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Wyświetlanie 1-5 z 5
Tytuł:
Endoplasmic reticulum quality control and apoptosis.
Autorzy:
Groenendyk, Jody
Michalak, Marek
Powiązania:
https://bibliotekanauki.pl/articles/1041417.pdf
Data publikacji:
2005
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
intracellular organelle
molecular chaperones
endoplasmic reticulum
Opis:
The ER is one of the most important folding compartments within the cell, as well as an intracellular Ca^(2+) storage organelle and it contains a number of Ca^(2+) regulated molecular chaperones responsible for the proper folding of glycosylated as well as non-glycosylated proteins. The luminal environment of the ER contains Ca^(2+) which is involved in regulating chaperones such as calnexin and calreticulin, as well as apoptotic proteins caspase-12 and Bap31, which may play an important role in determining cellular sensitivity to ER stress and apoptosis. The ER quality control system consists of several molecular chaperones, including calnexin, that assist in properly folding proteins and transporting them through the ER as well as sensing misfolded proteins, attempting to refold them and if this is not possible, targeting them for degradation. Accumulation of misfolded protein in the ER leads to activation of genes responsible for the expression of ER chaperones. The UPR mechanism involves transcriptional activation of chaperones by the membrane-localized transcription factor ATF6, in conjunction with the ER membrane kinase IRE1, as well as translational repression of protein synthesis by another ER membrane kinase PERK. When accumulation of misfolded protein becomes toxic, apoptosis is triggered, potentially with IRE1 involved in signaling via caspase-12. Both the extrinsic and intrinsic apoptotic pathways appear to culminate in the activation of caspases and this results in the recruitment of mitochondria in an essential amplifying manner. Bap31 may direct pro-apoptotic crosstalk between the ER and the mitochondria via Ca^(2+) in conjunction with caspase-12 and calnexin. Accordingly, ER stress and the resultant Ca^(2+) release must be very carefully regulated because of their effects in virtually all areas of cell function.
Źródło:
Acta Biochimica Polonica; 2005, 52, 2; 381-395
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanizmy adaptacyjne umożliwiające życie bakterii w wysokich temperaturach
The mechanisms of adaptation allowing bacteria to survive in high temperatures
Autorzy:
Hus, Konrad
Bocian, Aleksandra
Powiązania:
https://bibliotekanauki.pl/articles/1034141.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Przyrodników im. Kopernika
Tematy:
bacteria
chaperones
thermophiles
thermostability
trehalose
bakterie
chaperony
termofile
termostabilność
trehaloza
Opis:
Z antropocentrycznego punktu widzenia, środowiska cechujące się wysokimi temperaturami opisywane są jako ekstremalne. Pierwotnie uważano, że są one zbyt niekorzystne dla rozwoju życia, jednakże wiele badań naukowych dowiodło, iż istnieje spora grupa mikroorganizmów, które mogą przetrwać w tak trudnych warunkach. Jednakże aby było to możliwe, organizmy te wykształciły wiele mechanizmów i strategii ochrony komórki przed niekorzystnymi warunkami środowiska. Zaliczyć tu można: produkcję białek szoku cieplnego, stabilizację struktury DNA, błyskawiczną resyntezę ATP, aminokwasów i innych termolabilnych składników komórki, syntezę trehalozy i innych cząsteczek stabilizujących struktury komórkowe, zwiększoną syntezę specyficznych proteaz, zastąpienie nukleotydów nikotynamidowych przez stabilniejszą ferredoksynę czy zmianę ekspresji genów w komórce. Enzymy produkowane przez mikroorganizmy termofilne są obecnie źródłem intensywnych badań, głównie ze względu na swoje wyjątkowe właściwości i szerokie zastosowanie w przemyśle.
From the anthropocentric point of view, the environments that are characterized by high temperatures have been identified as extreme ones. Originally, they were considered as too extreme to allow any organism to survive. However, later investigations have revealed that there exists a fairly large group of microorganisms thriving very well in these conditions. In order to withstand high temperatures these microorganisms have developed numerous mechanisms and strategies for protecting their cells. They include inter alia production of heat shock proteins, stabilization of the double-stranded DNA structure, rapid re-synthesis of ATP, certain amino acids and other heat-labile components of the cell, enhanced synthesis of: trehalose and other molecules stabilizing cell structures, and specific proteases hydrolyzing denatured proteins, substitution of termo-labile nicotinamide adenine dinucleotides by more thermally stable ferredoxin, as well as modifications of gene expression. Presently, enzymes produced by thermophilic microorganisms are an important area of research owing to their unique properties and wide industrial applications.
Źródło:
Kosmos; 2017, 66, 2; 175-184
0023-4249
Pojawia się w:
Kosmos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical approach to the common events in every living cell – protein folding and protein misfolding
Autorzy:
Vaibhav, V. K.
Sachin, S. L.
Powiązania:
https://bibliotekanauki.pl/articles/411778.pdf
Data publikacji:
2012
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
zwijanie białek
chaperony
zmiany konformacji molekuł białka
protein folding
protein misfolding
molecular chaperones
diseases
Opis:
Folding and unfolding are crucial ways of regulating biological activity and targeting proteins to different cellular locations. Aggregation of misfolded proteins that escape the cellular quality-control mechanisms is a common feature of a wide range of highly debilitating and increasingly prevalent diseases. Protein misfolding is a common event in living cells. Molecular chaperones not only assist protein folding; they also facilitate the degradation of misfolded polypeptides. Protein folding is governed solely by the protein itself, scientists discovered that some proteins have helped in the process called chaperones. When the intracellular degradative capacity is exceeded, juxtanuclear aggresomes are formed to sequester misfolded proteins. Misfolding of newly formed proteins not only results in a loss of physiological function of the protein but also may lead to the intra- or extra- cellular accumulation of that protein. A number of diseases have been shown to be characterised by the accumulation of misfolded proteins, notable example being Alzheimer's disease.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2012, 3; 41-51
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural basis of the interspecies interaction between the chaperone DnaK(Hsp70) and the co-chaperone GrpE of archaea and bacteria
Autorzy:
Żmijewski, Michał
Skórko-Glonek, Joanna
Tanfani, Fabio
Banecki, Bogdan
Kotlarz, Agnieszka
Macario, Alberto
Lipińska, Barbara
Powiązania:
https://bibliotekanauki.pl/articles/1041069.pdf
Data publikacji:
2007
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
substrate-binding domain
DnaK-GrpE complex
archaeal Hsp70(DnaK)
archaeal DnaK structure
molecular chaperones
ATPase domain
Opis:
Hsp70s are chaperone proteins that are conserved in evolution and present in all prokaryotic and eukaryotic organisms. In the archaea, which form a distinct kingdom, the Hsp70 chaperones have been found in some species only, including Methanosarcina mazei. Both the bacterial and archaeal Hsp70(DnaK) chaperones cooperate with a GrpE co-chaperone which stimulates the ATPase activity of the DnaK protein. It is currently believed that the archaeal Hsp70 system was obtained by the lateral transfer of chaperone genes from bacteria. Our previous finding that the DnaK and GrpE proteins of M. mazei can functionally cooperate with the Escherichia coli GrpE and DnaK supported this hypothesis. However, the cooperation was surprising, considering the very low identity of the GrpE proteins (26%) and the relatively low identity of the DnaK proteins (56%). The aim of this work was to investigate the molecular basis of the observed interspecies chaperone interaction. Infrared resolution-enhanced spectra of the M. mazei and E. coli DnaK proteins were almost identical, indicating high similarity of their secondary structures, however, some small differences in band position and in the intensity of amide I' band components were observed and discussed. Profiles of thermal denaturation of both proteins were similar, although they indicated a higher thermostability of the M. mazei DnaK compared to the E. coli DnaK. Electrophoresis under non-denaturing conditions demonstrated that purified DnaK and GrpE of E. coli and M. mazei formed mixed complexes. Protein modeling revealed high similarity of the 3-dimensional structures of the archaeal and bacterial DnaK and GrpE proteins.
Źródło:
Acta Biochimica Polonica; 2007, 54, 2; 245-252
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Plasma membrane rafts and chaperones in cytokine/ STAT signaling.
Autorzy:
Sehgal, Pravin
Powiązania:
https://bibliotekanauki.pl/articles/1043429.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
cytokine receptors
chaperones
fever
heat shock protein 90 (HSP90)
signal transducers and activators of transciption (STATs)
caveolin
lipid rafts
Opis:
We and others have recently obtained data suggesting that cytokine-STAT signaling in many different cell-types is a chaperoned pathway initiated at the level of specialized plasma membrane microdomains called "rafts" (the "raft-STAT signaling hypothesis"). These findings are of broad significance in that all cytokines and growth factors initiate signaling in target cells by interacting with respective cell-surface receptors. The new data suggest that raft microdomains represent the units of function at the cell-surface through which ligand-stimulated STAT signaling is initiated. Moreover, recent evidence shows the involvement of chaperone proteins in regulating the STAT signaling pathway. These chaperones include the human homolog of the tumorous imaginal disc 1 protein (hTid1) which associates with Janus kinase 2 (JAK2) at the level of the plasma membrane, heat shock protein 90 (HSP90) which associates with STAT3 and STAT1 proteins in caveolin-1-containing raft and cytoplasmic complexes, and glucose regulated protein 58 (GRP58/ER-60/ERp57), a thiol dependent protein-disulfide isomerase, found in association with STAT3 "statosome" complexes in the cytosol and in the raft fraction. We suggest a function of the HSP90 chaperone system in preserving IL-6/STAT3 signaling in liver cells in the context of fever. The identification and function of protein partners associated with specific STAT species in rafts and in cytosolic complexes, and in the efficient departure of cytokine-activated STATs from the cytosolic face of rafts towards the cell nucleus are now areas of active investigation.
Źródło:
Acta Biochimica Polonica; 2003, 50, 3; 583-594
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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