SH3BGRL3 binds to myosin 1c in a calcium dependent manner and modulates migration in the MDA-MB-231 cell line.

BACKGROUND: The human SH3 domain Binding Glutamic acid Rich Like 3 (SH3BGRL3) gene is highly conserved in phylogeny and widely expressed in human tissues. However, its function is largely undetermined. The protein was found to be overexpressed in several tumors, and recent work suggested a possible relationship with EGFR family members. We aimed at further highlighting on these issues and investigated SH3BGRL3 molecular interactions and its role in cellular migration ability. RESULTS: We first engineered the ErbB2-overexpressing SKBR3 cells to express exogenous SH3BGRL3, as well as wild type Myo1c or different deletion mutants. Confocal microscopy analysis indicated that SH3BGRL3 co-localized with Myo1c and ErbB2 at plasma membranes. However, co-immunoprecipitation assays and mass spectrometry demonstrated that SH3BGRL3 did not directly bind ErbB2, but specifically recognized Myo1c, on its IQ-bearing neck region. Importantly, the interaction with Myo1c was Ca2+-dependent. A role for SH3BGRL3 in cell migration was also assessed, as RNA interference of SH3BGRL3 in MDA-MB-231 cells, used as a classical migration model, remarkably impaired the migration ability of these cells. On the other side, its over-expression increased cell motility. CONCLUSION: The results of this study provide insights for the formulation of novel hypotheses on the putative role of SH3BGRL3 protein in the regulation of myosin-cytoskeleton dialog and in cell migration. It could be envisaged the SH3BGRL3-Myo1c interaction as a regulation mechanism for cytoskeleton dynamics. It is well known that, at low Ca2+ concentrations, the IQ domains of Myo1c are bound by calmodulin. Here we found that binding of Myo1c to SH3BGRL3 requires instead the presence of Ca2+. Thus, it could be hypothesized that Myo1c conformation may be modulated by Ca2+-driven mechanisms that involve alternative binding by calmodulin or SH3BGRL3, for the regulation of cytoskeletal activity.

A vector design that allows fast and convenient production of differently tagged proteins.

Recombinant-tagged proteins have a widespread use in experimental research as well as in clinical diagnostic and therapeutic approaches. Well-stocked sets of differently tagged variants of a same protein would be of great help. However, the construction of differently tagging vectors is a demanding task since cloning procedures need several tailored DNA inserts. In this study, we describe a novel vector system that allows a cost- and time-effective production of differently tagged variants of a same protein by using the same DNA fragment and a set of vectors each carrying a different tag. The design of these expression vectors is based on an intronic region that becomes functional upon cloning the insert sequence, splicing of which attaches a certain tag to the protein termini. This strategy allows for the cloning of the fragment that codes for the protein of interest, without any further modification, into different vectors, previously built and ready-to-use, each carrying a tag that will be joined to the protein. Proof of principle for our expression system, presented here, is shown through the production of a functional anti-GD2 Fab fragment tagged with biotin or polyhistidine, or a combination of both, followed by the demonstration of the functional competencies of both the protein and the tags.

Mitochondrial pathway mediates the antileukemic effects of Hemidesmus indicus, a promising botanical drug.

BACKGROUND: Although cancers are characterized by the deregulation of multiple signalling pathways, most current anticancer therapies involve the modulation of a single target. Because of the enormous biological diversity of cancer, strategic combination of agents targeted against the most critical of those alterations is needed. Due to their complex nature, plant products interact with numerous targets and influence several biochemical and molecular cascades. The interest in further development of botanical drugs has been increasing steadily and the FDA recently approved the first new botanical prescription drug. The present study is designed to explore the potential antileukemic properties of Hemidesmus indicus with a view to contributing to further development of botanical drugs. Hemidesmus was submitted to an extensive in vitro preclinical evaluation. METHODOLOGY/PRINCIPAL FINDINGS: A variety of cellular assays and flow cytometry, as well as a phytochemical screening, were performed on different leukemic cell lines. We have demonstrated that Hemidesmus modulated many components of intracellular signaling pathways involved in cell viability and proliferation and altered the protein expression, eventually leading to tumor cell death, mediated by a loss of mitochondrial transmembrane potential and increased Bax/Bcl-2 ratio. ADP, adenine nucleotide translocator and mitochondrial permeability transition pore inhibitors did not reverse Hemidesmus-induced mitochondrial depolarization. Hemidesmus induced a significant [Ca(2+)](i) raise through the mobilization of intracellular Ca(2+) stores. Moreover, Hemidesmus significantly enhanced the antitumor activity of three commonly used chemotherapeutic drugs (methotrexate, 6-thioguanine, cytarabine). A clinically relevant observation is that its cytotoxic activity was also recorded in primary cells from acute myeloid leukemic patients. CONCLUSIONS/SIGNIFICANCE: These results indicate the molecular basis of the antileukemic effects of Hemidesmus and identify the mitochondrial pathways and [Ca(2+)](i) as crucial actors in its anticancer activity. On these bases, we conclude that Hemidesmus can represent a valuable tool in the anticancer pharmacology, and should be considered for further investigations.

Impairment of F1F0-ATPase, adenine nucleotide translocator and adenylate kinase causes mitochondrial energy deficit in human skin fibroblasts with chromosome 21 trisomy.

A central role for mitochondrial dysfunction has been proposed in the pathogenesis of DS (Down's syndrome), a multifactorial disorder caused by trisomy of human chromosome 21. To explore whether and how abnormalities in mitochondrial energy metabolism are involved in DS pathogenesis, we investigated the catalytic properties, gene expression and protein levels of certain proteins involved in mitochondrial ATP synthesis, such as F1F0-ATPase, ANT (adenine nucleotide translocator) and AK (adenylate kinase), in DS-HSF (human skin fibroblasts with trisomic karyotype), comparing them with euploid fibroblasts. In DS-HSF, we found a strong impairment of mitochondrial ATP synthesis due to a reduction in the catalytic efficiency of each of the investigated proteins. This impairment occurred in spite of unchanged gene expression and an increase in ANT and AK protein content, whereas the amount of ATPase subunits was selectively reduced. Interestingly, exposure of DS-HSF to dibutyryl-cAMP, a permanent derivative of cAMP, stimulated ANT, AK and ATPase activities, whereas H89, a specific PKA (protein kinase A) inhibitor, suppressed this cAMPdependent activation, indicating an involvement of the cAMP/PKA-mediated signalling pathway in the ATPase, ANT and AK deficit. Consistently, DS-HSF showed decreased basal levels of cAMP and reduced PKA activity. Despite the impairment of mitochondrial energy apparatus, no changes in cellular energy status, but increased basal levels of L-lactate, were found in DS-HSF, which partially offset for the mitochondrial energy deficit by increasing glycolysis and mitochondrial mass.These results provide new insight into the molecular basis for mitochondrial dysfunction in DS and might provide a molecular explanation for some clinical features of the syndrome.

Pharmacological activities on Ephedra nebrodensis Tineo.

As a part of our endeavour to screen Mediterranean medicinal plants for various pharmacological activities, we evaluated antihistaminic, adaptogenic, anti-inflammatory, antinociceptive, hypotensive and locomotor properties, and antioxidant potential of Ephedra nebrodensis. (1)H-NMR spectroscopy was carried out to identify the plant metabolites, which confirmed the presence of ephedrinic skeleton alkaloids. The ethanol : acetone (1 : 1) extract exhibited dose-related antihistaminic, anti-inflammatory, antinociceptive, hypotensive, antioxidant and locomotor stimulant activity. The plant bears potential for further studies.

Endemic Sardinian plants: the case of Genista cadasonensis Valsecchi.

The flavonoid fraction of the aerial parts of Genista cadasonensis Valsecchi (Leguminosae), an endemic plant from Sardinia, was examined and compared with the flavonoid pattern already known in the Genista genus. This comparison evidenced the endemic nature of this species, showing the presence of a rare flavonoid, the 6-hydroxy-genistein. The antioxidant activity of dichloromethanic, ethanolic and acetonic total extracts of aerial parts was evaluated.

Endemic species of sardo-corso-balearic area: molecular composition and biological assay of Teucrium.

Teucrium marum and T. subspinosum have been extracted with different polarity solvents, each crude extract was analysed with (1)H-NMR to compare the overall metabolic component. The polar extracts showed antioxidant activity in vitro. Verbascoside and arabinosyl-verbascoside were isolated and identified. Their concentrations were in connection to the antioxidant activity.

Crystal structure of the glutaredoxin-like protein SH3BGRL3 at 1.6 Angstrom resolution.

We report the 1.6 Angstrom resolution crystal structure of SH3BGRL3, a member of a new mammalian protein family of unknown function. The observed "thioredoxin fold" of SH3BGRL3 matches the tertiary structure of glutaredoxins, even in the N-terminal region where the sequence similarity between the two protein families is negligible. In particular, SH3BGRL3 displays structural modifications at the N-terminal Cys-x-x-Cys loop, responsible for glutathione binding and catalysis in glutaredoxins. The loop hosts a six residue insertion, yielding an extra N-terminal-capped helical turn, first observed here for the thioredoxin fold. This, together with deletion of both Cys residues, results in a substantial reshaping of the neighboring cleft, where glutathione is hosted in glutaredoxins. While not active in redox reaction and glutathione binding, SH3BGRL3 may act as an endogenous modulator of glutaredoxin activities by competing, with its fully conserved thioredoxin fold, for binding to yet unknown target proteins.

Heart morphogenesis is not affected by overexpression of the Sh3bgr gene mapping to the Down syndrome heart critical region.

Congenital heart disease (CHD) is the most common birth defect in humans and is present in 40% of newborns affected by Down syndrome (DS). The SH3BGR gene maps to the DS-CHD region and is a potential candidate for the pathogenesis of CHD, since it is selectively expressed in cardiac and skeletal muscle. To determine whether overexpression of Sh3bgr in the murine heart may cause abnormal cardiac development, we have generated transgenic mice using a cardiac- and skeletal-muscle-specific promoter to drive the expression of a Sh3bgr transgene. We report here that heart morphogenesis is not affected by overexpression of Sh3bgr.

Characterisation and expression analysis of the WDR9 gene, located in the Down critical region-2 of the human chromosome 21.

We report the isolation and characterisation of the gene WDR9 (WD Repeat 9), located in the Down Syndrome critical region-2 (DCR-2) from the human chromosome 21. This gene spans 125 kb of genomic sequence and is organised in 41 exons and 40 introns. The WDR9 cDNA has a size of 13 kb and encodes for a putative protein of 2269 amino acids with a potential location in the nucleus. Expression analysis in different human adult tissues and in cultured cell lines indicates that the gene has several tissue-specific transcripts. The more significant protein signatures in the WDR9 protein sequence are for WD repeats, bromodomain, beta-ketoacyl synthases, and ribonucleoprotein (RNP). The WDR9 protein has a high similarity with the Mus musculus neuronal differentiation protein (NDRP) and a region of similarity with the region of the Yotiao protein that has been proposed to bind the NR1 subunit of the NMDA receptor. The presence of protein-protein interaction domains as such the WD repeats, and the similarity of the WDR9 protein to regulatory proteins suggest a potential involvement in some of the clinical features associated to the DCR-2.

The identification of a novel human homologue of the SH3 binding glutamic acid-rich (SH3BGR) gene establishes a new family of highly conserved small proteins related to Thioredoxin Superfamily.

The SH3 binding glutamic acid-rich (SH3BGR) gene was cloned in an effort to identify genes located to human chromosome 21, within the congenital heart disease region, and expressed in the developing heart. After the identification of SH3BGR, two human homologous genes, SH3BGRL and SH3BGRL3, were identified and mapped to chromosome Xq13.3 and 1p34.3-35, respectively. SH3BGRL and SH3BGRL3 code for small proteins similar to the N-terminal region of the SH3BGR protein. SH3BGRL3 protein shows a significant similarity to Glutaredoxin 1 of Escherichia coli, and all the three proteins are predicted to belong to Thioredoxin-like protein Superfamily. Here we describe the identification and characterization of an additional human homologue of SH3BGR, named SH3BGRL2. The SH3BGRL2 gene maps to chromosome 6q13-15 and its messenger RNA has a large 3' untranslated region containing several AUUUA repeats. SH3BGRL2 codes for a protein of 107 amino acids, which, like SH3BGRL and SH3BGRL3 proteins, is highly homologous to the N-terminal region of the SH3BGR protein and appears to be related to Glutaredoxins and to PKC-interacting cousin of thioredoxin homology domain. We propose that the identification of SH3BGRL2 establishes a novel family of human genes, coding for highly conserved small proteins belonging to Thioredoxin-like protein Superfamily.

AgeWa: an integrated approach for antisense experiment design.

One of the major fallouts of the human genome project relates to the investigation of the molecular mechanisms of diseases. Identification of genes which are involved in a specific pathological process and characterization of their interactions is of fundamental importance for supporting the drug design processes. Discovery of targets and the related experimental validation is a critical step in the development of new drugs. The new experimental methods for gene expression analysis, such as microarray technology, allows for the concurrent evaluation of the expression of multiple genes. The outcome of these new experimental methods requires a subsequent validation of the gene function by using in vitro or in vivo models. In the last decade, one of the most promising methodologies for the investigation of gene function relies upon antisense oligonucleotides (ASO). The crucial step in antisense experiment design is the characterization of the nucleotide domains that can efficiently be targeted by this kind of synthetic molecule. At present, no standardized procedures for target selection are available. In this paper, we propose an integrative approach to ASO target selection: the proposed tool Automatic Gene Walk (AgeWa) combines a neural filter with database mining for the prediction of the optimal target for antisense action.