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561.
562.
Blasig IE Winkler L Lassowski B Mueller SL Zuleger N Krause E Krause G Gast K Kolbe M Piontek J 《Cellular and molecular life sciences : CMLS》2006,63(4):505-514
Tight junctions seal intercellular clefts via membrane-related strands, hence, maintaining important organ functions. We investigated
the self-association of strand-forming transmembrane tight junction proteins. The regulatory tight junction protein occludin
was differently tagged and cotransfected in eucaryotic cells. These occludins colocalized within the plasma membrane of the
same cell, coprecipitated and exhibited fluorescence resonance energy transfer. Differently tagged strand-forming claudin-5
also colocalized in the plasma membrane of the same cell and showed fluorescence resonance energy transfer. This demonstrates
self-association in intact cells both of occludin and claudin-5 in one plasma membrane. In search of dimerizing regions of
occludin, dimerization of its cytosolic C-terminal coiledcoil domain was identified. In claudin-5, the second extracellular
loop was detected as a dimer. Since the transmembrane junctional adhesion molecule also is known to dimerize, the assumption
that homodimerization of transmembrane tight junction proteins may serve as a common structural feature in tight junction
assembly is supported.
Received 6 October 2005; received after revision 14 December 2005; accepted 27 December 2005
†These authors contributed equally to this work. 相似文献
563.
Huntington’s disease: from huntingtin function and dysfunction to therapeutic strategies 总被引:3,自引:0,他引:3
Borrell-Pagès M Zala D Humbert S Saudou F 《Cellular and molecular life sciences : CMLS》2006,63(22):2642-2660
Huntington’s disease (HD) is a neurodegenerative disorder that usually starts in middle age and is characterized by involuntary
movements (chorea), personality changes and dementia, leading to death within 10–20 years. The defective gene in HD contains
a trinucleotide CAG repeat expansion within its coding region that expresses a polyglutamine repeat in the protein huntingtin.
Together with the characteristic formation of aggregates in HD, aberrant protein interactions and several post-translational
modifications affect huntingtin during disease progression and lead to the dysfunction and death of selective neurons in the
brains of patients. The exact molecular mechanisms by which mutant huntingtin induces cell death are not completely understood
but may involve the gain of new toxic functions and the loss of the beneficial properties of huntingtin. This review focuses
on the cellular functions in which huntingtin is involved and how a better understanding of pathogenic pathways can lead to
new therapeutic approaches.
Received 24 May 2006; received after revision 5 July 2006; accepted 23 August 2006 相似文献
564.
The serine/threonine protein phosphatase 2A (PP2A) represents a large family of highly conserved heterotrimeric enzymes. Their
critical importance in cell homeostasis is underlined by the fact that they are targets of natural toxins like the tumor promoter
okadaic acid, and of simian virus 40 small tumor antigen (SV40 small t), a viral protein known to promote cell transformation.
Furthermore, mutated or lower expression levels of PP2A subunits have been found in certain cancers. One major known event
in PP2A-dependent cell transformation is the alteration of key signaling pathways that control cell growth and survival. In
this review, we focus on how PP2A enzymes also affect cell adhesion and cytoskeletal dynamics, the disruption of which is
linked to loss of cell polarity, increased cell motility and invasiveness. We also examine how those various pathways participate
in the transforming activity of SV40 small t.
Received 29 June 2006; received after revision 3 August 2006; accepted 20 September 2006 相似文献
565.
Lehmann F Tiralongo E Tiralongo J 《Cellular and molecular life sciences : CMLS》2006,63(12):1331-1354
Sialic acids consist of a family of acidic ninecarbon sugars that are typically located at the terminal positions of a variety
of glycoconjugates. Naturally occurring sialic acids show an immense diversity of structure, and this reflects their involvement
in a variety of biologically important processes. One such process involves the direct participation of sialic acids in recognition
events through specific interactions with lectins, a family of proteins that recognise and bind sugars. This review will present
a detailed overview of our current knowledge regarding the occurrence, specificity and function of sialic acid-specific lectins,
particularly those that occur in viruses, bacteria and non-vertebrate eukaryotes.
Received 13 December 2005; received after revision 9 February 2006; accepted 15 February 2006 相似文献
566.
567.
Relation between total and exchangeable sodium in the body 总被引:1,自引:0,他引:1
568.
5-Methylcytosine localised in mammalian constitutive heterochromatin 总被引:26,自引:0,他引:26
569.
Ethanol, 3 g/kg i.p., did not significantly alter the acute toxicity of amphetamine in the mouse. However, the urinary metabolite pattern was changed, suggesting that ethanol suppressed metabolism of the stimulant during the initial 6 h period. After 24 h, the mouse metabolized the same fraction of a given dose of amphetamine, whether it was given as amphetamine alone or amphetamine mixed with 2,3 or 4 g/kg ethanol. 相似文献
570.
Mark C. Hove Bernard E. Sietman Matthew S. Berg Erika C. Frost Kiru Wolf Tony R. Brady 《Journal of Natural History》2016,50(9-10):523-542
Managing a rare species can be improved with knowledge of its natural history. The sheepnose (Plethobasus cyphyus) is a freshwater mussel recently listed by the US as federally endangered. We used standard methods to study P. cyphyus brooding behaviour, host fishes in the laboratory and under natural conditions, and glochidial morphology. We monitored a population of P. cyphyus in the Chippewa River, WI during spring and summer 2007–2009 and 2011 and found brooding animals between mid-May and early August. Gravid individuals ranged between 5 and 27 yr (mean age ± 1 s.d. = 13 ± 4 yr). Plethobasus cyphyus brooded glochidia in outer gills, which varied in colour from red, orange, pink, cream, or white. We observed mature glochidia more commonly in individuals with cream or white gills and these glochidia were released in a clear, adhesive, mucus matrix. In laboratory trials we found several minnow and topminnow species (29 spp.) served as productive suitable native hosts. The mean number of juvenile mussels released per cyprinid per day was significantly higher for trials conducted at 22–25°C compared with those at 18–20°C, and 83% of trials conducted at 18–20°C using suitable host species produced no juveniles. Glochidia had a unique outline and shell morphometrics that distinguished P. cyphyus from seven other Chippewa River mussel species that produce similar sized glochidia. Using morphometrics we determined that mimic shiners (Notropis volucellus) were natural hosts for P. cyphyus, round pigtoe (Pleurobema sintoxia), and Wabash pigtoe (Fusconaia flava). Releasing mucus-bound glochidia has evolved in a variety of mussel species and may be more common than is currently realized. Our data show that P. cyphyus is a cyprinid host specialist, and propagation efforts for this species can be strengthened through improved access to mature glochidia by using females with cream-coloured gills and increased juvenile production through warmer fish holding temperatures. 相似文献