The transmembrane domain of the SNARE protein VAMP2 is highly sensitive to its lipid environment.

Neurotransmitter and hormone exocytosis depends on SNARE protein transmembrane domains and membrane lipids but their interplay is poorly understood. We investigated the interaction of the structure of VAMP2, a vesicular transmembrane SNARE protein, and membrane lipid composition by infrared spectroscopy using either the wild-type transmembrane domain (TMD), VAMP2, or a peptide mutated at the central residues G/C (VAMP2VV) previously identified by us as being critical for exocytosis. Our data show that the structure of VAMP2, in terms of α-helices and β-sheets is strongly influenced by peptide/lipid ratios, by lipid species including cholesterol and by membrane surface charges.

Characterization of neurocalcin delta membrane binding by biophysical methods.

Neurocalcin delta (NCALD) is a member of the neuronal calcium sensors protein family. In the retina, NCALD is expressed by ganglion and amacrine cells. NCALD is composed of 4 EF-hand motifs but only 3 of them may bind calcium.

A Central Small Amino Acid in the VAMP2 Transmembrane Domain Regulates the Fusion Pore in Exocytosis.

Exocytosis depends on cytosolic domains of SNARE proteins but the function of the transmembrane domains (TMDs) in membrane fusion remains controversial. The TMD of the SNARE protein synaptobrevin2/VAMP2 contains two highly conserved small amino acids, G and C, in its central portion. Substituting G and/or C with the β-branched amino acid valine impairs the structural flexibility of the TMD in terms of α-helix/β-sheet transitions in model membranes (measured by infrared reflection-absorption or evanescent wave spectroscopy) during increase in protein/lipid ratios, a parameter expected to be altered by recruitment of SNAREs at fusion sites.

Lipid Selectivity, Orientation, and Extent of Membrane Binding of Nonacylated RP2.

Retinitis pigmentosa 2 (RP2) is an ubiquitary protein of 350 residues. The N-terminus of RP2 contains putative sites of myristoylation and palmitoylation. The dually acylated protein is predominantly localized to the plasma membrane.

A peptide derived from the rotavirus outer capsid protein VP7 permeabilizes artificial membranes.

Biological membranes represent a physical barrier that most viruses have to cross for replication. While enveloped viruses cross membranes through a well-characterized membrane fusion mechanism, non-enveloped viruses, such as rotaviruses, require the destabilization of the host cell membrane by processes that are still poorly understood. We have identified, in the C-terminal region of the rotavirus glycoprotein VP7, a peptide that was predicted to contain a membrane domain and to fold into an amphipathic α-helix.