytosolic stress granules.


Assuntos
Proteínas de Choque Térmico Pequenas/metabolismo , Temperatura Alta , Fatores de Alongamento de Peptídeos/metabolismo , Proteínas de Plantas/metabolismo , Fatores de Transcrição/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Eletroforese em Gel Bidimensional , Fator de Iniciação 4A em Eucariotos/genética , Fator de Iniciação 4A em Eucariotos/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Choque Térmico Pequenas/classificação , Proteínas de Choque Térmico Pequenas/genética , Immunoblotting , Fatores de Alongamento de Peptídeos/genética , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Ligação Proteica , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , Interferência de RNA , Plântula/genética , Plântula/metabolismo , Estresse Fisiológico , Espectrometria de Massas em Tandem , Fatores de Transcrição/genética
5.
Ultramicroscopy ; 164: 46-50, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-27010412

RESUMO

An alternative method has been assessed; diffraction patterns derived from the single particle data set were used to perform the first round of classification in creating the initial averages for proteins data with symmetrical morphology. The test protein set was a collection of Caenorhabditis elegans small heat shock protein 17 obtained by Cryo EM, which has a tetrahedral (12-fold) symmetry. It is demonstrated that the initial classification on diffraction patterns is workable as well as the real-space classification that is based on the phase contrast. The test results show that the information from diffraction patterns has the enough details to make the initial model faithful. The potential advantage using the alternative method is twofold, the ability to handle the sets with poor signal/noise or/and that break the symmetry properties.


Assuntos
Proteínas de Caenorhabditis elegans/classificação , Proteínas de Choque Térmico Pequenas/classificação , Microscopia Eletrônica de Transmissão , Animais , Caenorhabditis elegans/química , Proteínas de Caenorhabditis elegans/química , Proteínas de Caenorhabditis elegans/ultraestrutura , Microscopia Crioeletrônica , Cristalização , Proteínas de Choque Térmico Pequenas/química , Proteínas de Choque Térmico Pequenas/ultraestrutura , Processamento de Imagem Assistida por Computador , Imageamento Tridimensional
6.
Cell Stress Chaperones ; 20(1): 23-35, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24947609

RESUMO

We identify and characterize 14 small heat-shock protein (sHSP) genes from the diamondback moth (DBM), Plutella xylostella (L.), a destructive pest. Phylogenetic analyses indicate that, except for sHSP18.8 and sHSP19.22, the other 12 DBM sHSPs belong to five known insect sHSP groups. Developmental expression analysis revealed that most sHSPs peaked in the pupal and adult stages. The transcripts of sHSPs display tissue specificity with two exhibiting constitutive expression in four tested tissues. Expression of sHSP18.8 in fourth instar larvae is not induced by the tested abiotic stressors, and unless sHSP21.8 is not sensitive to thermal stress, 12 sHSPs are significantly up-regulated. The messenger RNA (mRNA) levels of all sHSPs are reduced under oxidative stress. Food deprivation leads to significant down-regulation of three sHSPs. The majority of sHSPs show expression variation to various heavy metals, whereas mRNA abundances of sHSP22.1 and sHSP 28.9 are reduced by four heavy metals. The responses of sHSPs to indoxacarb and cantharidin are varied. Beta-cypermethrin and chlorfenapyr exposure results in an increase of 13 sHSP transcripts and a reduction of 12 sHSP transcripts, respectively. These results show that different sHSPs might play distinct roles in the development and regulation of physiological activities, as well as in response to various abiotic stresses of DBM.


Assuntos
Regulação da Expressão Gênica/efeitos dos fármacos , Proteínas de Choque Térmico Pequenas/metabolismo , Lepidópteros/metabolismo , Sequência de Aminoácidos , Animais , Proteínas de Choque Térmico Pequenas/classificação , Proteínas de Choque Térmico Pequenas/genética , Larva/metabolismo , Lepidópteros/crescimento & desenvolvimento , Dados de Sequência Molecular , Óvulo/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Praguicidas/toxicidade , Filogenia , RNA Mensageiro/metabolismo , Alinhamento de Sequência , Inanição , Temperatura , Transcriptoma
7.
J Mol Biol ; 425(10): 1683-96, 2013 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-23416558

RESUMO

Small heat shock proteins (sHSPs) are virtually ubiquitous stress proteins that are also found in many normal tissues and accumulate in diseases of protein folding. They generally act as ATP-independent chaperones to bind and stabilize denaturing proteins that can be later reactivated by ATP-dependent Hsp70/DnaK, but the mechanism of substrate capture by sHSPs remains poorly understood. A majority of sHSPs form large oligomers, a property that has been linked to their effective chaperone action. We describe AtHsp18.5 from Arabidopsis thaliana, demonstrating that it is dimeric and exhibits robust chaperone activity, which adds support to the model that suboligomeric sHSP forms are a substrate binding species. Notably, like oligomeric sHSPs, when bound to substrate, AtHsp18.5 assembles into large complexes, indicating that reformation of sHSP oligomeric contacts is not required for assembly of sHSP-substrate complexes. Monomers of AtHsp18.5 freely exchange between dimers but fail to coassemble in vitro with dodecameric plant cytosolic sHSPs, suggesting that AtHsp18.5 does not interact by coassembly with these other sHSPs in vivo. Data from controlled proteolysis and hydrogen-deuterium exchange coupled with mass spectrometry show that the N- and C-termini of AtHsp18.5 are highly accessible and lack stable secondary structure, most likely a requirement for substrate interaction. Chaperone activity of a series of AtHsp18.5 truncation mutants confirms that the N-terminal arm is required for substrate protection and that different substrates interact differently with the N-terminal arm. In total, these data imply that the core α-crystallin domain of the sHSPs is a platform for flexible arms that capture substrates to maintain their solubility.


Assuntos
Proteínas de Arabidopsis/química , Arabidopsis/química , Proteínas de Choque Térmico Pequenas/química , Proteínas de Choque Térmico Pequenas/classificação , Proteínas de Choque Térmico/química , Multimerização Proteica , Sequência de Aminoácidos , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/classificação , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Choque Térmico/classificação , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico Pequenas/metabolismo , Modelos Moleculares , Dados de Sequência Molecular , Ligação Proteica , Dobramento de Proteína , Homologia de Sequência de Aminoácidos
8.
Cell Stress Chaperones ; 17(5): 539-51, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22351490

RESUMO

Small heat shock proteins (sHSPs) play an important role in the cellular defense of prokaryotic and eukaryotic organisms against a variety of internal and external stressors. In this study, a cDNA clone encoding a member of the α-crystallin/sHSP family, termed AccHsp27.6, was isolated from Apis cerana cerana. The full-length cDNA is 1,014 bp in length and contains a 708-bp open reading frame encoding a protein of 236 amino acids with a calculated molecular weight of 27.6 kDa and an isoelectric point of 7.53. Seven putative heat shock elements and three NF-κB binding sites were present in the 5'-flanking region, suggesting a possible function in immunity. A semi-quantitative RT-PCR analysis indicated that AccHsp27.6 was expressed in all tested tissues and at different developmental stages. Furthermore, expression of the AccHsp27.6 transcript was induced by exposure to heat shock, H(2)O(2), a number of different chemicals (including SO(2), formaldehyde, alcohol, acetone, chloroform, and the pesticides phoxime and acetamiprid), and the microbes Staphylococcus aureus and Micrococcus luteus. In contrast, the mRNA expression could be repressed by CO(2), the pesticides pyriproxyfen and cyhalothrin, and the microbes Bacillus subtilis and Pseudomonas aeruginosa. Notably, the recombinant AccHsp27.6 protein exhibited significant in vitro molecular chaperone activity and antimicrobial activity. Taken together, these results suggest that AccHsp27.6 might play an important role in the response to abiotic and biotic stresses and in immune reactions.


Assuntos
Proteínas de Choque Térmico Pequenas/metabolismo , Sequência de Aminoácidos , Animais , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Bactérias/patogenicidade , Sequência de Bases , Abelhas/efeitos dos fármacos , Abelhas/metabolismo , Abelhas/efeitos da radiação , Sítios de Ligação , Dióxido de Carbono/farmacologia , Clonagem Molecular , Testes de Sensibilidade a Antimicrobianos por Disco-Difusão , Proteínas de Choque Térmico Pequenas/classificação , Proteínas de Choque Térmico Pequenas/genética , Dados de Sequência Molecular , NF-kappa B/metabolismo , Filogenia , Estrutura Terciária de Proteína , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/farmacologia , Raios Ultravioleta
9.
Planta ; 235(3): 453-71, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21947620

RESUMO

Physical clustering of genes has been shown in plants; however, little is known about gene clusters that have different functions, particularly those expressed in the tomato fruit. A class I 17.6 small heat shock protein (Sl17.6 shsp) gene was cloned and used as a probe to screen a tomato (Solanum lycopersicum) genomic library. An 8.3-kb genomic fragment was isolated and its DNA sequence determined. Analysis of the genomic fragment identified intronless open reading frames of three class I shsp genes (Sl17.6, Sl20.0, and Sl20.1), the Sl17.6 gene flanked by Sl20.1 and Sl20.0, with complete 5' and 3' UTRs. Upstream of the Sl20.0 shsp, and within the shsp gene cluster, resides a box C/D snoRNA cluster made of SlsnoR12.1 and SlU24a. Characteristic C and D, and C' and D', boxes are conserved in SlsnoR12.1 and SlU24a while the upstream flanking region of SlsnoR12.1 carries TATA box 1, homol-E and homol-D box-like cis sequences, TM6 promoter, and an uncharacterized tomato EST. Molecular phylogenetic analysis revealed that this particular arrangement of shsps is conserved in tomato genome but is distinct from other species. The intronless genomic sequence is decorated with cis elements previously shown to be responsive to cues from plant hormones, dehydration, cold, heat, and MYC/MYB and WRKY71 transcription factors. Chromosomal mapping localized the tomato genomic sequence on the short arm of chromosome 6 in the introgression line (IL) 6-3. Quantitative polymerase chain reaction analysis of gene cluster members revealed differential expression during ripening of tomato fruit, and relatively different abundances in other plant parts.


Assuntos
Cromossomos de Plantas/genética , Proteínas de Choque Térmico Pequenas/genética , Proteínas de Plantas/genética , RNA Nucleolar Pequeno/genética , Solanum lycopersicum/genética , Sequência de Aminoácidos , Frutas/genética , Regulação da Expressão Gênica de Plantas , Proteínas de Choque Térmico Pequenas/química , Proteínas de Choque Térmico Pequenas/classificação , Dados de Sequência Molecular , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/classificação , Reação em Cadeia da Polimerase , RNA Nucleolar Pequeno/química , RNA Nucleolar Pequeno/classificação , Homologia de Sequência de Aminoácidos
10.
Physiol Rev ; 91(4): 1123-59, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22013208

RESUMO

Modern classification of the family of human small heat shock proteins (the so-called HSPB) is presented, and the structure and properties of three members of this family are analyzed in detail. Ubiquitously expressed HSPB1 (HSP27) is involved in the control of protein folding and, when mutated, plays a significant role in the development of certain neurodegenerative disorders. HSPB1 directly or indirectly participates in the regulation of apoptosis, protects the cell against oxidative stress, and is involved in the regulation of the cytoskeleton. HSPB6 (HSP20) also possesses chaperone-like activity, is involved in regulation of smooth muscle contraction, has pronounced cardioprotective activity, and seems to participate in insulin-dependent regulation of muscle metabolism. HSPB8 (HSP22) prevents accumulation of aggregated proteins in the cell and participates in the regulation of proteolysis of unfolded proteins. HSPB8 also seems to be directly or indirectly involved in regulation of apoptosis and carcinogenesis, contributes to cardiac cell hypertrophy and survival and, when mutated, might be involved in development of neurodegenerative diseases. All small heat shock proteins play important "housekeeping" roles and regulate many vital processes; therefore, they are considered as attractive therapeutic targets.


Assuntos
Proteínas de Choque Térmico Pequenas/química , Proteínas de Choque Térmico Pequenas/fisiologia , Apoptose/fisiologia , Citoesqueleto/fisiologia , Proteínas de Choque Térmico Pequenas/classificação , Humanos , Contração Muscular/fisiologia , Doenças Neurodegenerativas/fisiopatologia , Dobramento de Proteína
11.
J Insect Physiol ; 57(7): 908-14, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21510953

RESUMO

Small heat shock proteins (sHsps) are probably the most diverse in structure and function among the various superfamilies of stress proteins. To explore the diverse functions of insect sHsps, six sHsp cDNAs were cloned from the midgut cDNA library of Spodoptera litura, and a phylogenetic tree was constructed based on the conserved α-crystalline domains. The expression patterns in different developmental stages and tissues, as well as in response to both thermal and 20-hydroxyecdysone (20E) induction, were studied by real-time quantitative PCR. Based on sequence characteristics and phylogenetic relationships, the six SlHsps were classified into three independent groups: BmHsp20.4 like proteins (SlHsp19.7, 20.4, 20.7, 20.8), BmHsp26.6 like protein (SlHsp20), and BmHsp21.4 like protein (SlHsp21.4). All the SlHsps showed highest expression in the Malpighian tubules. The four BmHsp20.4 like protein genes were up-regulated by thermal stress and showed expression variation with development. SlHsp20 exhibited lower expression levels in both egg and larval stages than in pupal and adult stages. SlHsp21.4 retained a constant expression level during all life stages. The expression of both SlHsp20.4 and SlHsp20.8 was significantly up-regulated by 20E. These results indicate that sHsps play diverse functions in S. litura: the BmHsp20.4 like proteins are involved in both thermal adaptation and development; SlHsp20 does not respond to temperature stress but possibly plays a role in metamorphosis; SlHsp21.4 may have no direct relationship with either thermal response or development.


Assuntos
Proteínas de Choque Térmico Pequenas/genética , Proteínas de Insetos/genética , Spodoptera/genética , Sequência de Aminoácidos , Animais , Clonagem Molecular , DNA Complementar/genética , Ecdisterona/metabolismo , Perfilação da Expressão Gênica , Proteínas de Choque Térmico Pequenas/classificação , Proteínas de Choque Térmico Pequenas/metabolismo , Proteínas de Insetos/metabolismo , Larva/genética , Larva/metabolismo , Dados de Sequência Molecular , Óvulo/classificação , Óvulo/metabolismo , Filogenia , Reação em Cadeia da Polimerase , Pupa/classificação , Pupa/genética , Pupa/metabolismo , Alinhamento de Sequência , Spodoptera/classificação , Spodoptera/crescimento & desenvolvimento , Spodoptera/metabolismo , Temperatura , alfa-Cristalinas/genética
12.
Cell Stress Chaperones ; 15(6): 897-904, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20405260

RESUMO

Small heat shock proteins (sHSPs) encompass a widespread and diverse class of proteins with molecular chaperone activity. In the present study, two sHSP isoforms (VpsHSP-1 and VpsHSP-2) were cloned from Venerupis philippinarum haemocytes by Rapid Amplification of cDNA Ends (RACE) approaches. The expression profiles of these two genes under Vibrio anguillarum challenge and cadmium exposure were investigated by quantitative real-time reverse transcriptase polymerase chain reaction. The bacterial challenge could significantly up-regulate the mRNA expression of both VpsHSP-1 and VpsHSP-2, with the increase of VpsHSP-2 expression occurred earlier than that of VpsHSP-1. During the cadmium exposure experiment, the expression level of both VpsHSP-1 and VpsHSP-2 decreased significantly with larger amplitude in VpsHSP-2. As time progressed, the expression levels of both genes were up-regulated with more increment in the low-chemical exposure groups. The differences in the response to pathogen stimulation and cadmium exposure indicated that there were functional diversity between the two structurally different molecules, VpsHSP-1 and VpsHSP-2, and they probably played distinct roles in mediating the environmental stress and immune responses in calm.


Assuntos
Bivalves/metabolismo , Cádmio/toxicidade , Proteínas de Choque Térmico Pequenas/metabolismo , Vibrio/patogenicidade , Sequência de Aminoácidos , Animais , Bivalves/efeitos dos fármacos , Bivalves/microbiologia , Perfilação da Expressão Gênica , Proteínas de Choque Térmico Pequenas/classificação , Proteínas de Choque Térmico Pequenas/genética , Dados de Sequência Molecular , Filogenia , Alinhamento de Sequência , Fatores de Tempo
13.
Cell Stress Chaperones ; 15(4): 457-61, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19921466

RESUMO

The presence of an alpha-crystallin domain documents the evolutionary relatedness of the ubiquitous family of small heat shock proteins. Sequence and three-dimensional structure provide no evidence for the presence of such a domain in HSPC034, recently proposed as the 11th member of the human HSPB family. Also, phylogenetic analyses detect no relationship between HSPC034 and the human HSPB1-10 sequences. Arguments are provided as to why inclusion in the HSPB family of proteins like HSPC034, which resemble small heat shock proteins in being heat-inducible and having chaperone-like properties and a low monomeric mass, but are evolutionarily unrelated, is misleading and confusing.


Assuntos
Proteínas de Choque Térmico Pequenas/classificação , Proteínas/classificação , Sequência de Aminoácidos , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Dados de Sequência Molecular , Filogenia , Estrutura Terciária de Proteína , Alinhamento de Sequência , Terminologia como Assunto , alfa-Cristalinas/química
14.
Cell Stress Chaperones ; 14(1): 105-11, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18663603

RESUMO

The expanding number of members in the various human heat shock protein (HSP) families and the inconsistencies in their nomenclature have often led to confusion. Here, we propose new guidelines for the nomenclature of the human HSP families, HSPH (HSP110), HSPC (HSP90), HSPA (HSP70), DNAJ (HSP40), and HSPB (small HSP) as well as for the human chaperonin families HSPD/E (HSP60/HSP10) and CCT (TRiC). The nomenclature is based largely on the more consistent nomenclature assigned by the HUGO Gene Nomenclature Committee and used in the National Center of Biotechnology Information Entrez Gene database for the heat shock genes. In addition to this nomenclature, we provide a list of the human Entrez Gene IDs and the corresponding Entrez Gene IDs for the mouse orthologs.


Assuntos
Proteínas de Choque Térmico/classificação , Terminologia como Assunto , Animais , Chaperoninas/classificação , Chaperoninas/genética , Proteínas de Choque Térmico HSP110/classificação , Proteínas de Choque Térmico HSP40/classificação , Proteínas de Choque Térmico HSP70/classificação , Proteínas de Choque Térmico HSP90/classificação , Proteínas de Choque Térmico Pequenas/classificação , Humanos , Camundongos , Chaperonas Moleculares/classificação , Chaperonas Moleculares/genética
15.
Biotechnol Adv ; 26(6): 591-609, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18789382

RESUMO

Small heat shock proteins (sHsps) exist in almost all organisms. Most organisms have more than one sHsp, but their number can be as high as 65, as found in the eukaryote, Vitis vinifera. The function of sHsps is well-known; they confer thermotolerance to cellular cultures and proteins in cellular extracts during prolonged incubations at elevated temperatures. This demonstrates the ability of sHsps to protect cellular proteins, and to maintain cellular viability under conditions of intensive stress, such as heat shock or chemical treatments. sHsps have several properties that distinguish them from heat shock proteins (Hsps): they function as ATP-independent chaperones, require the flexible assembly and reassembly of oligomeric complex structures for their activation, and exhibit a wide range of substrate-binding capacities. Recent studies indicate that sHsps have important biological functions in thermostability, disaggregation, and proteolysis inhibition. These functions can be harnessed for various applications, including nanobiotechnology, proteomics, bioproduction, and bioseparation. In this review, we discuss the properties and diversity of microbial sHsps, as well as their potential uses in the biotechnology industry.


Assuntos
Proteínas de Bactérias , Biotecnologia/métodos , Proteínas de Choque Térmico Pequenas , Proteínas de Bactérias/química , Proteínas de Bactérias/classificação , Proteínas de Bactérias/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas de Choque Térmico Pequenas/química , Proteínas de Choque Térmico Pequenas/classificação , Proteínas de Choque Térmico Pequenas/metabolismo , Análise Serial de Proteínas , Dobramento de Proteína , Proteômica , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo
17.
Ann Bot ; 99(3): 461-75, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17293350

RESUMO

BACKGROUND AND AIMS: Evolutionary and ecological roles of the chloroplast small heat shock protein (CPsHSP) have been emphasized based on variations in protein contents; however, DNA sequence variations related to the evolutionary and ecological roles of this gene have not been investigated. In the present study, a basal angiosperm, Machilus, together with the eudicot Rhododendron were used to illustrate the evolutionary dynamics of gene divergence in CPsHSPs. METHODS: Degenerate primers were used to amplify CPsHSP-related sequences from 16 Rhododendron and eight Machilus species that occur in Taiwan. Manual DNA sequence alignment was carried out according to the deduced amino acid sequence alignment performed by CLUSTAL X. A neighbour-joining tree was generated in MEGA using conceptual translated amino acid sequences from consensus sequences of cloned CPsHSP genes from eight Machilus and 16 Rhododendron species as well as amino acid sequences of CPsHSPs from five monocots and seven other eudicots acquired from GenBank. CPsHSP amino acid sequences of Funaria hygrometrica were used as the outgroups. The aligned DNA and amino acid sequences were used to estimate several parameters of sequence divergence using the MEGA program. Separate Bayesian inference of DNA sequences of Rhododendron and Machilus species was analysed and the resulting gene trees were used for detection of putative positively selected amino acid sites by the Codeml program implemented in the PAML package. Mean hydrophobicity profile analysis was performed with representative amino acid sequences for both Rhododendron and Machilus species by the Bioedit program. The computer program SplitTester was used to examine whether CPsHSPs of Rhododendron lineages and duplicate copies of the Machilus CPsHSPs have evolved functional divergence based on the hydrophobicity distance matrix. KEY RESULTS: Only one copy of the CPsHSP was found in Rhododendron. However, a higher evolutionary rate of amino acid substitutions in the Hymenanthes lineage of Rhododendron was inferred. Two positively selected amino acid sites may have resulted in higher hydrophobicity in the region of the alpha-crystallin domain (ACD) of the CPsHSP. By contrast, the basal angiosperm, Machilus, possessed duplicate copies of the CPsHSP, which also differed in their evolutionary rates of amino acid substitutions. However, no apparent relationship of ecological relevance toward the positively selected amino acid sites was found in Machilus. CONCLUSIONS: Divergent evolution was found for both Rhododendron lineages and the paralogues of CPsHSP in Machilus that were directed to the shift in hydrophobicity in the ACD and/or methionine-rich region, which might have played important roles in molecular chaperone activity.


Assuntos
Cloroplastos/genética , Evolução Molecular , Proteínas de Choque Térmico Pequenas/genética , Lauraceae/genética , Rhododendron/genética , Sequência de Aminoácidos , Dosagem de Genes , Variação Genética , Proteínas de Choque Térmico Pequenas/química , Proteínas de Choque Térmico Pequenas/classificação , Proteínas de Choque Térmico Pequenas/fisiologia , Interações Hidrofóbicas e Hidrofílicas , Dados de Sequência Molecular , Filogenia , Estrutura Terciária de Proteína , Alinhamento de Sequência
18.
Nat Struct Mol Biol ; 12(10): 842-6, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16205709

RESUMO

Small heat-shock proteins (sHsps) are a widespread and diverse class of molecular chaperones. Recent evidence suggests that they maintain protein homeostasis by binding proteins in non-native conformations, thereby preventing substrate aggregation. Some members of the sHsp family are inactive or only partially active under physiological conditions, and transition toward the active state is induced by specific triggers, such as elevated temperature. Release of substrate proteins bound to sHsps requires cooperation with ATP-dependent chaperones, suggesting that sHsps create a reservoir of non-native proteins for subsequent refolding.


Assuntos
Proteínas de Choque Térmico Pequenas/química , Proteínas de Choque Térmico Pequenas/metabolismo , Proteínas de Choque Térmico Pequenas/classificação , Filogenia , Conformação Proteica , Dobramento de Proteína
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