Publications by authors named "Michael J Ragusa"

Article Synopsis
  • Pseudomonas aeruginosa causes respiratory infections in cystic fibrosis patients and produces a virulence factor called Cif, which worsens patient outcomes by decreasing CFTR levels and disrupting healing signals.!* -
  • The virulence factor Cif is regulated by a protein called CifR, which is the first known bacterial transcriptional regulator that senses epoxides, although how it functions at a molecular level has not been fully explored.!* -
  • Through biochemical and structural studies, researchers revealed how CifR binds to DNA and identified key changes in its structure that facilitate gene regulation, highlighting the critical role of the Cys107 residue in sensing epoxides and releasing DNA.!*
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Many bacteria have hemerythrin (Hr) proteins that bind O, including , in which microoxia-induced Hr (Mhr) provide fitness advantages under microoxic conditions. Mhr has a 23 amino-acid extension at its -terminus relative to a well-characterized Hr from , and similar extensions are also found in Hrs from other bacteria. The last 11 amino acids of this extended, -terminal tail are highly conserved in gammaproteobacteria and predicted to form a helix with positively charged and hydrophobic faces.

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During autophagy, potentially toxic cargo is enveloped by a newly formed autophagosome and trafficked to the lysosome for degradation. Ubiquitinated protein aggregates, a key target for autophagy, are identified by multiple autophagy receptors. NBR1 is an archetypal autophagy receptor and an excellent model for deciphering the role of the multivalent, heterotypic interactions made by cargo-bound receptors.

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Cytochrome c (c) is a diheme protein implicated as an electron donor to cbb oxidases in multiple pathogenic bacteria. Despite its prevalence, understanding of how specific structural features of c optimize its function is lacking. The human pathogen Neisseria gonorrhoeae (Ng) thrives in low oxygen environments owing to the activity of its cbb oxidase.

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The opportunistic pathogen infects cystic fibrosis (CF) patient airways and produces a virulence factor Cif that is associated with worse outcomes. Cif is an epoxide hydrolase that reduces cell-surface abundance of the cystic fibrosis transmembrane conductance regulator (CFTR) and sabotages pro-resolving signals. Its expression is regulated by a divergently transcribed TetR family transcriptional repressor.

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Autophagy is essential for the degradation of mitochondria from yeast to humans. Mitochondrial autophagy in yeast is initiated when the selective autophagy scaffolding protein Atg11 is recruited to mitochondria through its interaction with the selective autophagy receptor Atg32. This also results in the recruitment of small 30 nm vesicles that fuse to generate the initial autophagosomal membrane.

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Background: Source plasma collections are needed to satisfy the growing demand for plasma-derived medicinal products. The US plasma collection target volume has been guided by a standard weight-based FDA-issued nomogram (STAN) since 1992. In this research, large-scale US-based real-world data (RWD) were analyzed to confirm the safety and volume gains of a newly introduced personalized nomogram (PERS) that was previously studied in a premarket randomized controlled environment.

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Small 30-nm vesicles containing the integral membrane protein Atg9 provide the initial membrane source for autophagy in yeast. Atg23 is an Atg9 binding protein that is required for Atg9 vesicle trafficking but whose exact function is unknown. In our recent paper, we explored the function of Atg23 using an approach combining cellular biology and biochemistry on purified protein.

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Cells rely on autophagy to degrade cytosolic material and maintain homeostasis. During autophagy, content to be degraded is encapsulated in double membrane vesicles, termed autophagosomes, which fuse with the yeast vacuole for degradation. This conserved cellular process requires the dynamic rearrangement of membranes.

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Background And Objectives: There is less robust data describing adverse events (AEs) in source plasma donors than in whole blood donors, particularly regarding time to AEs (TAEs). We, therefore, sought to characterize TAE and the influence of donor characteristics in a large-scale clinical trial dataset.

Materials And Methods: TAE was calculated utilizing data from the IMPACT (IMproving PlasmA CollecTion) trial, with linear regression analyses performed to determine the influence of donor parameters on TAE.

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Eukaryotes maintain cellular health through the engulfment and subsequent degradation of intracellular cargo using macroautophagy. The function of Atg23, despite being critical to the efficiency of this process, is unclear due to a lack of biochemical investigations and an absence of any structural information. In this study, we use a combination of in vitro and in vivo methods to show that Atg23 exists primarily as a homodimer, a conformation facilitated by a putative amphipathic helix.

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The sorting nexin (SNX) proteins, Atg20 and Atg24, are involved in nonselective autophagy, are necessary for efficient selective autophagy, and are required for the cytoplasm-to-vacuole transport pathway. However, the specific roles of these proteins in autophagy are not well understood. Atg20 and Atg24 each contain a Phox homology domain that facilitates phosphoinositide binding.

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Background: The IMPACT trial demonstrated the safety of a new personalized nomogram for plasma donation and provided an opportunity to explore short- to mid-term impact on repeat donation and deferral rates, and factors affecting these.

Study Design And Methods: In the IMPACT trial, participants were randomized to donate plasma using an established weight-based nomogram (control) versus a new personalized nomogram incorporating height, weight, and hematocrit (experimental). In this exploratory analysis, repeat donations (per donor, by study arm) were analyzed using negative binomial generalized linear regression models and descriptive statistics.

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Background: Source plasma is essential to support the growing demand for plasma-derived medicinal products. Supply is short, with donor availability further limited by the coronavirus disease 2019 (COVID-19) pandemic. This study examined whether a novel, personalized, technology-based nomogram was noninferior with regard to significant hypotensive adverse events (AEs) in healthy donors.

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Article Synopsis
  • In 2008, guidelines were established for researching autophagy, which has since gained significant interest and new technologies, necessitating regular updates to monitoring methods across various organisms.
  • The new guidelines emphasize selecting appropriate techniques to evaluate autophagy while noting that no single method suits all situations; thus, a combination of methods is encouraged.
  • The document highlights that key proteins involved in autophagy also impact other cellular processes, suggesting genetic studies should focus on multiple autophagy-related genes to fully understand these pathways.
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Macroautophagy is a bulk degradation mechanism in eukaryotic cells. Efficiency of an essential step of this process in yeast, Atg8 lipidation, relies on the presence of Atg16, a subunit of the Atg12-Atg5-Atg16 complex acting as the E3-like enzyme in the ubiquitination-like reaction. A current view on the functional structure of Atg16 in the yeast S.

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Autophagy-linked FYVE protein (ALFY) is a large, multidomain protein involved in the degradation of protein aggregates by selective autophagy. The C-terminal FYVE domain of ALFY has been shown to bind phosphatidylinositol 3-phosphate (PI(3)P); however, ALFY only partially colocalizes with other FYVE domains in cells. Thus, we asked if the FYVE domain of ALFY has distinct membrane binding properties compared to other FYVE domains and whether these properties might affect its function in vivo.

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Selective autophagy is the capture of specific cytosolic contents in double-membrane vesicles that subsequently fuse with the vacuole or lysosome, thereby delivering cargo for degradation. Selective autophagy receptors (SARs) mark the cargo for degradation and, in yeast, recruit Atg11, the scaffolding protein for selective autophagy initiation. The mitochondrial protein Atg32 is the yeast SAR that mediates mitophagy, the selective autophagic capture of mitochondria.

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NEMO is a scaffolding protein which plays an essential role in the NF-κB pathway by assembling the IKK-complex with the kinases IKKα and IKKβ. Upon activation, the IKK complex phosphorylates the IκB molecules leading to NF-κB nuclear translocation and activation of target genes. Inhibition of the NEMO/IKK interaction is an attractive therapeutic paradigm for the modulation of NF-κB pathway activity, making NEMO a target for inhibitors design and discovery.

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At low oxygen concentrations, respiration of Pseudomonas aeruginosa (Pa) and other bacteria relies on activity of cytochrome cbb oxidases. A diheme cytochrome c (cyt c) donates electrons to Pa cbb oxidases to enable oxygen reduction and proton pumping by these enzymes. Given the importance of this redox pathway for bacterial pathogenesis, both cyt c and cbb oxidase are potential targets for new antibacterial strategies.

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Cyanobacteria of the and marine genera are the most abundant photosynthetic microbes in the ocean. Intriguingly, the genomes of these bacteria are strongly divergent even within each genus, both in gene content and at the amino acid level of the encoded proteins. One striking exception to this is a 62-amino-acid protein, termed / yper-onserved rotein (PSHCP).

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Unlabelled: Macroautophagy/autophagy is a conserved catabolic recycling pathway involving the sequestration of cytoplasmic components within double-membrane vesicles termed autophagosomes. The autophagy-related (Atg) protein Atg13 is a key member of the autophagy initiation complex. The Atg13 C terminus is an intrinsically disordered region (IDR) harboring a binding site for the vacuolar membrane protein Vac8.

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NEMO is an essential component in the activation of the canonical NF-κB pathway and exerts its function by recruiting the IκB kinases (IKK) to the IKK complex. Inhibition of the NEMO/IKKs interaction is an attractive therapeutic paradigm for diseases related to NF-κB mis-regulation, but a difficult endeavor because of the extensive protein-protein interface. Here we report the high-resolution structure of the unbound IKKβ-binding domain of NEMO that will greatly facilitate the design of NEMO/IKK inhibitors.

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Unlabelled: Mitochondria are targeted for degradation by mitophagy, a selective form of autophagy. In Saccharomyces cerevisiae, mitophagy is dependent on the autophagy receptor, Atg32, an outer mitochondrial membrane protein. Once activated, Atg32 recruits the autophagy machinery to mitochondria, facilitating mitochondrial capture in phagophores, the precursors to autophagosomes.

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