Search results for "calpain"

Phosphodiesterase inhibition induces retinal degeneration, oxidative stress and inflammation in cone-enriched cultures of porcine retina.

2013

nherited retinal degenerations affecting both rod and cone photoreceptors constitute one of the causes 74 of incurable blindness in the developed world. Cyclic guanosine monophosphate (cGMP) is crucial in the 75 phototransduction and, mutations in genes related to its metabolism are responsible for different retinal 76 dystrophies. cGMP-degrading phosphodiesterase 6 (PDE6) mutations cause around 4e5% of the retinitis 77 pigmentosa, a rare form of retinal degeneration. The aim of this study was to evaluate whether phar- 78 macological PDE6 inhibition induced retinal degeneration in cone-enriched cultures of porcine retina 79 similar to that found in murine models. PDE6 inhibition was induced…

Expression of calpain-calpastatin system (CCS) member proteins in human lymphocytes of young and elderly individuals; pilot baseline data for the CAL…

2013

Abstract Background Ubiquitous system of regulatory, calcium-dependent, cytoplasmic proteases – calpains – and their endogenous inhibitor – calpastatin – is implicated in the proteolytic regulation of activation, proliferation, and apoptosis of many cell types. However, it has not been thoroughly studied in resting and activated human lymphocytes yet, especially in relation to the subjects’ ageing process. The CALPACENT project is an international (Polish-Italian) project aiming at verifying the hypothesis of the role of calpains in the function of peripheral blood immune cells of Polish (Pomeranian) and Italian (Sicilian) centenarians, apparently relatively preserved in comparison to the g…

Protective effect of paraoxonase-2 against endoplasmic reticulum stress-induced apoptosis is lost upon disturbance of calcium homoeostasis

2008

PON2 (paraoxonase-2) is a ubiquitously expressed antioxidative protein which is largely found in the ER (endoplasmic reticulum). Addressing the cytoprotective functions of PON2, we observed that PON2 overexpression provided significant resistance to ER-stress-induced caspase 3 activation when the ER stress was induced by interference with protein modification (by tunicamycin or dithiothreitol), but not when ER stress was induced by disturbance of Ca2+ homoeostasis (by thapsigargin or A23187). When analysing the underlying molecular events, we found an activation of the PON2 promoter in response to all tested ER-stress-inducing stimuli. However, only tunicamycin and dithiothreitol resulted i…

Subcellular distribution of calpain-1 and calpain-2 as a key event for calpain-mediated functions in physiological and neoplastic mammary models

2019

Calpains are a family of calcium-dependent proteases, which modulate their substrates rather than degrade them in such a way that modifies them. Calpains deregulations have been determined as an aggravating factor of different diseases, including cancer. Nevertheless, there are no clear records about the particular contribution of each calpain isoform in physiological processes and how these isoforms are deregulated in pathological conditions. In vivo, each calpain isoform recognizes specific proteins as substrates, and it has been suggested that calpains subcellular localization might determine their substrate recognition, and consequently their functions. In the present study we have expl…

Type V collagen-induced upregulation of capn2 (large subunit of m-calpain) gene expression and DNA fragmentation in 8701-BC breast cancer cells

2011

Abstract Type V collagen is known to be over-deposited in the stroma of ductal infiltrating carcinomas of the breast. When used as a substrate, type V collagen restrains growth and invasion, and affects gene expression of 8701-BC ductal infiltrating carcinomas cells. Here we supplement existing data by demonstrating type V collagen dependent upregulation of capn2 gene expression in 8701-BC cells through differential display-PCR and Western blot assays. Furthermore, we suggest that our data obtained by centrifugal sedimentation and electrophoresis strongly suggest a correlation between calpain overproduction and DNA fragmentation, since the incubation with calpain inhibitor partly reverts th…

Clustering-triggered endocytic pathway of α2β1 integrin

2012

Secondary reduction in calpain 3 expression in patients with limb girdle muscular dystrophy type 2B and Miyoshi myopathy (primary dysferlinopathies).

2000

Made available in DSpace on 2016-10-10T03:52:18Z (GMT). No. of bitstreams: 5 Secondary reduction in calpain 3 expression in patients with limb girdle muscular dystrophy type 2B and Miyoshi myopathy.pdf: 167085 bytes, checksum: b445ec059ea2d0f06bd4fa913354872a (MD5) license_url: 52 bytes, checksum: 2f32edb9c19a57e928372a33fd08dba5 (MD5) license_text: 24259 bytes, checksum: f1f24f769b03eb8f9cd3f53c1090841c (MD5) license_rdf: 24658 bytes, checksum: 9d3847733d3c0b59c7c89a1d40d3d240 (MD5) license.txt: 1887 bytes, checksum: 445d1980f282ec865917de35a4c622f6 (MD5) Previous issue date: 2000 Dysferlin is the protein product of the gene (DYSF) that is defective in patients with limb girdle muscular dy…

Oestrogen receptor subtype-specific repression of calpain expression and calpain enzymatic activity in neuronal cells - implications for neuroprotect…

2006

Calpains represent a superfamily of Ca2+-activated cysteine-proteases, which are important mediators of apoptosis and necrosis. In the brain, m-calpain and micro-calpain, the two ubiquitous calpain-isoforms, are strongly activated in neurones after an excitotoxic Ca2+ influx occurring, for example, during cerebral ischemia. Because oestrogen and its receptors (ERalpha/ERbeta) can exert neuroprotective activity, we investigated their influence on expression of calpains and their endogenous inhibitor, calpastatin. We found that ectopic expression of ERalpha in human neuroblastoma SK-N-MC cells led to a ligand-independent constitutive down-regulation of m-calpain accompanied by an up-regulatio…

Calpains promote α2β1 integrin turnover in non-recycling integrin pathway.

2012

Collagen receptor integrins recycle between the plasma membrane and endosomes and facilitate formation and turnover of focal adhesions. In contrast, clustering of α2β1 integrin with antibodies or the human pathogen echovirus 1 (EV1) causes redistribution of α2 integrin to perinuclear multivesicular bodies, α2-MVBs. We show here that the internalized clustered α2 integrin remains in α2-MVBs and is not recycled back to the plasma membrane. Instead, receptor clustering and internalization lead to an accelerated down-regulation of α2β1 integrin compared to the slow turnover of unclustered α2 integrin. EV1 infection or integrin degradation is not associated with proteasomal or autophagosomal pro…