Bayer AG.

The inhibitory glycine receptor (GlyR) is a ligand-gated chloride channel protein that occurs in developmentally regulated isoforms in the vertebrate central nervous system. Monoclonal antibodies (mAbs) against the GlyR distinguish neonatal and adult GlyR proteins by identifying distinct alpha subunit variants within these receptor isoforms. Here, bacterially expressed fusion proteins of the rat GlyR alpha 1 subunit were used to localize the major antigenic epitopes of this protein within its N-terminal 105 amino acids. Synthetic peptides allowed further fine mapping of two mAb binding domains. MAb 2b, specific for the adult alpha 1 subunit, bound to a peptide corresponding to amino acids 1-10, whereas mAb 4a, which recognizes both neonatal and adult GlyR isoforms, reacted with a peptide representing residues 96-105 of the alpha 1 polypeptide. These data define unique and common antigenic epitopes on GlyR alpha subunit variants.

Prone positioning is increasingly used to improve gas exchange in patients with acute lung injury. However, during prone positioning an increase in intraabdominal pressure in these critically ill patients may promote dysfunction of other organs. Therefore, we performed a randomized study in mechanically ventilated patients with acute lung injury to investigate the cardiovascular and renal effects of prone positioning.

Prone positioning in mechanically ventilated patients with acute lung injury, despite a small increase in IAP, does not negatively affect the hepatic capacity to eliminate ICG and gastric intramucosal energy balance when systemic blood flow and oxygenation are improved.

G‐protein βγ‐subunits (Gβγ) are active transmembrane signalling components. Their function recently has been observed to be regulated by the cytosolic protein phosducin. We show here that a small fragment (amino acids 215–232) contained in the C‐terminus of phosducin is sufficient for high‐affinity interactions with Gβγ. Corresponding peptides not only disrupt Gβγ–Gα interactions, as defined by Gβγ‐stimulated GTPase activity of αo, but also other Gβγ‐mediated functions. The NMR structure of a peptide encompassing this region shows a loop exposing the side chains of Glu223 and Tyr224, and peptides with a substitution of either of these amino acids show a complete loss of activity towards Go. Mutation of this Tyr224 to Ala in full‐length phosducin reduced the functional activity of phosducin to that of phosducin's isolated N‐terminus, indicating the importance of this residue within the short, structurally defined C‐terminal segment. This small peptide derived from phosducin may represent a model of a Gβγ inhibitor, and illustrates the potential of small compounds to affect Gβγ functions.