Molecular imaging of membrane interfaces reveals mode of β-glucosidase activation by saposin C

stephen submitted, created time 1 year 2 months (www.pnas.org)

Acid β-glucosidase (GCase) is a soluble lysosomal enzyme responsible for the hydrolysis of glucose from glucosylceramide and requires activation by the small nonenzymatic protein saposin C (sapC) to gain access to the membrane-embedded glycosphingolipid substrate.

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The SecY translocation complex: convergence of genetics and structure

fiona submitted, created time 1 year 7 months (www.sciencedirect.com)

"All organisms share a requirement for translocation of proteins across membranes. The major mechanism for this process is the universally conserved SecY/Sec61 pathway. Many years of extensive genetic and biochemical analyses identified the components of the SecY/Sec61 pathway, demonstrated that most exported proteins use this route for translocation, and led to understanding of many functions of the components

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Missing-in-metastasis and IRSp53 deform PI(4,5)P2-rich membranes by an inverse BAR domain–like mechanism

julie submitted, created time 1 year 9 months (www.jcb.org)

"The actin cytoskeleton plays a fundamental role in various motile and morphogenetic processes involving membrane dynamics. "

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Nanodiscs unravel the interaction between the SecYEG channel and its cytosolic partner SecA

daphne submitted, created time 1 year 9 months (www.nature.com)

The translocon is a membrane-embedded protein assembly that catalyzes protein movement across membranes. The core translocon, the SecYEG complex, forms oligomers, but the protein-conducting channel is at the center of the monomer. Defining the properties of the SecYEG protomer is thus crucial to understand the underlying function of oligomerization. We report here the reconstitution of a single SecYEG complex into nano-scale lipid bilayers, termed Nanodiscs

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Electron microscopy’s success: structure of a VEGF–VEGF receptor complex determined by electron microscopy

nomad submitted, created time 1 year 10 months (www.nature.com)

Receptor tyrosine kinases are activated upon ligand-induced dimerization. Here we show that the monomeric extracellular domain of vascular endothelial growth factor (VEGF) receptor-2 (VEGFR-2) has a flexible structure. Binding of VEGF to membrane-distal immunoglobulin-like domains causes receptor dimerization and promotes further interaction between receptor monomers through the membrane-proximal immunoglobulin-like domain 7. By this mechanism, ligand-induced dimerization of VEGFR-2 can be communicated across the membrane, activating the intracellular tyrosine kinase domains.

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