Human cytochrome C natural variants: Studying the membrane binding properties of G41S and Y48H by fluorescence energy transfer and molecular dynamics.

Cytochrome C (cyt C), the protein involved in oxidative phosphorylation, plays several other crucial roles necessary for both cell life and death. Studying natural variants of cyt C offers the possibility to better characterize the structure-to-function relationship that modulates the different activities of this protein. Naturally mutations in human cyt C (G41S and Y48H) occur in the protein central Ω-loop and cause thrombocytopenia 4.

In Vivo Identification of H3K9me2/H3K79me3 as an Epigenetic Barrier to Carcinogenesis.

The highly dynamic nature of chromatin's structure, due to the epigenetic alterations of histones and DNA, controls cellular plasticity and allows the rewiring of the epigenetic landscape required for either cell differentiation or cell (re)programming. To dissect the epigenetic switch enabling the programming of a cancer cell, we carried out wide genome analysis of Histone 3 (H3) modifications during osteogenic differentiation of SH-SY5Y neuroblastoma cells. The most significant modifications concerned H3K27me2/3, H3K9me2, H3K79me1/2, and H3K4me1 that specify the process of healthy adult stem cell differentiation.

Intentional Understanding Through Action Coordination in Early Triadic Interactions.

The ability to understand the behaviour of other people in intentional terms has been traditionally explained by resorting to inferential mechanisms that would allow individuals to access the internal mental states of others. In recent years, the second-person perspective has established itself as a theoretical alternative to traditional models. It argues that intentional understanding is an embodied, natural, and immediate process that occurs in situations such as face-to-face early dyadic interactions between adults and infants.

The Puzzling Problem of Cardiolipin Membrane-Cytochrome c Interactions: A Combined Infrared and Fluorescence Study.

The interaction of cytochrome c (cyt c) with natural and synthetic membranes is known to be a complex phenomenon, involving both protein and lipid conformational changes. In this paper, we combined infrared and fluorescence spectroscopy to study the structural transformation occurring to the lipid network of cardiolipin-containing large unilamellar vesicles (LUVs). The data, collected at increasing protein/lipid ratio, demonstrate the existence of a multi-phase process, which is characterized by: (i) the interaction of cyt c with the lipid polar heads; (ii) the lipid anchorage of the protein on the membrane surface; and (iii) a long-distance order/disorder transition of the cardiolipin acyl chains.

Transglutaminase 3 Reduces the Severity of Psoriasis in Imiquimod-Treated Mouse Skin.

Four transglutaminase (TG) isoforms have been detected in epidermal keratinocytes: TG1, TG2, TG3, and TG5. Except for TG1 and TG3, their contribution to keratinocyte development and structure remains undefined. In this paper, we focused on the roles of TG2 and TG3 in imiquimod-induced psoriasis in mouse skin.

Kruppel-like factor 4 regulates keratinocyte senescence.

Keratinocyte replicative senescence has an important role in time-related changes of epidermis. Previous studies demonstrated that miRNAs play key roles in inhibiting proliferation and in the acquisition of the keratinocyte senescent phenotype as well as in individual ageing. Kruppel-like factor 4 is a transcription factor with dual functions in keratinocytes, being a stemness factor and a pro-differentiation factor.

Omega-3 and Omega-6 Fatty Acids Act as Inhibitors of the Matrix Metalloproteinase-2 and Matrix Metalloproteinase-9 Activity.

Polyunsaturated fatty acids have been reported to play a protective role in a wide range of diseases characterized by an increased metalloproteinases (MMPs) activity. The recent finding that omega-3 and omega-6 fatty acids exert an anti-inflammatory effect in periodontal diseases has stimulated the present study, designed to determine whether such properties derive from a direct inhibitory action of these compounds on the activity of MMPs. To this issue, we investigated the effect exerted by omega-3 and omega-6 fatty acids on the activity of MMP-2 and MMP-9, two enzymes that actively participate to the destruction of the organic matrix of dentin following demineralization operated by bacteria acids.

Metabolic pathways regulated by p63.

The transcription factor p63 belongs to the p53-family and is a master regulator of proliferative potential, lineage specification, and differentiation in epithelia during development and tissue homeostasis. In cancer, p63 contribution is isoform-specific, with both oncogenic and tumour suppressive roles attributed, for ΔNp63 and TAp63, respectively. Recently, p53 and TAp73, in line with other tumour suppressor genes, have emerged as important regulators of energy metabolism and metabolic reprogramming in cancer.

The key role played by charge in the interaction of cytochrome c with cardiolipin.

Cytochrome c undergoes structural variations upon binding of cardiolipin, one of the phospholipids constituting the mitochondrial membrane. Although several mechanisms governing cytochrome c/cardiolipin (cyt c/CL) recognition have been proposed, the interpretation of the process remains, at least in part, unknown. To better define the steps characterizing the cyt c-CL interaction, the role of Lys72 and Lys73, two residues thought to be important in the protein/lipid binding interaction, were recently investigated by mutagenesis.

Setdb1, a novel interactor of ΔNp63, is involved in breast tumorigenesis.

ΔNp63 has been recently involved in self-renewal potential of breast cancer stem cells. Although the p63 transcriptional profile has been extensively characterized, our knowledge of the p63-binding partners potentially involved in the regulation of breast tumour progression is limited. Here, we performed the yeast two hybrid approach to identify p63α interactors involved in breast tumorigenesis and we found that SETDB1, a histone lysine methyl transferases, interacts with ΔNp63α and that this interaction contributes to p63 protein stability.

Role of lysines in cytochrome c-cardiolipin interaction.

Cytochrome c undergoes structural variations during the apoptotic process; such changes have been related to modifications occurring in the protein when it forms a complex with cardiolipin, one of the phospholipids constituting the mitochondrial membrane. Although several studies have been performed to identify the site(s) of the protein involved in the cytochrome c-cardiolipin interaction, to date the location of this hosting region(s) remains unidentified and is a matter of debate. To gain deeper insight into the reaction mechanism, we investigate the role that the Lys72, Lys73, and Lys79 residues play in the cytochrome c-cardiolipin interaction, as these side chains appear to be critical for cytochrome c-cardiolipin recognition.

Conversion of cytochrome c into a peroxidase: inhibitory mechanisms and implication for neurodegenerative diseases.

A further function of cytochrome c (cyt c), beyond respiration, is realized outside mitochondria in the apoptotic program. In the early events of apoptosis, the interaction of cyt c with a mitochondrion-specific phospholipid, cardiolipin (CL), brings about a conformational transition of the protein and acquirement of peroxidase activity. The hallmark of cyt c with peroxidase activity is its partial unfolding accompanied by loosening of the Fe sixth axial bond and an enhanced access of the heme catalytic site to small molecules like H2O2.

The effects of ATP and sodium chloride on the cytochrome c-cardiolipin interaction: the contrasting behavior of the horse heart and yeast proteins.

In cells a portion of cytochrome c (cyt c) (15-20%) is tightly bound to cardiolipin (CL), one of the phospholipids constituting the mitochondrial membrane. The CL-bound protein, which has nonnative tertiary structure, altered heme pocket, and disrupted Fe(III)-M80 axial bond, is thought to play a role in the apoptotic process. This has attracted considerable interest in order to clarify the mechanisms governing the cyt c-CL interaction.

Salivary miRNAome profiling uncovers epithelial and proliferative miRNAs with differential expression across dentition stages.

Saliva's ability to mirror the internal physiological environment of an organism coupled with its facile accessibility makes it an attractive diagnostic medium. The finding of microRNAs (miRNAs) in saliva has expanded the field of biomarker discovery since these tiny non-coding RNAs affect various physiological processes and diseases. Few reports have linked miRNAs to tooth development and eruption, with none having studied this in humans.

Differential control of TAp73 and DeltaNp73 protein stability by the ring finger ubiquitin ligase PIR2.

p73 is a p53-related transcription factor with fundamental roles in development and tumor suppression. Transcription from two different promoters on the p73 gene results in generation of transcriptionally active TAp73 isoforms and dominant negative DeltaNp73 isoforms with opposing pro- and anti-apoptotic functions. Therefore, the relative ratio of each isoform is an important determinant of the cell fate.

Extended cardiolipin anchorage to cytochrome c: a model for protein-mitochondrial membrane binding.

Two models have been proposed to explain the interaction of cytochrome c with cardiolipin (CL) vesicles. In one case, an acyl chain of the phospholipid accommodates into a hydrophobic channel of the protein located close the Asn52 residue, whereas the alternative model considers the insertion of the acyl chain in the region of the Met80-containing loop. In an attempt to clarify which proposal offers a more appropriate explanation of cytochrome c-CL binding, we have undertaken a spectroscopic and kinetic study of the wild type and the Asn52Ile mutant of iso-1-cytochrome c from yeast to investigate the interaction of cytochrome c with CL vesicles, considered here a model for the CL-containing mitochondrial membrane.

ATP acts as a regulatory effector in modulating structural transitions of cytochrome c: implications for apoptotic activity.

The binding of lipids (free fatty acids as well as acidic phospholipids) to cytochrome c (cyt c) induces conformational changes and partial unfolding of the protein, strongly influencing cyt c oxidase/peroxidase activity. ATP is unique among the nucleotides in being able to turn non-native states of cyt c back to the native conformation. The peroxidase activity acquired by lipid-bound cyt c turns out to be very critical in the early stages of apoptosis.

Probing the effect of mutations on cytochrome C stability.

Although the tertiary structures of mitochondrial cytochromes c (cyts c) seem to be remarkably similar, there are variations in their amino acid sequences, stability and functional properties. GdnHCl-induced unfolding experiments on engineered yeast and horse cyt c were carried out with the aim to to clarify, at molecular level, some aspects concerning the stability of this class of proteins. The results obtained are discussed in the light of the three-dimensional structures of the two proteins.

Nanoscopic and redox characterization of engineered horse cytochrome C chemisorbed on a bare gold electrode.

In this paper, we exploit the potential offered by site-directed mutagenesis to achieve direct adsorption of horse cyt c on a bare gold electrode surface. To this issue, the side chain T102 has been replaced by a cysteine. T102 is close to the surface exposed C-terminal residue (E104), therefore the T102C mutation is expected to generate an exposed cysteine side chain able to facilitate protein binding to the electrode via the sulphur atom (analogously to what observed for yeast iso-1-cyt c).