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Quorum Sensing and Essential Oils
Published in K. Hüsnü Can Başer, Gerhard Buchbauer, Handbook of Essential Oils, 2020
Isabel Charlotte Soede, Gerhard Buchbauer
Gram-positive bacteria use autoinducing peptides (AIPs) as signals. AIPs cannot freely diffuse through the membrane; they bind on extracellular histidine kinase receptors. This signaling way is classified as a “two-component” type, as it consists of a sensor and a response-regulator protein. As soon as the molecule binds, the kinase activity of the receptor is activated, which leads to a phosphorylation cascade resulting in the binding of a responsive regulator, a DNA-binding regulator controlling the transcription of QS genes. Bacteria using this kind of signaling path are Bacillus subtilis, Streptococcus pneumonaiae, and Staphylococcus aureus. For the excretion of AIPs, bacteria often express ATP-binding cassette (ABC)-transporter (Kleerebezem et al., 1997).
Glycogenosis type I – von Gierke disease
Published in William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop, Atlas of Inherited Metabolic Diseases, 2020
William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop
The active site of the enzyme is within the lumen of the endoplasmic reticulum [70]. Normal activity of the enzyme requires the activity of six different proteins or subunits in the enzyme complex [71, 72]. The discovery of these components and the elucidation of the function of the complex were the results of the study of patients with glycogen storage disease. The classic enzyme, or the catalytic subunit whose deficiency causes type Ia, is a 36.5-kDa protein [72] that catalyzes the hydrolysis of a number of phosphate compounds, including carbamylphosphate and pyrophosphate, as well as glucose-6-phosphate [73, 74]. A microsomal regulatory protein has been isolated as a 21-kDa stabilizing protein because it stabilizes the activity of the catalytic protein during purification [75]. It binds calcium and is essential for normal activity. Its deficiency leads to glycogenosis type Iasp [7].
Cell structure, function and adaptation
Published in C. Simon Herrington, Muir's Textbook of Pathology, 2020
Perhaps as many as 10,000 genes are actively expressed in a cell to maintain cell viability and function. These genes code for a variety of protein products involved directly and indirectly in energy production, protection against the side effects of carbohydrate combustion in the presence of oxygen, maintenance of cell structure, and waste disposal. These gene products interact with each other so that cell homeostasis is a complex interactive network (Figure 2.3). The regulation of gene expression is therefore complex, with many genes being expressed only when needed through the assembly of regulatory protein complexes which include transcription factors. This gives the cell the ability to express certain genes selectively at appropriate levels in response to stimuli. In addition to controlling gene (and hence protein) expression, the cell controls protein function through a network of competing enzymes that regulate the activity, structure, and function of other proteins. Thus, phosphorylases and kinases act at suitable amino acid residues to dephosphorylate or phosphorylate their targets, respectively. These cause pH-dependent conformational shifts that alter both structure and function. Enzymes can, therefore, modify proteins after they have been translated (post-translational modification) to alter protein function, providing a rapid response to the changing intracellular environment.
Short-term exposure to an obesogenic diet causes dynamic dysregulation of proteasome-mediated protein degradation in the hypothalamus of female rats
Published in Nutritional Neuroscience, 2023
Taylor McFadden, Kayla Farrell, Kiley Martin, Madeline Musaus, Timothy J. Jarome
The ubiquitin-proteasome system (UPS) is a highly conserved, tightly controlled intracellular mechanism that mediates protein degradation in cells [10–12]. In this system, proteins are tagged via the covalent attachment of the small regulatory protein known as ubiquitin, which marks substrates for degradation by the large multi-subunit proteasome complex. Target proteins can acquire a monoubiquitin modification, which is independent of protein degradation, or one of eight polyubiquitin modifications in which a new ubiquitin binds to a previous ubiquitin, usually at a lysine site. Of these diverse polyubiquitin modifications, which have different functions in the cell, lysine 48 (K48) is the conical protein degradation mark and is the most abundant form of ubiquitination in cells [13,14]. Recently, numerous studies have highlighted the role of the UPS, particularly the protein degradation process, in regulating various intracellular processes and synaptic plasticity [15–18] and dysregulation of ubiquitin-proteasome signaling is thought to be critically involved in the development of various diseases [19].
Long Non-Coding RNA and Chemoresistance in Bladder Cancer – A Mini Review
Published in Cancer Investigation, 2023
Ana Paula Braga Lima, Glenda Nicioli da Silva
One of the defining features of lncRNAs is the acquisition of a secondary and tertiary 3D structure, which is mostly dependent on Watson–Crick base pairing, enabling them to exert both RNA-related and protein-like functions, based on nucleic acid complementarity and their spatial conformation, respectively (19). Individual lncRNAs can exert functions in both the nucleus and cytoplasm, be transmitted to neighboring cells through exosome trafficking and be processed to produce smaller RNAs with distinct functions (19). Moreover, lncRNAs could regulate transcription, recruiting a regulatory protein complex to a gene, inhibiting the interaction of a transcriptional regulatory molecule, modulating the transcription of nearby mRNA genes, or regulating genome organization and the architecture of the nucleus (20).
In Silico and in Vivo Analysis of HIV-1 Rev Regulatory Protein for Evaluation of a Multiepitope-based Vaccine Candidate
Published in Immunological Investigations, 2022
Samaneh H. Shabani, Kimia Kardani, Alireza Milani, Azam Bolhassani
Other major point is the importance of Rev regulatory protein as an antigen candidate in vaccine design. As known, HIV-1 Rev protein helps the transportation of viral RNA without processing from nucleus to cytoplasm for the translation process (Arya et al. 2015; Nabel et al. 2011). Recent studies showed that the CD8+ cytotoxic T cell (CTL) activity against Tat and Rev proteins could control HIV-1 load (Verrier et al. 2002). Moreover, the immunogenicity of DNA vectors harboring HIV-1 nef, tat and rev genes individually showed that the pBN-nef construct induced humoral and cellular immunity using intramuscular and intradermal delivery. In contrast, the pBN-rev construct only induced the CTL responses and the pBN-tat construct did not elicit any effective immune responses (Tähtinen et al. 2001). The DNA vectors encoding the HIV-1 Env and Rev proteins stimulated significantly antigen-specific antibodies and suppressed HIV-1 infection in mouse, rabbit, or macaque, as well (Okuda et al. 1995).