isoforms
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- MeSH
- kardiomyocyty enzymologie fyziologie MeSH
- protein - isoformy klasifikace MeSH
- sodíko-draslíková ATPasa fyziologie MeSH
- Publikační typ
- přehledy MeSH
Metallothioneins (MTs) belong to a group of small cysteine-rich proteins that are ubiquitous throughout all kingdoms. The main function of MTs is scavenging of free radicals and detoxification and homeostating of heavy metals. In humans, 16 genes localized on chromosome 16 have been identified to encode four MT isoforms labelled by numbers (MT-1-MT-4). MT-2, MT-3 and MT-4 proteins are encoded by a single gene. MT-1 comprises many (sub)isoforms. The known active MT-1 genes are MT-1A, -1B, -1E, -1F, -1G, -1H, -1M and -1X. The rest of the MT-1 genes (MT-1C, -1D, -1I, -1J and -1L) are pseudogenes. The expression and localization of individual MT (sub)isoforms and pseudogenes vary at intra-cellular level and in individual tissues. Changes in MT expression are associated with the process of carcinogenesis of various types of human malignancies, or with a more aggressive phenotype and therapeutic resistance. Hence, MT (sub)isoform profiling status could be utilized for diagnostics and therapy of tumour diseases. This review aims on a comprehensive summary of methods for analysis of MTs at (sub)isoforms levels, their expression in single tumour diseases and strategies how this knowledge can be utilized in anticancer therapy.
- MeSH
- epigeneze genetická MeSH
- lidé MeSH
- metalothionein metabolismus MeSH
- nádory farmakoterapie genetika metabolismus MeSH
- protein - isoformy MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Yes-associated protein 1 (YAP1) is a transcriptional co-activator downstream of Hippo pathway. The pathway exerts crucial roles in organogenesis and its dysregulation is associated with the spreading of different cancer types. YAP1 gene encodes for multiple protein isoforms, whose specific functions are not well defined. We demonstrate the splicing of isoform-specific mRNAs is controlled in a stage- and tissue-specific fashion. We designed expression vectors encoding for the most-represented isoforms of YAP1 with either one or two WW domains and studied their specific signaling activities in YAP1 knock-out cell lines. YAP1 isoforms display both common and unique functions and activate distinct transcriptional programs, as the result of their unique protein interactomes. By generating TEAD-based transcriptional reporter cell lines, we demonstrate individual YAP1 isoforms display unique effects on cell proliferation and differentiation. Finally, we illustrate the complexity of the regulation of Hippo-YAP1 effector in physiological and in pathological conditions of the heart.
The objective of this study was to determine whether human auricular chondrocytes can also express ?--smooth muscle actin. Immunohistochemistry using monoclonal antibodies for ?-smooth actin, muscle-specific actin, ß-actin, S-100 protein, CD34, and desmin was performed on samples of human ear cartilage obtained from 20 individuals during a partial resection of the ear for different reasons. Moreover, the RT-PCR analysis of actin isoforms in auricular chondrocytes was performed. Approximately 60 % of the chondrocytes of the ear cartilage expressed ?-smooth muscle actin as demonstrated by immunohistochemistry in all the examined samples. Actin-positive chondrocytes occurred in both external subperichondrial layers of the auricular cartilage. This finding was confirmed by the RT-PCR technique. The knowledge of this fact could help us to better understand the chondrocyte changes occurring during the healing and transplantation of auricular cartilage. The question of whether it is necessary to refer to these predominating cells in ear cartilage as myochondrocytes is considered. This is the first report of an unusual immunophenotype and contractile potential for human auricular chondrocytes.
- MeSH
- aktiny genetika klasifikace MeSH
- antigeny CD34 genetika MeSH
- barvení a značení metody využití MeSH
- chondrocyty cytologie MeSH
- financování vládou MeSH
- lidé MeSH
- polymerázová řetězová reakce s reverzní transkripcí metody využití MeSH
- protein - isoformy genetika MeSH
- ušní chrupavka cytologie růst a vývoj MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- srovnávací studie MeSH
Cellular senescence is a hallmark of normal aging and aging-related syndromes, including the premature aging disorder Hutchinson-Gilford Progeria Syndrome (HGPS), a rare genetic disorder caused by a single mutation in the LMNA gene that results in the constitutive expression of a truncated splicing mutant of lamin A known as progerin. Progerin accumulation leads to increased cellular stresses including unrepaired DNA damage, activation of the p53 signaling pathway and accelerated senescence. We previously established that the p53 isoforms ∆133p53 and p53β regulate senescence in normal human cells. However, their role in premature aging is unknown. Here we report that p53 isoforms are expressed in primary fibroblasts derived from HGPS patients, are associated with their accelerated senescence and that their manipulation can restore the replication capacity of HGPS fibroblasts. We found that in near-senescent HGPS fibroblasts, which exhibit low levels of ∆133p53 and high levels of p53β, restoration of Δ133p53 expression was sufficient to extend replicative lifespan and delay senescence, despite progerin levels and abnormal nuclear morphology remaining unchanged. Conversely, Δ133p53 depletion or p53β overexpression accelerated the onset of senescence in otherwise proliferative HGPS fibroblasts. Our data indicate that Δ133p53 exerts its role by modulating full-length p53 (FLp53) signaling to extend the replicative lifespan and promotes the repair of spontaneous progerin-induced DNA double-strand breaks (DSBs). We showed that Δ133p53 dominant-negative inhibition of FLp53 occurs directly at the p21/CDKN1A and miR-34a promoters, two p53 senescence-associated genes. In addition, Δ133p53 expression increased the expression of DNA repair RAD51, likely through upregulation of E2F1, a transcription factor that activates RAD51, to promote repair of DSBs. In summary, our data indicate that Δ133p53 modulates p53 signaling to repress progerin-induced early onset of senescence in HGPS cells. Therefore, restoration of ∆133p53 expression may be a novel therapeutic strategy to treat aging-associated phenotypes of HGPS in vivo.
- MeSH
- časové faktory MeSH
- fibroblasty patologie fyziologie MeSH
- kultivované buňky MeSH
- lidé MeSH
- nádorový supresorový protein p53 genetika fyziologie MeSH
- poškození DNA genetika MeSH
- předčasné stárnutí genetika patologie MeSH
- progerie genetika patologie MeSH
- protein - isoformy fyziologie MeSH
- stárnutí buněk genetika MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
The p53 protein is a key tumor suppressor and the most commonly mutated and down-regulated protein in human tumors. It functions mainly through interaction with DNA, and p53 acts as a transcription factor that recognizes the so-called p53 target sites on the promoters of various genes. P53 has been shown to exist as many isoforms, including three C-terminal isoforms that are produced by alternative splicing. Because the C-terminal domain is responsible for sequence-nonspecific binding and regulation of p53 binding, we have analyzed DNA recognition by these C-terminal isoforms. Using atomic force microscopy, we show for the first time that all C-terminal isoforms recognize superhelical DNA. It is particularly noteworthy that a sequence-specific p53 consensus binding site is bound by p53α and β isoforms with similar affinities, whilst p53α shows higher binding to a quadruplex sequence than both p53β and p53γ, and p53γ loses preferential binding to both the consensus binding sequence and the quadruplex-forming sequence. These results show the important role of the variable p53 C-terminal amino acid sequences for DNA recognition.
Apolipoprotein E (APOE) is distributed across various human tissues and plays a crucial role in lipid metabolism. Recent investigations have uncovered an additional facet of APOE's functionality, revealing its role in host defense against bacterial infections. To assess the antibacterial attributes of APOE3 and APOE4, we conducted antibacterial assays using Pseudomonas aeruginosa and Escherichia coli. Exploring the interaction between APOE isoforms and lipopolysaccharides (LPSs) from E. coli, we conducted several experiments, including gel shift assays, CD, and fluorescence spectroscopy. Furthermore, the interaction between APOE isoforms and LPS was further substantiated through atomic resolution molecular dynamics simulations. The presence of LPS induced the aggregation of APOE isoforms, a phenomenon confirmed through specific amyloid staining, as well as fluorescence and electron microscopy. The scavenging effects of APOE3/4 isoforms were studied through both in vitro and in vivo experiments. In summary, our study established that APOE isoforms exhibit binding to LPS, with a more pronounced affinity and complex formation observed for APOE4 compared with APOE3. Furthermore, our data suggest that APOE isoforms neutralize LPS through aggregation, leading to a reduction of local inflammation in experimental animal models. In addition, both isoforms demonstrated inhibitory effects on the growth of P. aeruginosa and E. coli. These findings provide new insights into the multifunctionality of APOE in the human body, particularly its role in innate immunity during bacterial infections.
- MeSH
- apolipoprotein E3 * metabolismus chemie farmakologie MeSH
- apolipoprotein E4 * metabolismus chemie farmakologie MeSH
- Escherichia coli metabolismus MeSH
- lidé MeSH
- lipopolysacharidy * metabolismus chemie MeSH
- myši MeSH
- protein - isoformy chemie metabolismus MeSH
- Pseudomonas aeruginosa metabolismus MeSH
- simulace molekulární dynamiky MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The finite proliferative potential of normal human cells leads to replicative cellular senescence, which is a critical barrier to tumour progression in vivo. We show that the human p53 isoforms Delta133p53 and p53beta function in an endogenous regulatory mechanism for p53-mediated replicative senescence. Induced p53beta and diminished Delta133p53 were associated with replicative senescence, but not oncogene-induced senescence, in normal human fibroblasts. The replicatively senescent fibroblasts also expressed increased levels of miR-34a, a p53-induced microRNA, the antisense inhibition of which delayed the onset of replicative senescence. The siRNA (short interfering RNA)-mediated knockdown of endogenous Delta133p53 induced cellular senescence, which was attributed to the regulation of p21(WAF1) and other p53 transcriptional target genes. In overexpression experiments, whereas p53beta cooperated with full-length p53 to accelerate cellular senescence, Delta133p53 repressed miR-34a expression and extended the cellular replicative lifespan, providing a functional connection of this microRNA to the p53 isoform-mediated regulation of senescence. The senescence-associated signature of p53 isoform expression (that is, elevated p53beta and reduced Delta133p53) was observed in vivo in colon adenomas with senescent phenotypes. The increased Delta133p53 and decreased p53beta isoform expression found in colon carcinoma may signal an escape from the senescence barrier during the progression from adenoma to carcinoma.
- MeSH
- genový knockdown MeSH
- lidé MeSH
- mikro RNA metabolismus MeSH
- mutace genetika MeSH
- nádorové buněčné linie MeSH
- nádorový supresorový protein p53 * genetika metabolismus MeSH
- nádory tračníku genetika metabolismus MeSH
- protein - isoformy genetika metabolismus MeSH
- regulace genové exprese u nádorů MeSH
- stárnutí buněk * MeSH
- Check Tag
- lidé MeSH
The p53 family of proteins evolved from a common ancestor into three separate genes encoding proteins that act as transcription factors with distinct cellular roles. Isoforms of each member that lack specific regions or domains are suggested to result from alternative transcription start sites, alternative splicing or alternative translation initiation, and have the potential to exponentially increase the functional repertoire of each gene. However, evidence supporting the presence of individual protein variants at functional levels is often limited and is inferred by mRNA detection using highly sensitive amplification techniques. We provide a critical appraisal of the current evidence for the origins, expression, functions and regulation of p53-family isoforms. We conclude that despite the wealth of publications, several putative isoforms remain poorly established. Future research with improved technical approaches and the generation of isoform-specific protein detection reagents is required to establish the physiological relevance of p53-family isoforms in health and disease. In addition, our analyses suggest that p53-family variants evolved partly through convergent rather than divergent evolution from the ancestral gene.
- MeSH
- alternativní sestřih * MeSH
- lidé MeSH
- messenger RNA metabolismus genetika MeSH
- molekulární evoluce MeSH
- nádorový supresorový protein p53 * metabolismus genetika MeSH
- počátek transkripce MeSH
- protein - isoformy * genetika metabolismus MeSH
- regulace genové exprese MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
TP73 is a member of the TP53 gene family and produces N- and C-terminal protein isoforms through alternative promoters, alternative translation initiation and alternative splicing. Most notably, p73 protein isoforms may either contain a p53-like transactivation domain (TAp73 isoforms) or lack this domain (ΔTAp73 isoforms) and these variants have opposing or independent functions. To date, there is a lack of well-characterised isoform-specific p73 antibodies. Here, we produced polyclonal and monoclonal antibodies to N-terminal p73 variants and the C-terminal p73α isoform, the most common variant in human tissues. These reagents show that TAp73 is a marker of multiciliated epithelial cells, while ΔTAp73 is a marker of non-proliferative basal/reserve cells in squamous epithelium. We were unable to detect ΔNp73 variant proteins, in keeping with recent data that this is a minor form in human tissues. Most cervical squamous cell carcinomas (79%) express p73α, and the distribution of staining in basal cells correlated with lower tumour grade. TAp73 was found in 17% of these tumours, with a random distribution and no association with clinicopathological features. These data indicate roles for ΔTAp73 in maintaining a non-proliferative state of undifferentiated squamous epithelial cells and for TAp73 in the production of differentiated multiciliated cells.
- MeSH
- epitelové buňky metabolismus MeSH
- lidé MeSH
- monoklonální protilátky MeSH
- nádorové buněčné linie MeSH
- nádory děložního čípku metabolismus patologie genetika MeSH
- nádory metabolismus patologie genetika MeSH
- protein - isoformy * metabolismus genetika MeSH
- protein p73 * metabolismus genetika MeSH
- spinocelulární karcinom metabolismus patologie genetika MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
