Search results for "Protein Precursor"
showing 10 items of 169 documents
Insertion of a malE B-Galactosidase fusion protein into the envelope of Escherichia coli disrupts biogenesis of outer membrane proteins and processin…
1982
The synthesis of a membrane-bound MalE ,B-galactosidase hybrid protein, when induced by growth of Escherichia coli on maltose, leads to inhibition of cell division and eventually a reduced rate of mass increase. In addition, the relative rate of synthesis of outer membrane proteins, but not that of inner membrane proteins, was reduced by about 50%o. Kinetic experiments demonstrated that this reduction coincided with the period of maximum synthesis of the hybrid protein (and another maltose-inducible protein, LamB). The accumulation of this abnormal protein in the envelope therefore appeared specifically to inhibit the synthesis, the assembly of outer membrane proteins, or both, indicating t…
Interactions in the network of Usher syndrome type 1 proteins
2004
International audience; Defects in myosin VIIa, harmonin (a PDZ domain protein), cadherin 23, protocadherin 15 and sans (a putative scaffolding protein), underlie five forms of Usher syndrome type I (USH1). Mouse mutants for all these proteins exhibit disorganization of their hair bundle, which is the mechanotransduction receptive structure of the inner ear sensory cells, the cochlear and vestibular hair cells. We have previously demonstrated that harmonin interacts with cadherin 23 and myosin VIIa. Here we address the extent of interactions between the five known USH1 proteins. We establish the previously suggested sans-harmonin interaction and find that sans also binds to myosin VIIa. We …
Regulation of the alpha-secretase ADAM10 by its prodomain and proprotein convertases.
2001
SPECIFIC AIMSTo identify the proprotein convertases responsible for maturation of the α-secretase ADAM10, we investigated the influence of PC7 and furin on ADAM10 processing and the resulting effect on amyloid precursor protein cleavage. We also examined the functional role of the ADAM10 prodomain by coexpression of a prodomain-deleted ADAM10 mutant together with its prodomain in trans.PRINCIPAL FINDINGS1. ADAM10 is proteolytically processed by PC7 and furinThe disintegrin metalloproteinase ADAM10 possesses α-secretase activity as well as a potential proprotein convertase recognition sequence (RKKR) after its prodomain. By amino-terminal sequencing of ADAM10 purified from bovine kidney plas…
A (1->3)-beta-D-glucan recognition protein from the sponge Suberites domuncula. Mediated activation of fibrinogen-like protein and epidermal growth f…
2004
Sponges (phylum Porifera) live in a symbiotic relationship with microorganisms, primarily bacteria. Until now, molecular proof for the capacity of sponges to recognize fungi in the surrounding aqueous milieu has not been available. Here we demonstrate, for the demosponge Suberites domuncula (Porifera, Demospongiae, Hadromerida), a cell surface receptor that recognizes (1--3)-beta-D-glucans, e.g. curdlan or laminarin. This receptor, the (1--3)-beta-D-glucan-binding protein, was identified and its cDNA analysed. The gene coding for the 45 kDa protein was found to be upregulated in tissue after incubation with carbohydrate. Simultaneously with the increased expression of this gene, two further…
The Role of the anti-amyloidogenic secretase ADAM10 in shedding the APP-like proteins.
2011
ADAM10 (A disintegrin and metalloproteinase 10) has been demonstrated as an enzyme with protective properties in Alzheimer's disease: in mouse models it not only lowered generation of toxic A-beta peptides and formation of senile plaques but also alleviated learning deficits and enhanced synaptic density. This is due to cleavage of the amyloid precursor protein (APP) within its A-beta stretch and to the release of the extracellular domain of APP with neuroprotective function. Aside from cleaving APP, ADAM10 has been linked to over 40 putative substrates at least in cell culture. These substrates are connected with important cellular functions such as cell migration, stress response and tran…
Epigenetic involvement in Hutchinson-Gilford progeria syndrome: a mini-review.
2013
Hutchinson-Gilford progeria syndrome (HGPS) is a rare human genetic disease that leads to a severe premature ageing phenotype, caused by mutations in the <i>LMNA</i> gene. The <i>LMNA</i> gene codes for lamin-A and lamin-C proteins, which are structural components of the nuclear lamina. HGPS is usually caused by a de novo <i>C1824T</i> mutation that leads to the accumulation of a dominant negative form of lamin-A called progerin. Progerin also accumulates physiologically in normal ageing cells as a rare splicing form of lamin-A transcripts. From this perspective, HGPS cells seem to be good candidates for the study of the physiological mechanisms of ageing…
Sp1 transcription factor interaction with accumulated prelamin a impairs adipose lineage differentiation in human mesenchymal stem cells: essential r…
2012
Abstract Lamin A (LMNA)-linked lipodystrophies may be either genetic (associated with LMNA mutations) or acquired (associated with the use of human immunodeficiency virus protease inhibitors [PIs]), and in both cases they share clinical features such as anomalous distribution of body fat or generalized loss of adipose tissue, metabolic alterations, and early cardiovascular complications. Both LMNA-linked lipodystrophies are characterized by the accumulation of the lamin A precursor prelamin A. The pathological mechanism by which prelamin A accumulation induces the lipodystrophy associated phenotypes remains unclear. Since the affected tissues in these disorders are of mesenchymal origin, we…
Serum inhibin A, inhibin B, pro-alphaC, and activin A levels in women with idiopathic premature ovarian failure.
2003
Serum inhibin A, inhibin B, pro-alphaC, and activin A levels in 30 women with idiopathic premature ovarian failure (POF), 30 postmenopausal women, and 30 age-matched fertile women were determined. Women with POF showed low levels of inhibin A and inhibin B, but not of activin A, whereas the levels of pro-alphaC were significantly higher than in postmenopausal women. Thus, the circulating level of pro-alphaC could be a marker for assessing residual ovarian function in women with POF.
Melatonin stimulates the nonamyloidogenic processing ofβAPP through the positive transcriptional regulation of ADAM10 and ADAM17
2014
Melatonin controls many physiological functions including regulation of the circadian rhythm and clearance of free radicals and neuroprotection. Importantly, melatonin levels strongly decrease as we age and patients with Alzheimer's disease (AD) display lower melatonin than age-matched controls. Several studies have reported that melatonin can reduce aggregation and toxicity of amyloid-β peptides that are produced from the β-amyloid precursor protein (βAPP). However, whether melatonin can directly regulate the βAPP-cleaving proteases ('secretases') has not been investigated so far. In this study, we establish that melatonin stimulates the α-secretase cleavage of βAPP in cultured neuronal an…
Physical exercise neuroprotects ovariectomized 3xTg-AD mice through BDNF mechanisms.
2014
Postmenopausal women may be more vulnerable to cognitive loss and Alzheimer's disease (AD) than premenopausal women because of their deficiency in estrogens, in addition to their usually older age. Aerobic physical exercise has been proposed as a therapeutic approach for maintaining health and well-being in postmenopausal women, and for improving brain health and plasticity in populations at high risk for AD. To study the neuroprotective mechanisms of physical exercise in a postmenopausal animal model, we submitted previously ovariectomized, six-month old non-transgenic and 3xTg-AD mice to three months of voluntary exercise in a running wheel. At nine months of age, we observed lower grip s…