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101.
Cipok M Aga-Mizrachi S Bak A Feurstein T Steinhart R Brodie C Sampson SR 《Biochemical and biophysical research communications》2006,345(2):817-824
Certain PKC isoforms are stimulated by insulin and interact with IR as well as with IRS, but it is still not clear if specific PKC isoforms regulate IR signaling directly or through IRS-1. PKCalpha may regulate IRS activity in response to insulin. We investigated the possibility that PKCalpha may be important in insulin signaling. Studies were conducted on skeletal muscle in adult mice and on L6 skeletal cells. PKCalpha is constitutively associated with IRS-1, and insulin stimulation of PKCalpha causes disassociation of the two proteins within 5 min. Blockade of PKCalpha inhibited insulin-induced disassociation of PKCalpha from IRS1. Selective inhibition of PKCalpha increased the ability of insulin to reduce blood glucose levels. Insulin stimulation activates PKB and increases the association of PKCalpha with PKB. Blockade of PKCalpha increased threonine phosphorylation of PKB. We suggest that PKCalpha regulates insulin signaling in skeletal muscle through its disassociation from IRS-1 and association with PKB. 相似文献
102.
Ní Chadhain SM Schaefer JK Crane S Zylstra GJ Barkay T 《Environmental microbiology》2006,8(10):1746-1752
The reduction of ionic mercury to elemental mercury by the mercuric reductase (MerA) enzyme plays an important role in the biogeochemical cycling of mercury in contaminated environments by partitioning mercury to the atmosphere. This activity, common in aerobic environments, has rarely been examined in anoxic sediments where production of highly toxic methylmercury occurs. Novel degenerate PCR primers were developed which span the known diversity of merA genes in Gram-negative bacteria and amplify a 285 bp fragment at the 3' end of merA. These primers were used to create a clone library and to analyse merA diversity in an anaerobic sediment enrichment collected from a mercury-contaminated site in the Meadowlands, New Jersey. A total of 174 sequences were analysed, representing 71 merA phylotypes and four novel MerA clades. This first examination of merA diversity in anoxic environments suggests an untapped resource for novel merA sequences. 相似文献
103.
A long-term record dating back to the 1960s indicates that Peridinium gatunense, an armored dinoflagellate, dominated the phytoplankton of Lake Kinneret (Sea of Galilee, Israel) until the mid-1990s, with a relatively stable spring bloom. However, since 1996, these blooms became irregular, failing to develop in 10 out of the past 16 years. During the later period, a significant correlation (R 2 = 0.605, P = 0.013) was found between annual peak P. gatunense biomass and riverine inflow volume. In-lake surveys showed that patches of high P. gatunense densities were associated with water enriched with fresher inflowing Jordan River water. Supplementing laboratory cultures of P. gatunense with Hula Valley water stimulated its growth relative to un-enriched controls. A likely explanation to the recent irregular blooms of this dinoflagellate is a hydrological modification that was made in the catchment in the mid-1990s, preventing Hula Valley water from reaching Lake Kinneret in most years—except for exceptionally wet years. We propose that until the mid-1990s, the Jordan River water enriched Lake Kinneret with a growth factor (a microelement and/or organic compound) originating in the Hula Valley, which in recent years has arrived in sufficient quantities to support a bloom only in high-rainfall years. 相似文献
104.
105.
Autophagy is an evolutionary conserved process of bulk degradation and nutrient sequestration that occurs in all eukaryotic
cells. Yet, in recent years, autophagy has also been shown to play a role in the specific degradation of individual proteins
or protein aggregates as well as of damaged organelles. The process was initially discovered in yeast and has also been very
well studied in mammals and, to a lesser extent, in plants. In this review, we summarize what is known regarding the various
functions of autopahgy in plants but also attempt to address some specific issues concerning plant autophagy, such as the
insufficient knowledge regarding autophagy in various plant species other than Arabidopsis, the fact that some genes belonging to the core autophagy machinery in various organisms are still missing in plants, the
existence of autophagy multigene families in plants and the possible operation of selective autophagy in plants, a study that
is still in its infancy. In addition, we point to plant-specific autophagy processes, such as the participation of autophagy
during development and germination of the seed, a unique plant organ. Throughout this review, we demonstrate that the use
of innovative bioinformatic resources, together with recent biological discoveries (such as the ATG8-interacting motif), should
pave the way to a more comprehensive understanding of the multiple functions of plant autophagy. 相似文献
106.
107.
Goldenberg-Cohen N Raiter A Gaydar V Dratviman-Storobinsky O Goldstein T Weizman A Hardy B 《Apoptosis : an international journal on programmed cell death》2012,17(3):278-288
Brain ischemia has major consequences leading to the apoptosis of astrocytes and neurons. Glucose-regulated protein 78 (GRP78)
known for its role in endoplasmic reticulum stress alleviation was discovered on several cell surfaces acting as a receptor
for signaling pathways. We have previously described peptides that bind cell surface GRP78 on endothelial cells to induce
angiogenesis. We have also reported that ADoPep1 binds cardiomyocytes to prevent apoptosis of ischemic heart cells. In this
study we describe the effect of hypoxia on astrocytes and neurons cell surface GRP78. Under hypoxic conditions, there was
an increase of more than fivefold in GRP78 on cell surface of neurons while astrocytes were not affected. The addition of
the GRP78 binding peptide, ADoPep1, to neurons decreased the percentage of GRP78 positive cells and did not change the percent
of astrocytes. However, a significant increase in early and late apoptosis of both astrocytes and neurons under hypoxia was
attenuated in the presence of ADoPep1. Intravitreal administration of ADoPep1 to mice in a model of optic nerve crush significantly
reduced retinal cell loss after 21 days compared to the crush-damaged eyes without treatment or by control saline vehicle
injection. Histological staining demonstrated reduced GRP78 after ADoPep1 treatment. The mechanism of peptide neuroprotection
was demonstrated by the inhibition of hypoxia induced caspase 3/7 activity, cytochrome c release and p38 phosphorylation.
This study is the first report on hypoxic neuronal and astrocyte cell surface GRP78 and suggests a potential therapeutic target
for neuroprotection. 相似文献
108.
109.
110.
Selective autophagy, mediated by Atg8 binding proteins, has not been extensively studied in plants. Plants possess a large gene family encoding multiple isoforms of the Atg8 protein. We have recently reported the identification of two new, closely homologous Arabidopsis thaliana plant proteins that bind the Arabidopsis Atg8f protein isoform. These two proteins are specific to plants and have no homologs in nonplant organisms. The expression levels of the genes encoding these proteins are elevated during carbon starvation and also during late stages of seed development. Exposure of young seedlings to carbon starvation induces the production of a newly identified compartment decorated by these Atg8-binding proteins. This compartment dynamically moves along the endoplasmic reticulum membrane and is also finally transported into the vacuole. Enhanced or suppressed expression of these Atg8-binding proteins respectively enhances or suppresses seed germination under suboptimal germination conditions, indicating that they contribute to seed germination vigor. 相似文献