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Atg101 is an essential component of the autophagy-initiating ULK complex in higher eukaryotes, but it is absent from the functionally equivalent Atg1 complex in budding yeast. Here, we report the crystal structure of the fission yeast Atg101-Atg13 complex. Atg101 has a Hop1, Rev7 and Mad2 (HORMA) architecture similar to that of Atg13. Mad2 HORMA has two distinct conformations (O-Mad2 and C-Mad2), and, intriguingly, Atg101 resembles O-Mad2 rather than the C-Mad2-like Atg13. Atg13 HORMA from higher eukaryotes possesses an inherently unstable fold, which is stabilized by Atg101 via interactions analogous to those between O-Mad2 and C-Mad2. Mutational studies revealed that Atg101 is responsible for recruiting downstream factors to the autophagosome-formation site in mammals via a newly identified WF finger. These data define the molecular functions of Atg101, providing a basis for elucidating the molecular mechanisms of mammalian autophagy initiation by the ULK complex.

Background ALG-2 (a gene product of PDCD6) belongs to the penta-EF-hand (PEF) protein family and Ca2+-dependently interacts with various intracellular proteins including mammalian Alix, an adaptor protein in the ESCRT system. Our previous X-ray crystal structural analyses revealed that binding of Ca2+ to EF3 enables the side chain of R125 to move enough to make a primary hydrophobic pocket (Pocket 1) accessible to a short fragment of Alix. The side chain of F122, facing a secondary hydrophobic pocket (Pocket 2), interacts with the Alix peptide. An alternatively spliced shorter isoform, designated ALG-2ΔGF122, lacks Gly121Phe122 and does not bind Alix, but the structural basis of the incompetence has remained to be elucidated. Results We solved the X-ray crystal structure of the PEF domain of ALG-2ΔGF122 in the Ca2+-bound form and compared it with that of ALG-2. Deletion of the two residues shortened α-helix 5 (α5) and changed the configuration of the R125 side chain so that it partially blocked Pocket 1. A wall created by the main chain of 121-GFG-123 and facing the two pockets was destroyed. Surprisingly, however, substitution of F122 with Ala or Gly, but not with Trp, increased the Alix-binding capacity in binding assays. The F122 substitutions exhibited different effects on binding of ALG-2 to other known interacting proteins, including TSG101 (Tumor susceptibility gene 101) and annexin A11. The X-ray crystal structure of the F122A mutant revealed that removal of the bulky F122 side chain not only created an additional open space in Pocket 2 but also abolished inter-helix interactions with W95 and V98 (present in α4) and that α5 inclined away from α4 to expand Pocket 2, suggesting acquirement of more appropriate positioning of the interacting residues to accept Alix. Conclusions We found that the inability of the two-residue shorter ALG-2 isoform to bind Alix is not due to the absence of bulky side chain of F122 but due to deformation of a main-chain wall facing pockets 1 and 2. Moreover, a residue at the position of F122 contributes to target specificity and a smaller side chain is preferable for Alix binding but not favored to bind annexin A11.

High power durable electrodes have been successfully grown on 38.5° rotated Y-X LiTaO3 piezoelectric substrates featuring epitaxial Al films with a pseudo-homoepitaxial Ti intermediate layer. We found that a two-step process sequence in the deposition temperature of an intermediate layer could make it possible for an Al/Ti structure to grow epitaxially on low-cut-angle Y-X LiTaO3. Specified epitaxial relationship was Al(111)//Ti(001)//LiTaO3(001). Duplexers with epitaxial Al electrodes had a breakdown power above 6 W and more than ten times longer lifetime in contrast to filters with polycrystalline electrodes of which the breakdown power is 3.4 W. Epitaxial electrodes with extremely less grain boundary can improve power durability because self-diffusion of Al atoms occurs mainly in the grain boundary of the film. Material variation of epitaxial electrodes will be discussed as well.

We report the synthesis and characterization of a soluble metal complex polymer for electroluminescent (EL) applications. The polymer was prepared by the reaction of a zinc Schiff base with 4,4′-diphenylmethane-diisocyanate. The polymer is amorphous and with glass transition temperature of 156 °C and is soluble in common organic solvents such as chloroform, tetrahydrofuran (THF), and N-methylpyrrolidinone (NMP). High optical quality films were obtained by spin-coating the polymer solution of THF. The zinc Schiff base, and the polyurethane (PU) shows strong photoluminescence under a UV-lamp illumination. Single and double layer EL devices consisting ITO/hole transfer layer (HTL)/PU/Al have been fabricated and characterized. The results indicated that the complex polymer could act as both electron transport and emissive layers for EL devices.

Polyimide-silica hybrid materials were prepared via a modified sol-gel, high pressure-thermal polymerization procedure. Precursor monomer salts were made from ethanol soluble 2,5- diethoxycarboxyl terephthalic acid (p-PME) and either a disiloxanediamine, an aliphatic diamine (1,9 diaminononane) or combinations of the two. Solutions of tetramethoxysilane (TMOS) and monomer salt were transformed into a gel, dehydrated, and the resulting powders were subjected to high pressure and thermal polymerization and transformed into a polyimide-silica composite. By varying the TMOS content, and/or the siloxane to aliphatic diamine ratio., composites of 0 to 100 wt% SiO2 were made. The silica morphology changed significantly with siloxane/aliphatic PI ratio. Reaction mechanisms, thermal and physical properties and composite morphologies are discussed.