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991.
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
992.
The coagulum proteins of human semen, semenogelins I and II, are secreted in abundance by the seminal vesicles. Their function
in reproduction is poorly understood as they are rapidly degraded in ejaculated semen. However, more recent results indicate
that it is time to put the semenogelins in a broader physiological perspective that goes beyond reproduction and fertility.
Received 21 June 2006; received after revision 16 August 2006; accepted 28 September 2006 相似文献
993.
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
994.
Glycogen synthase kinase 3β and Alzheimer’s disease: pathophysiological and therapeutic significance 总被引:3,自引:0,他引:3
Balaraman Y Limaye AR Levey AI Srinivasan S 《Cellular and molecular life sciences : CMLS》2006,63(11):1226-1235
Alzheimer’s disease (AD) is a neurodegenerative disorder associated with cognitive and behavioral dysfunction and is the leading
cause of dementia in the elderly. Several studies have implicated molecular and cellular signaling cascades involving the
serine-threonine kinase, glycogen synthase kinase β(GSK-3β) in the pathogenesis of AD. GSK-3β may play an important role in
the formation of neurofibrillary tangles and senile plaques, the two classical pathological hallmarks of AD. In this review,
we discuss the interaction between GSK-3β and several key molecules involved in AD, including the presenilins, amyloid precursor
protein, tau, and β-amyloid. We identify the signal transduction pathways involved in the pathogenesis of AD, including Wnt,
Notch, and the PI3 kinase/Akt pathway. These may be potential therapeutic targets in AD.
Received 19 December 2005; received after revision 24 January 2006; accepted 6 February 2006 相似文献
995.
996.
997.
Information processing along the course of a visual interneuron. 总被引:1,自引:0,他引:1
Locust ocellar retinal cells are innervated by giant second order cells, 2 mm long, which show discrete zones of integration along their course, including a major zone in the axonal length of the neuron. The complex synaptic arrangements which exist between higher-order afferent and efferent cells and these second order cells along their course suggests that transmission takes place by the electrotonic spread of slow potentials. The size and accessibility of these visual interneurons offers a unique preparation for examining mechanisms of graded synaptic transmission. 相似文献
998.
5-Methylcytosine localised in mammalian constitutive heterochromatin 总被引:26,自引:0,他引:26
999.
New Giemsa method for the differential staining of sister chromatids 总被引:127,自引:0,他引:127
1000.