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The Drosophila Sterile-20 kinase Slik promotes tissue growth during development by stimulating cell proliferation and by preventing apoptosis. Proliferation within an epithelial sheet requires dynamic control of cellular architecture. Epithelial integrity fails in slik mutant imaginal discs. Cells leave the epithelium and undergo apoptosis. The abnormal behavior of slik mutant cells is due to failure to phosphorylate and activate Moesin, which leads to excess Rho1 activity. This is distinct from Slik's effects on cell proliferation, which are mediated by Raf. Thus Slik acts via distinct pathways to coordinate cell proliferation with epithelial cell behavior during tissue growth.

The cross section for deeply virtual Compton scattering in the reaction ep → eγp has been measured with the ZEUS detector at HERA using integrated luminosities of 95.0 pb −1 of e + p and 16.7 pb −1 of e − p collisions. Differential cross sections are presented as a function of the exchanged-photon virtuality, Q 2 , and the centre-of-mass energy, W , of the γ * p system in the region 5 < Q 2 < 100 GeV 2 and 40 < W < 140 GeV. The measured cross sections rise steeply with increasing W . The measurements are compared to QCD-based calculations.

Caspases are proteases with an active-site cysteine and aspartate specificity in their substrates. They are involved in apoptotic cell death and inflammation, and dysfunction of these enzymes is directly linked to a variety of diseases. Caspase-8 initiates an apoptotic pathway triggered by external stimuli. It was previously characterized in its active inhibitor bound state by crystallography. Here we present the solution structure of the monomeric unprocessed catalytic domain of the caspase-8 zymogen, procaspase-8, showing for the first time the position of the linker and flexibility of the active site forming loops. Biophysical studies of carefully designed mutants allowed disentangling dimerization and processing, and we could demonstrate lack of activity of monomeric uncleaved procaspase-8 and of a processed but dimerization-incompetent mutant. The data provide experimental support in so-far unprecedented detail, and reveal why caspase-8 (and most likely other initiator caspases) needs the dimerization platform during activation.