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981.
A. Shukla P. Chaurasia S. R. Bhaumik 《Cellular and molecular life sciences : CMLS》2009,66(8):1419-1433
Methylation of lysine residues of histones is associated with functionally distinct regions of chromatin, and, therefore,
is an important epigenetic mark. Over the past few years, several enzymes that catalyze this covalent modification on different
lysine residues of histones have been discovered. Intriguingly, histone lysine methylation has also been shown to be cross-regulated
by histone ubiquitination or the enzymes that catalyze this modification. These covalent modifications and their cross-talks
play important roles in regulation of gene expression, heterochromatin formation, genome stability, and cancer. Thus, there
has been a very rapid progress within past several years towards elucidating the molecular basis of histone lysine methylation
and ubiquitination, and their aberrations in human diseases. Here, we discuss these covalent modifications with their cross-regulation
and roles in controlling gene expression and stability.
Received 24 September 2008; received after revision 21 November 2008; accepted 28 November 2008 相似文献
982.
V. Le Fourn K. Gaplovska-Kysela B. Guhl R. Santimaria C. Zuber J. Roth 《Cellular and molecular life sciences : CMLS》2009,66(8):1434-1445
Little is known about the fate of machinery proteins of the protein quality control and endoplasmic reticulum(ER)-associated
degradation (ERAD). We investigated the degradation of the ERAD component EDEM1, which directs overexpressed misfolded glycoproteins
to degradation. Endogenous EDEM1 was studied since EDEM1 overexpression not only resulted in inappropriate occurrence throughout
the ER but also caused cytotoxic effects. Proteasome inhibitors had no effect on the clearance of endogenous EDEM1 in non-starved
cells. However, EDEM1 could be detected by immunocytochemistry in autophagosomes and biochemically in LC3 immuno-purified
autophagosomes. Furthermore, influencing the lysosome-autophagy pathway by vinblastine or pepstatin A/E64d and inhibiting
autophagosome formation by 3-methyladenine or ATGs short interfering RNA knockdown stabilized EDEM1. Autophagic degradation
involved removal of cytosolic Triton X-100-insoluble deglycosylated EDEM1, but not of EDEM1-containing ER cisternae. Our studies
demonstrate that endogenous EDEM1 in cells not stressed by the expression of a transgenic misfolded protein reaches the cytosol
and is degraded by basal autophagy.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Received 15 January 2009; received after revision 16 February 2009; accepted 17 February 2009
V. Le Fourn, K. Gaplovska-Kysela: These authors equally contributed to this work. 相似文献
983.
C. Schubert 《Cellular and molecular life sciences : CMLS》2009,66(7):1178-1197
The Williams-Beuren syndrome is a genomic disorder (prevalence: 1/7,500 to 1/20,000), caused by a hemizygous contiguous gene
deletion on chromosome 7q11.23. Typical symptoms comprise supravalvular aortic stenosis, mental retardation, overfriendliness
and visuospatial impairment. The common deletion sizes range of 1.5–1.8 mega base pairs (Mb), encompassing app. 28 genes.
For a few genes, a genotype-phenotype correlation has been established. The best-explored gene within this region is the elastin
gene; its haploinsufficiency causes arterial stenosis. The region of the Williams-Beuren syndrome consists of a single copy
gene region (~1.2 Mb) flanked by repetitive sequences – Low Copy Repeats (LCR). The deletions arise as a consequence of misalignment
of these repetitive sequences during meiosis and a following unequal crossing over due to high similarity of LCRs. This review
presents an overview of the Williams-Beuren syndrome region considering the genomic assembly, chromosomal rearrangements and
their mechanisms (i.e. deletions, duplications, inversions) and evolutionary and historical aspects.
Received 11 July 2008; received after revision 15 October 2008; accepted 16 October 2008 相似文献
984.
The elucidation of assembly pathways of multi-subunit membrane proteins is of growing interest in structural biology. In this
study, we provide an analysis of the assembly of the asymmetrically oriented PsaC subunit on the pseudo C2-symmetric Photosystem I core. Based on a comparison of the differences in the NMR solution structure of unbound PsaC with
that of the X-ray crystal structure of bound PsaC, and on a detailed analysis of the PsaC binding site surrounding the FX iron-sulfur cluster, two models can be envisioned for what are likely the last steps in the assembly of Photosystem I. Here,
we dissect both models and attempt to address heretofore unrecognized issues by proposing a mechanism that includes a thermodynamic
perspective. Experimental strategies to verify the models are proposed. In closing, the evolutionary aspects of the assembly
process will be considered, with special reference to the structural arrangement of the PsaC binding surface.
Received 22 October 2008; received after revision 17 November 2008; accepted 05 December 2008 相似文献
985.
Berger W Steiner E Grusch M Elbling L Micksche M 《Cellular and molecular life sciences : CMLS》2009,66(1):43-61
The unique and evolutionary highly conserved major vault protein (MVP) is the main component of ubiquitous, large cellular
ribonucleoparticles termed vaults. The 100 kDa MVP represents more than 70% of the vault mass which contains two additional
proteins, the vault poly (ADP-ribose) polymerase (vPARP) and the telomerase-associated protein 1 (TEP1), as well as several
short untranslated RNAs (vRNA). Vaults are almost ubiquitously expressed and, besides chemotherapy resistance, have been implicated
in the regulation of several cellular processes including transport mechanisms, signal transmissions and immune responses.
Despite a growing amount of data from diverse species and systems, the definition of precise vault functions is still highly
complex and challenging. Here we review the current knowledge on MVP and vaults with focus on regulatory functions in intracellular
signal transduction and immune defence.
Received 27 June 2008; received after revision 25 July 2008; accepted 30 July 2008 相似文献
986.
Dirk M. Walther Doron Rapaport Jan Tommassen 《Cellular and molecular life sciences : CMLS》2009,66(17):2789-2804
Membrane-embedded β-barrel proteins span the membrane via multiple amphipathic β-strands arranged in a cylindrical shape.
These proteins are found in the outer membranes of Gram-negative bacteria, mitochondria and chloroplasts. This situation is
thought to reflect the evolutionary origin of mitochondria and chloroplasts from Gram-negative bacterial endosymbionts. β-barrel
proteins fulfil a variety of functions; among them are pore-forming proteins that allow the flux of metabolites across the
membrane by passive diffusion, active transporters of siderophores, enzymes, structural proteins, and proteins that mediate
protein translocation across or insertion into membranes. The biogenesis process of these proteins combines evolutionary conservation
of the central elements with some noticeable differences in signals and machineries. This review summarizes our current knowledge
of the functions and biogenesis of this special family of proteins. 相似文献
987.
S. Kjellev 《Cellular and molecular life sciences : CMLS》2009,66(8):1350-1369
The trefoil factor family (TFF) comprises a group of small peptides which are highly expressed in tissues containing mucus-producing
cells – especially in the mucosa lining the gastrointestinal tract. The peptides seem crucial for epithelial restitution and
may work via other pathways than the conventional factors involved in restitution. In vitro studies have shown that the TFFs promote restitution using multiple mechanisms. The peptides also have other functionalities
including interactions with the immune system. Moreover, therapeutic effects of the TFFs have been shown in several animal
models of gastrointestinal damage. Still it is not clear which of their in vitro properties are involved in the in vivo mode of action. This review describes the TFF family with emphasis on their biological properties and involvement in mucosal
protection and repair.
Received 10 October 2008; received after revision 07 November 2008; accepted 10 November 2008 相似文献
988.
A latent ability to persist: differentiation in <Emphasis Type="Italic">Toxoplasma gondii</Emphasis>
Victoria Jeffers Zoi Tampaki Kami Kim William J. SullivanJr. 《Cellular and molecular life sciences : CMLS》2018,75(13):2355-2373
A critical factor in the transmission and pathogenesis of Toxoplasma gondii is the ability to convert from an acute disease-causing, proliferative stage (tachyzoite), to a chronic, dormant stage (bradyzoite). The conversion of the tachyzoite-containing parasitophorous vacuole membrane into the less permeable bradyzoite cyst wall allows the parasite to persist for years within the host to maximize transmissibility to both primary (felids) and secondary (virtually all other warm-blooded vertebrates) hosts. This review presents our current understanding of the latent stage, including the factors that are important in bradyzoite induction and maintenance. Also discussed are the recent studies that have begun to unravel the mechanisms behind stage switching. 相似文献
989.
Microbial model systems have a long history of fruitful use in fields that include evolution and ecology. In order to develop further insight into modelling practice, we examine how the competitive exclusion and coexistence of competing species have been modelled mathematically and materially over the course of a long research history. In particular, we investigate how microbial models of these dynamics interact with mathematical or computational models of the same phenomena. Our cases illuminate the ways in which microbial systems and equations work as models, and what happens when they generate inconsistent findings about shared targets. We reveal an iterative strategy of comparative modelling in different media, and suggest reasons why microbial models have a special degree of epistemic tractability in multimodel inquiry. 相似文献
990.
J. D. Trout has recently developed a new defense of scientific realism, a new version of the No Miracles Argument. I critically evaluate Trout's novel defense of realism. I argue that Trout's argument for scientific realism and the related explanation for the success of science are self-defeating. In the process of arguing against the traditional realist strategies for explaining the success of science, he inadvertently undermines his own argument. 相似文献