Velocity distributions of sputtered excited atoms

The first direct measurements are reported of the velocity distributions of sputtered atoms in excited states with electronic configurations completely different from the ground state. In contrast to previous work, the measured distributions for both the singlet and triplet metastable D states of Ba atoms showed no energy thresholds and had most probable energies similar to those of sputtered ground-state atoms.Peer reviewedElectrical and Computer Engineerin

Analysis of the key elements of FFAT-like motifs identifies new proteins that potentially bind VAP on the ER, including two AKAPs and FAPP2.

Two phenylalanines (FF) in an acidic tract (FFAT)-motifs were originally described as having seven elements: an acidic flanking region followed by 6 residues (EFFDA-E). Such motifs are found in several lipid transfer protein (LTP) families, and they interact with a protein on the cytosolic face of the ER called vesicle-associated membrane protein-associated protein (VAP). Mutation of which causes ER stress and motor neuron disease, making it important to determine which proteins bind VAP. Among other proteins that bind VAP, some contain FFAT-like motifs that are missing one or more of the seven elements. Defining how much variation is tolerated in FFAT-like motifs is a preliminary step prior to the identification of the full range of VAP interactors

A Late Pleistocene palaeoclimate record based on mineral magnetic properties of the entrance facies sediments of Kulna Cave, Czech Republic

Kulna Cave is located in the Moravian Karst, a well-developed karstic region formed in Devonian limestones in the eastern part of the Czech Republic. The entrance facies sediments in the cave consist of interbedded layers of silts (loess) and clay-rich silts (loam) that were either directly blown into the cave entrance or redeposited in the cave by slope processes during the Last Glacial Stage. The layers of loess and loam overlie fluvial sands and gravels deposited during the Last Interglacial. Previous research at Kulna concentrated on the archaeology, palaeontology and dendrology of these entrance facies sediments. From these data, palaeoenvironmental conditions in the vicinity of the cave were reconstructed. Our results suggest that susceptibility variations and in particular variations in pedogenic susceptibility yield a more detailed record of the palaeoenvironmental conditions at the cave during the Last Glacial Stage. Magnetic susceptibility (X) was measured on approximately 700 samples collected throughout three well-studied profiles in the cave entrance. The x record is well defined and correlates from one profile to another. Mineral magnetic measurements [FD, ARM /SIRM, S-ratio, x(T)] suggest that x variations in the Kulna sediments from the Last Glacial Stage are controlled by the concentration of magnetite and/or maghemite formed during pedogenesis. After the removal of the effects of fine carbonate debris and detrital ferromagnetic minerals on the bulk x record, we obtained a record of pedogenic susceptibility (xp) that serves to quantify the concentration of magnetic minerals formed during pedogenesis. Therefore, xp can be thought of as a proxy reflecting the intensity of pedogenesis, which in turn is controlled by climate. Our xp record is also in good agreement with the median grain size record of the Kulna sediments (another proxy for climatic change). We suggest that in the case of Kulna, xp is more sensitive to climate change than bulk x. The Kulna pedogenic susceptibility record shows variations on both long and short timescales. The long-term trends are in good agreement with the deep-sea SPECMAP record, while the short-term oscillations correlate well with rapid changes in the North Atlantic sea surface temperatures. Our results suggest that Central European climate during the Last Glacial Stage was strongly controlled by the sea surface temperatures in the North Atlantic. Short-term warmer events and perhaps higher precipitation over the mid-continent increased the intensity of pedogenesis. Given the number of independent climate proxies determined from the entrance facies of the cave and their high resolution, Kulna is an extremely important site for studying Late Pleistocene climate

FCHO controls AP2's initiating role in endocytosis through a Ptdlns(4,5)P-2-dependent switch

Clathrin-mediated endocytosis (CME) is the main mechanism by which mammalian cells control their cell surface proteome. Proper operation of the pivotal CME cargo adaptor AP2 requires membrane-localized Fer/Cip4 homology domain-only proteins (FCHO). Here, live-cell enhanced total internal reflection fluorescence-structured illumination microscopy shows that FCHO marks sites of clathrin-coated pit (CCP) initiation, which mature into uniform-sized CCPs comprising a central patch of AP2 and clathrin corralled by an FCHO/Epidermal growth factor potential receptor substrate number 15 (Eps15) ring. We dissect the network of interactions between the FCHO interdomain linker and AP2, which concentrates, orients, tethers, and partially destabilizes closed AP2 at the plasma membrane. AP2's subsequent membrane deposition drives its opening, which triggers FCHO displacement through steric competition with phosphatidylinositol 4,5-bisphosphate, clathrin, cargo, and CME accessory factors. FCHO can now relocate toward a CCP's outer edge to engage and activate further AP2s to drive CCP growth/maturation