共查询到20条相似文献,搜索用时 31 毫秒
1.
Jägerbrink T Lexander H Palmberg C Shafqat J Sharoyko V Berggren PO Efendic S Zaitsev S Jörnvall H 《Cellular and molecular life sciences : CMLS》2007,64(10):1310-1316
The effects of an imidazoline compound (BL11282) on protein expression in rat pancreatic islets were investigated with a proteomic
approach. The compound increases insulin release selectively at high glucose concentrations and is therefore of interest in
type 2 diabetes. Whole cell extracts from isolated drug-treated and native pancreatic rat islets were compared after separation
by 2-D gel electrophoresis. Differentially expressed proteins were identified by mass spectrometry; 15 proteins were selectively
up-regulated and 7 selectively down-regulated in drug-treated islets. Of special interest among the differentially expressed
proteins are those involved in protein folding (Hsp60, protein disulfide isomerase, calreticulin), Ca2+ binding (calgizzarin, calcyclin and annexin I) and metabolism or signalling (pyruvate kinase, alpha enolase and protein kinase
C inhibitor 1).
Received 19 March 2007; received after revision 11 April 2007; accepted 11 April 2007 相似文献
2.
Hurtaud C Gelly C Chen Z Lévi-Meyrueis C Bouillaud F 《Cellular and molecular life sciences : CMLS》2007,64(14):1853-1860
Uncoupling protein 2 (UCP2) belongs to a family of transporters/exchangers of the mitochondrial inner membrane. Using cell
lines representing natural sites of UCP2 expression (macrophages, colonocytes, pancreatic beta cells), we show that UCP2 expression
is stimulated by glutamine at physiological concentrations. This control is exerted at the translational level. We demonstrate
that the upstream open reading frame (ORF1) in the 5’ untranslated region (5’UTR) of the UCP2 mRNA is required for this stimulation
to take place. Cloning of the 5’ UTR of the UCP2 mRNA in front of a GFP cDNA resulted in a reporter gene with which GFP expression
could be induced by glutamine. An effect of glutamine on translation of a given mRNA has not been identified before, and this
is the first evidence for a link between UCP2 and glutamine, an amino acid oxidized by immune cells or intestinal epithelium
and playing a role in the control of insulin secretion.
Received 26 January 2007; received after revision 16 April 2007; accepted 8 May 2007
C. Hurtaud, C. Gelly: These authors contributed equally to this work. 相似文献
3.
de Keyzer J van der Does C Driessen AJ 《Cellular and molecular life sciences : CMLS》2003,60(10):2034-2052
The major route of protein translocation in bacteria is the so-called general secretion pathway (Sec-pathway). This route has been extensively studied in Escherichia coli and other bacteria. The movement of preproteins across the cytoplasmic membrane is mediated by a multimeric membrane protein complex called translocase. The core of the translocase consists of a proteinaceous channel formed by an oligomeric assembly of the heterotrimeric membrane protein complex SecYEG and the peripheral adenosine triphosphatase (ATPase) SecA as molecular motor. Many secretory proteins utilize the molecular chaperone SecB for targeting and stabilization of the unfolded state prior to translocation, while most nascent inner membrane proteins are targeted to the translocase by the signal recognition particle and its membrane receptor. Translocation is driven by ATP hydrolysis and the proton motive force. In the last decade, genetic and biochemical studies have provided detailed insights into the mechanism of preprotein translocation. Recent crystallographic studies on SecA, SecB and the SecYEG complex now provide knowledge about the structural features of the translocation process. Here, we will discuss the mechanistic and structural basis of the translocation of proteins across and the integration of membrane proteins into the cytoplasmic membrane.Received 10 January 2003; received after revision 2 April 2003; accepted 4 April 2003 相似文献
4.
Myelin basic protein: a multifunctional protein 总被引:1,自引:1,他引:0
Boggs JM 《Cellular and molecular life sciences : CMLS》2006,63(17):1945-1961
Myelin basic protein (MBP), the second most abundant protein in central nervous system myelin, is responsible for adhesion
of the cytosolic surfaces of multilayered compact myelin. A member of the ‘intrinsically disordered’ or conformationally adaptable
protein family, it also appears to have several other functions. It can interact with a number of polyanionic proteins including
actin, tubulin, Ca2+-calmodulin, and clathrin, and negatively charged lipids, and acquires structure on binding to them. It may act as a membrane
actin-binding protein, which might allow it to participate in transmission of extracellular signals to the cytoskeleton in
oligodendrocytes and tight junctions in myelin. Some size isoforms of MBP are transported into the nucleus and thus they may
also bind polynucleotides. Extracellular signals received by myelin or cultured oligodendrocytes cause changes in phosphorylation
of MBP, suggesting that MBP is also involved in signaling. Further study of this very abundant protein will reveal how it
is utilized by the oligodendrocyte and myelin for different purposes.
Received 2 March 2006; received after revision 12 April 2006; accepted 16 May 2006 相似文献
5.
Modulation of protein biophysical properties by chemical glycosylation: biochemical insights and biomedical implications 总被引:2,自引:0,他引:2
Solá RJ Rodríguez-Martínez JA Griebenow K 《Cellular and molecular life sciences : CMLS》2007,64(16):2133-2152
Glycosylation constitutes one of the most important posttranslational modifications employed by biological systems to modulate
protein biophysical properties. Due to the direct biochemical and biomedical implications of achieving control over protein
stability and function by chemical means, there has been great interest in recent years towards the development of chemical
strategies for protein glycosylation. Since current knowledge about glycoprotein biophysics has been mainly derived from the
study of naturally glycosylated proteins, chemical glycosylation provides novel insights into its mechanistic understanding
by affording control over glycosylation parameters. This review presents a survey of the effects that natural and chemical
glycosylation have on the fundamental biophysical properties of proteins (structure, dynamics, stability, and function). This
is complemented by a mechanistic discussion of how glycans achieve such effects and discussion of the implications of employing
chemical glycosylation as a tool to exert control over protein biophysical properties within biochemical and biomedical applications.
Received 15 December 2006; received after revision 28 March 2007; accepted 25 April 2007 相似文献
6.
Olfactory ensheathing cells have been used in several studies to promote repair in the injured spinal cord. However, cellular
interaction between olfactory ensheathing cells and glial cells induced to be reactive in the aftermath of injury site has
not been investigated. Using an in vitro model of astrogliosis, we show that reactive astrocytes expressed significantly less glial fibrillary acidic protein (GFAP)
when cultured both in direct contact with olfactory ensheathing cells and when the two cell types were separated by a porous
membrane. Immunofluorescence staining also suggested that reactive astrocytes showed decreased chondroitin sulfate proteoglycans
in the presence of olfactory ensheathing cells, although the reduction was not statistically significant. No down-regulation
of GFAP was observed when reactive astrocytes were similarly cultured with Schwann cells. Cell viability assay and bromodeoxyuridine
uptake showed that proliferation of reactive astrocytes was significantly increased in the presence of olfactory ensheathing
cells and Schwann cells.
Received 27 February 2007; received after revision 30 March 2007; accepted 3 April 2007 相似文献
7.
Navarro S Aleu J Jiménez M Boix E Cuchillo CM Nogués MV 《Cellular and molecular life sciences : CMLS》2008,65(2):324-337
Human eosinophil cationic protein (ECP)/ ribonuclease 3 (RNase 3) is a protein secreted from the secondary granules of activated
eosinophils. Specific properties of ECP contribute to its cytotoxic activities associated with defense mechanisms. In this
work the ECP cytotoxic activity on eukaryotic cell lines is analyzed. The ECP effects begin with its binding and aggregation
to the cell surface, altering the cell membrane permeability and modifying the cell ionic equilibrium. No internalization
of the protein is observed. These signals induce cell-specific morphological and biochemical changes such as chromatin condensation,
reversion of membrane asymmetry, reactive oxygen species production and activation of caspase-3-like activity and, eventually,
cell death. However, the ribonuclease activity component of ECP is not involved in this process as no RNA degradation is observed.
In summary, the cytotoxic effect of ECP is attained through a mechanism different from that of other cytotoxic RNases and
may be related with the ECP accumulation associated with the inflammatory processes, in which eosinophils are present.
Received 26 October 2007; accepted 23 November 2007 相似文献
8.
The investigation of biological macromolecules and the characteristics that determine their function has been of particular
interest over the last decades. Here we overview some modern approaches for making the most of the 3-D protein structural
information, with a distinctive emphasis on macromolecular crystallography and complementary techniques used to establish
the structure-function relationship. A tight link between the biology of the cellular processes and the underlying chemistry
of protein function governs the flow of the presented material. The reader will be lead through the basic principles of protein
structure analysis and the means to capture the characteristics that portray the function. The techniques exploiting high-resolution
data and allowing quantification of molecular motion and structure-activity relationship are given particular attention.
Received 20 April 2007; accepted 20 April 2007 相似文献
9.
Gap junctions (GJs) are composed of proteins that form a channel connecting the cytoplasm of adjacent cells. Connexins were
initially considered to be the only proteins capable of GJ formation. Another family of GJ proteins (innexins) were first
found in invertebrates and were proposed to be renamed pannexins after their orthologs were discovered in vertebrates. The
lack of both connexins and pannexins in the genomes of some metazoans suggests that other, still undiscovered GJ proteins
exist. In vertebrates, connexins and pannexins co-exist. Here we discuss whether vertebrate pannexins have a nonredundant
role in animal physiology. Pannexin channels appear to be suited for ATP and calcium signaling and play a role in the maintenance
of calcium homeostasis by mechanisms implicating both GJ and nonjunctional function. Suggested roles in the ischemic death
of neurons, schizophrenia, inflammation and tumor suppression have drawn much attention to exploring the molecular properties
and cellular functions of pannexins.
Received 22 April 2007; received after revision 9 September 2007; accepted 19 September 2007 相似文献
10.
Morrison BE Majdzadeh N D'Mello SR 《Cellular and molecular life sciences : CMLS》2007,64(17):2258-2269
Neurodegenerative disease strikes millions worldwide and there is mounting evidence suggesting that underlying the onset and
progression of these debilitating diseases is inappropriate neuronal apoptosis. Recent reports have implicated a family of
proteins known as histone deacetylases (HDACs) in various neuronal processes including the neuronal death program. Initial
headway in this field has been made largely through the use of broad-spectrum HDAC inhibitors. In fact, pharmacological inhibition
of HDAC activity has been shown to protect neurons in several models of neurodegeneration. The observation that HDAC inhibitors
can have opposing effects in different paradigms of neurodegeneration suggests that individual members of the HDAC protein
family may play distinct roles that could depend on the specific cell type under study. The purpose of this review is to detail
work involving the use of HDAC inhibitors within the context of neurodegeneration and examine the roles of individual HDAC
members in the nervous system with specific focus on neuronal cell death.
Received 25 January 2007; received after revision 3 April 2007; accepted 26 April 2007 相似文献
11.
Gbaguidi B Hakizimana P Vandenbussche G Ruysschaert JM 《Cellular and molecular life sciences : CMLS》2007,64(12):1571-1582
LmrP is an electrogenic H+/drug antiporter that extrudes a broad spectrum of antibiotics. Five carboxylic residues are implicated in drug binding (Asp142
and Glu327) and proton motive force-mediated restructuring (Asp68, Asp128 and Asp235). ATR-FTIR (Attenuated Total Reflection
– Fourier Transform Infrared) and tryptophan quenching experiments revealed that phosphatidylethanolamine (PE) is required
to generate the structural intermediates induced by ionization of carboxylic residues. Surprisingly, no ionization-induced
conformational changes were detectable in the absence of PE, suggesting either that carboxylic acid residues do not ionize
or that ionization does not lead to any conformational change. The mean pKa of carboxylic residues evaluated by ATR-FTIR spectroscopy
was 6.5 for LmrP reconstituted in PE liposomes, whereas the pKa calculated in the absence of PE was 4.6. Considering that
16 of the 19 carboxylic residues are located in the extramembrane loops, the pKa values obtained in the absence and in the
presence of PE suggest that the interaction of the loop acid residues with the membrane interface depends on the lipid composition.
Received 23 January 2007; received after revision 2 April 2007; accepted 20 April 2007 相似文献
12.
Retinal proteins function as photoreceptors and ion pumps. Xanthorhodopsin of Salinibacter ruber is a recent addition to this diverse family. Its novel and distinctive feature is a second chromophore, a carotenoid, which
serves as light-harvesting antenna. Here we discuss the properties of this carotenoid/retinal complex most relevant to its
function (such as the specific binding site controlled by the retinal) and its relationship to other retinal proteins (bacteriorhodopsin,
archaerhodopsin, proteorhodopsin and retinal photoreceptors of archaea and eukaryotes). Antenna addition to a retinal protein
has not been observed among the archaea and emerged in bacteria apparently in response to environmental conditions where light-harvesting
becomes a limiting factor in retinal protein functioning.
Received 2 April 2007; received after revision 14 May 2007; accepted 16 May 2007 相似文献
13.
In recent years the interest in antimicrobial proteins and peptides and their mode of action has been rapidly increasing due
to their potential to prevent and combat microbial infections in all areas of life. A detailed knowledge about the function
of such proteins is the most important requirement to consider them for future application. Our research in recent years has
been focused on the low molecular weight, cysteine-rich and cationic antifungal protein PAF from Penicillium chrysogenum, which inhibits the growth of opportunistic zoo-pathogens including Aspergillus fumigatus, numerous plant-pathogenic fungi and the model organism Aspergillus nidulans. So far, the experimental results indicate that PAF elicits hyperpolarization of the plasma membrane and the activation of
ion channels, followed by an increase in reactive oxygen species in the cell and the induction of an apoptosis-like phenotype.
Detailed knowledge about the molecular mechanism of action of antifungal proteins such as PAF contributes to the development
of new antimicrobial strategies that are urgently needed.
Received 09 August 2007; received after revision 17 September 2007; accepted 19 September 2007 相似文献
14.
Mass spectrometry for protein and peptide characterisation 总被引:5,自引:0,他引:5
Jonsson AP 《Cellular and molecular life sciences : CMLS》2001,58(7):868-884
Mass spectrometry has become an important analytical tool in biological and biochemical research. Its speed, accuracy and
sensitivity are unmatched by conventional analytical techniques. Identification of proteins and characterisation of their
primary structure is a rapidly growing field in the post-genomic era, where matrix-assisted laser desorption/ionisation time-of-flight
peptide mass fingerprinting combined with electrospray tandem mass spectrometry can efficiently solve many questions. Many
recently determined genomic sequences have not been characterised at the protein level. Analysis of the amino acid sequence
and characterisation of post-translational modifications are therefore important steps towards correlation of protein structure
with function. This review concerns methods, instrumentation and applications of mass spectrometry in protein and peptide
analysis.
Received 17 April 2001; accepted 19 April 2001 相似文献
15.
The polypyrimidine tract binding protein (PTB) is a 58-kDa RNA binding protein involved in multiple aspects of mRNA metabolism
including splicing regulation, polyadenylation, 3′end formation, internal ribosomal entry site-mediated translation, RNA localization
and stability. PTB contains four RNA recognition motifs (RRMs) separated by three linkers. In this review we summarize structural
information on PTB in solution that has been gathered during the past 7 years using NMR spectroscopy and small-angle X-ray
scattering. The structures of all RRMs of PTB in their free state and in complex with short pyrimidine tracts, as well as
a structural model of PTB RRM2 in complex with a peptide, revealed unusual structural features that provided new insights
into the mechanisms of action of PTB in the different processes of RNA metabolism and in particular splicing regulation.
Received 16 August 2007; received after revision 18 September 2007; accepted 2 October 2007 相似文献
16.
Hunt MC Greene S Hultenby K Svensson LT Engberg S Alexson SE 《Cellular and molecular life sciences : CMLS》2007,64(12):1558-1570
Acyl-CoA thioesterases (ACOTs) catalyze the hydrolysis of acyl-CoAs to free fatty acids and coenzyme A. Recent studies have
demonstrated that one gene named Acot7, reported to be mainly expressed in brain and testis, is transcribed in several different isoforms by alternative usage of
first exons. Strongly decreased levels of ACOT7 activity and protein in both mitochondria and cytosol was reported in patients
diagnosed with fatty acid oxidation defects, linking ACOT7 function to regulation of fatty acid oxidation in other tissues.
In this study, we have identified five possible first exons in mouse Acot7 (Acot7a–e) and show that all five first exons are transcribed in a tissue-specific manner. Taken together, these data show that the
Acot7 gene is expressed as multiple isoforms in a tissue-specific manner, and that expression in tissues other than brain and testis
is likely to play important roles in fatty acid metabolism.
Received 5 February 2007: received after revision 3 April 2007; accepted 19 April 2007 相似文献
17.
Liu ZM Chen GG Vlantis AC Tse GM Shum CK van Hasselt CA 《Cellular and molecular life sciences : CMLS》2007,64(11):1428-1436
The molecular mechanism responsible for cadmium-induced cell death in thyroid cancer cells (FRO) is unknown. We demonstrated
that apoptosis of FRO cells induced by cadmium was concentration and time dependent. Cadmium caused the rapid elevation of
intracellular calcium and induced phosphorylation of Akt, p53, JNK, ERK and p38. Inhibition of PI3K/Akt attenuated the cadmium-induced
apoptosis, but the inhibition of JNK inhibitor, ERK or p38 aggravated it, indicating that activation of PI3K/Akt was a pro-apoptosis
signal in response to cadmium treatment, whereas the activation of stress-activated protein kinase JNK, ERK and p38 functioned
as survival signals to counteract the cadmium-induced apoptosis. Buffering of the calcium response attenuated mitochondrial
impairment, recovered the cadmium-activated Akt, p53, JNK, ERK and p38, and subsequently blocked the apoptosis. These results
suggested that apoptosis induced by cadmium in FRO cells was initiated by the rapid elevation of intracellular calcium, followed
by calcium-mediated activation of PI3K/Akt and mitochondrial impairment.
Received 28 February 2007; received after revision 2 April 2007; accepted 23 April 2007 相似文献
18.
Sokolowska M Kaus-Drobek M Czapinska H Tamulaitis G Siksnys V Bochtler M 《Cellular and molecular life sciences : CMLS》2007,64(18):2351-2357
It has long been known that most Type II restriction endonucleases share a conserved core fold and similar active-sites. The
same core folding motif is also present in the MutH protein, a component of the bacterial DNA mismatch repair machinery. In
contrast to most Type II restriction endonucleases, which assemble into functional dimers and catalyze double-strand breaks,
MutH is a monomer and nicks hemimethylated DNA. Recent biochemical and crystallographic studies demonstrate that the restriction
enzymes BcnI and MvaI share many additional features with MutH-like proteins, but not with most other restriction endonucleases.
The structurally similar monomers all recognize approximately symmetric target sequences asymmetrically. Differential sensitivities
to slight substrate asymmetries, which could be altered by protein engineering, determine whether the enzymes catalyze only
single-strand nicks or double-strand breaks.
M. Sokolowska, M. Kaus-Drobek: These authors contributed equally to this work.
Received 12 March 2007; received after revision 28 April 2007; accepted 3 May 2007 相似文献
19.
The plasma membrane of epithelial cells and hepatocytes is divided into two separate membrane compartments, the apical and
the basolateral domain. This polarity is maintained by intracellular machinery that directs newly synthesized material into
the correct target membrane. Apical protein sorting and trafficking require specific signals and different intracellular routes
to the cell surface. Some of them depend on the integrity of sphingolipid/cholesterol-enriched membrane microdomains named
‘lipid rafts’, others use separate transport platforms. Certain characteristics of the heterogeneous population of apical
sorting signals are described in this review and cellular factors associated with sorting and transport mechanisms are discussed.
Received 5 May 2006; received after revision 12 June 2006; accepted 11 July 2006 相似文献
20.
Various adenosine triphosphate (ATP)-dependent proteases were identified within mitochondria which mediate selective mitochondrial protein degradation and fulfill crucial functions in mitochondrial biogenesis. The matrix-localized PIM1 protease, a homologue of theEscherichia coli Lon protease, is required for respiration and maintenance of mitochondrial genome integrity. Degradation of non-native polypeptides by PIM1 protease depends on the chaperone activity of the mitochondrial Hsp70 system, posing intriguing questions about the relation between the proteolytic system and the folding machinery in mitochondria. The mitochondrial inner membrane harbors two ATP-dependent metallopeptidases, them- and thei-AAA protease, which expose their catalytic sites to opposite membrane surfaces and cooperate in the degradation of inner membrane proteins. In addition to its proteolytic activity, them-AAA protease has chaperone-like activity during the assembly of respiratory and ATP-synthase complexes. It constitutes a quality control system in the inner membrane for membrane-embedded protein complexes. 相似文献