Mechanisms of PDZ domain scaffold assembly illuminated by use of supported cell membrane sheets.

PDZ domain scaffold proteins are molecular modules orchestrating cellular signalling in space and time. Here, we investigate assembly of PDZ scaffolds using supported cell membrane sheets, a unique experimental setup enabling direct access to the intracellular face of the cell membrane. Our data demonstrate how multivalent protein-protein and protein-lipid interactions provide critical avidity for the strong binding between the PDZ domain scaffold proteins, PICK1 and PSD-95, and their cognate transmembrane binding partners.

Membrane curvature regulates ligand-specific membrane sorting of GPCRs in living cells.

The targeted spatial organization (sorting) of Gprotein-coupled receptors (GPCRs) is essential for their biological function and often takes place in highly curved membrane compartments such as filopodia, endocytic pits, trafficking vesicles or endosome tubules. However, the influence of geometrical membrane curvature on GPCR sorting remains unknown. Here we used fluorescence imaging to establish a quantitative correlation between membrane curvature and sorting of three prototypic class A GPCRs (the neuropeptide Y receptor Y2, the β adrenergic receptor and the β adrenergic receptor) in living cells.

PDZ domain-mediated interactions of G protein-coupled receptors with postsynaptic density protein 95: quantitative characterization of interactions.

G protein-coupled receptors (GPCRs) constitute the largest family of membrane proteins in the human genome. Their signaling is regulated by scaffold proteins containing PDZ domains, but although these interactions are important for GPCR function, they are still poorly understood. We here present a quantitative characterization of the kinetics and affinity of interactions between GPCRs and one of the best characterized PDZ scaffold proteins, postsynaptic density protein 95 (PSD-95), using fluorescence polarization (FP) and surface plasmon resonance (SPR).

Vinculin's C-terminal region facilitates phospholipid membrane insertion.

The focal adhesion protein vinculin has been implicated in associating with soluble and membranous phospholipids. Here, we investigated the intermolecular interactions of two vinculin tail domains with membrane phospholipids. Previous studies have shown that the tail's unstructured C-terminus affects the mechanical behavior of cells, but not the H3 region.