RIM and RIM-Binding Protein Localize Synaptic CaV2 Channels to Differentially Regulate Transmission in Neuronal Circuits.

At chemical synapses, voltage-gated Ca channels (VGCCs) translate electrical signals into a trigger for synaptic vesicle (SV) fusion. VGCCs and the Ca microdomains they elicit must be located precisely to primed SVs to evoke rapid transmitter release. Localization is mediated by Rab3-interacting molecule (RIM) and RIM-binding proteins, which interact and bind to the C terminus of the CaV2 VGCC α-subunit.

Cryo-EM structure of cell-free synthesized human histamine 2 receptor/G complex in nanodisc environment.

Here we describe the cryo-electron microscopy structure of the human histamine 2 receptor (HR) in an active conformation with bound histamine and in complex with G heterotrimeric protein at an overall resolution of 3.4 Å. The complex was generated by cotranslational insertion of the receptor into preformed nanodisc membranes using cell-free synthesis in E.

Transfer mechanism of cell-free synthesized membrane proteins into mammalian cells.

Nanodiscs are emerging to serve as transfer vectors for the insertion of recombinant membrane proteins into membranes of living cells. In combination with cell-free expression technologies, this novel process opens new perspectives to analyze the effects of even problematic targets such as toxic, hard-to-express, or artificially modified membrane proteins in complex cellular environments of different cell lines. Furthermore, transferred cells must not be genetically engineered and primary cell lines or cancer cells could be implemented as well.

Cell-Free Expression of GPCRs into Nanomembranes for Functional and Structural Studies.

Despite their importance in many essential physiological processes of living cells, G protein-coupled receptors (GPCRs) are often difficult to express and purify in sufficient quality and quantity. We demonstrate cell-free protein synthesis as an interesting alternative to classical cell-based expression systems. We focus on a recently developed detergent-free expression mode by co-translational integration of nascent GPCRs into provided nanodisc membranes of defined composition.

Ingestion and Toxicity of Polystyrene Microplastics in Freshwater Bivalves.

The ubiquity of microplastics in aquatic ecosystems has raised concerns over their interaction with biota. However, microplastics research on freshwater species, especially mollusks, is still scarce. We, therefore, investigated the factors affecting microplastics ingestion in the freshwater mussel Dreissena polymorpha.