Neurodegeneration in Parkinson's disease is correlated with the occurrence of Lewy bodies, intracellular inclusions containing aggregates of the intrinsically disordered protein (IDP) α-Synuclein 1 . The aggregation propensity of α-Synuclein in cells is modulated by specific factors including posttranslational modifications 2,3 , Abelson-kinase-mediated phosphorylation 4,5 and interactions with intracellular machineries such as molecular chaperones, although the underlying mechanisms are unclear [6][7][8] . Here, we systematically characterize the interaction of molecular chaperones with α-Synuclein in vitro as well as in cells at the atomic level. We find that six vastly different molecular chaperones commonly recognize a canonical motif in α-Synuclein, consisting Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use:http://www.nature.com/authors/editorial_policies/license.html#terms *

Nuclear pore complexes (NPCs) are biological nanomachines that mediate the bidirectional traffic of macromolecules between the cytoplasm and nucleus in eukaryotic cells. This process involves numerous intrinsically disordered, barrier-forming proteins known as phenylalanine-glycine nucleoporins (FG Nups) that are tethered inside each pore. The selective barrier mechanism has so far remained unresolved because the FG Nups have eluded direct structural analysis within NPCs. Here, high-speed atomic force microscopy is used to visualize the nanoscopic spatiotemporal dynamics of FG Nups inside Xenopus laevis oocyte NPCs at timescales of ∼100 ms. Our results show that the cytoplasmic orifice is circumscribed by highly flexible, dynamically fluctuating FG Nups that rapidly elongate and retract, consistent with the diffusive motion of tethered polypeptide chains. On this basis, intermingling FG Nups exhibit transient entanglements in the central channel, but do not cohere into a tightly crosslinked meshwork. Therefore, the basic functional form of the NPC barrier is comprised of highly dynamic FG Nups that manifest as a central plug or transporter when averaged in space and time.

Inflammasomes are multiprotein complexes that control the innate immune response by activating caspase-1, thus promoting the secretion of cytokines in response to invading pathogens and endogenous triggers. Assembly of inflammasomes is induced by activation of a receptor protein. Many inflammasome receptors require the adapter protein ASC [apoptosis-associated speck-like protein containing a caspase-recruitment domain (CARD)], which consists of two domains, the N-terminal pyrin domain (PYD) and the C-terminal CARD. Upon activation, ASC forms large oligomeric filaments, which facilitate procaspase-1 recruitment. Here, we characterize the structure and filament formation of mouse ASC in vitro at atomic resolution. Information from cryo-electron microscopy and solid-state NMR spectroscopy is combined in a single structure calculation to obtain the atomic-resolution structure of the ASC filament. Perturbations of NMR resonances upon filament formation monitor the specific binding interfaces of ASC-PYD association. Importantly, NMR experiments show the rigidity of the PYD forming the core of the filament as well as the high mobility of the CARD relative to this core. The findings are validated by structurebased mutagenesis experiments in cultured macrophages. The 3D structure of the mouse ASC-PYD filament is highly similar to the recently determined human ASC-PYD filament, suggesting evolutionary conservation of ASC-dependent inflammasome mechanisms.inflammation | protein structure | protein filament | ASC speck | innate immune response

Conformation and dynamics of a chaperone-client interaction at the atomic level show a basic underlying mechanism.

Together we are strong: A new, robust method allows the measurement of residual chemical shift anisotropies for the determination of conformation and configuration of molecules in organic solvents. The power of the method is shown by the example of estrone and 13‐epi‐estrone (see structures), where only the combined use of residual chemical shift anisotropies and residual dipolar couplings leads to the distinction of the two diastereomers.