Publications by authors named "Giovanni Howells"

Article Synopsis
  • - The proteasome is essential for maintaining cellular balance by breaking down damaged or unnecessary proteins, and its regulation—especially through proteins with the HbYX motif—is crucial for understanding its function.
  • - ProEnd is a new database created to identify and catalog proteins containing the HbYX motif from a vast analysis of around 73 million proteins across 22,000 reference proteomes, revealing the motif's importance and evolutionary conservation in many organisms, particularly in viruses.
  • - The database also validated two newly discovered HbYX proteins that interact with the proteasome, with one of them shown to activate it, paving the way for new research and potential therapies for diseases like neurodegenerative disorders and cancer.
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The proteasome plays a crucial role in cellular homeostasis by degrading misfolded, damaged, or unnecessary proteins. Understanding the regulatory mechanisms of proteasome activity is vital, particularly the interaction with activators containing the hydrophobic-tyrosine-any amino acid (HbYX) motif. Here, we present ProEnd, a comprehensive database designed to identify and catalog HbYX motif-containing proteins across the tree of life.

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Proteasome dysfunction is implicated in the pathogenesis of neurodegenerative diseases and age-related proteinopathies. Using a model, we demonstrate that 20S proteasome hyperactivation, facilitated by 20S gate-opening, accelerates the targeting of intrinsically disordered proteins. This leads to increased protein synthesis, extensive rewiring of the proteome and transcriptome, enhanced oxidative stress defense, accelerated lipid metabolism, and peroxisome proliferation.

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Neurotransmitter release of synaptic vesicles relies on the assembly of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex, consisting of syntaxin and SNAP-25 on the plasma membrane and synaptobrevin on the synaptic vesicle. The formation of the SNARE complex progressively zippers towards the membranes, which drives membrane fusion between the plasma membrane and the synaptic vesicle. However, the underlying molecular mechanism of SNARE complex regulation is unclear.

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