SH2-Bbeta is a Rac-binding protein that regulates cell motility.

The Src homology 2 (SH2) domain-containing protein SH2-Bbeta binds to and is a substrate of the growth hormone (GH) and cytokine receptor-associated tyrosine kinase JAK2. SH2-Bbeta also binds, via its SH2 domain, to multiple activated growth factor receptor tyrosine kinases. We have previously implicated SH2-Bbeta in GH and platelet-derived growth factor regulation of the actin cytoskeleton. We extend these findings by establishing a potentiating effect of SH2-Bbeta on GH-dependent cell motility and defining regions of SH2-Bbeta required for this potentiation. Time-lapse video microscopy, phagokinetic, and/or wounding assays demonstrate reduced movement of cells overexpressing SH2-Bbeta lacking an intact SH2 domain because of a point mutation or a C-terminal truncation. An N-terminal proline-rich domain (amino acids 85-106) of SH2-Bbeta is required for inhibition of cellular motility by SH2 domain-deficient mutants. Co-immunoprecipitation experiments indicate that Rac binds to this domain. GH is shown to activate endogenous Rac, and dominant negative mutants of SH2-Bbeta are shown to inhibit membrane ruffling induced by constitutively active Rac. These findings suggest that SH2-Bbeta is an adapter protein that facilitates actin rearrangement and cellular motility by recruiting Rac and potentially Rac-regulating, Rac effector, or other actin-regulating proteins to activated cytokine (e.g. GH) and growth factor receptors.     

Functional differences between TRPC4 splice variants.

Functional characterizations of heterologously expressed TRPC4 have revealed diverse regulatory mechanisms and permeation properties. We aimed to clarify whether these differences result from different species and splice variants used for heterologous expression. Like the murine beta splice variant, rat and human TRPC4beta both formed receptor-regulated cation channels when expressed in HEK293 cells. In contrast, human TRPC4alpha was poorly activated by stimulation of an H(1) histamine receptor. This was not due to reduced expression or plasma membrane targeting, because fluorescent TRPC4alpha fusion proteins were correctly inserted in the plasma membrane. Furthermore, currents through both human TRPC4alpha and TRPC4beta had similar current-voltage relationships and single channel conductances. To analyze the assembly of transient receptor potential channel subunits in functional pore complexes in living cells, a fluorescence resonance energy transfer (FRET) approach was used. TRPC4alpha and TRPC4beta homomultimers exhibited robust FRET signals. Furthermore, coexpressed TRPC4alpha and TRPC4beta subunits formed heteromultimers exhibiting comparable FRET signals. To promote variable heteromultimer assemblies, TRPC4alpha/TRPC4beta were coexpressed at different molar ratios. TRPC4beta was inhibited in the presence of TRPC4alpha with a cooperativity higher than 2, indicating a dominant negative effect of TRPC4alpha subunits in heteromultimeric TRPC4 channel complexes. Finally, C-terminal truncation of human TRPC4alpha fully restored the channel activity. Thus, TRPC4beta subunits form a receptor-dependently regulated homomultimeric channel across various species, whereas TRPC4alpha contains a C-terminal autoinhibitory domain that may require additional regulatory mechanisms.     

Lengthening the aesthetically short nose

An aesthetically short nose is defined as a developmental deformity in which the nose appears foreshortened. It is characterized by a decreased distance from the nasofrontal angle (NFA) to the tip-defining points (TDP) and an increased nasolabial angle with increased nostril show. A method is described and illustrated for lengthening the aesthetically short nose by rotating the nasal tip in an inferior direction. This rotation results in an actual lengthening, as well as an illusion of lengthening of the nose.     

Herbstzug der Sturmschwalbe (Hydrobates pelagicus) in der Meerenge von Gibraltar

Zusammenfassung Entlang eines Transekts über die Meerenge von Gibraltar wurde der Tagzug von Sturmschwalben von August bis Dezember erfaßt. Für einen Durchzug im Mittelmeer brütender Sturmschwalben konnten keine Hinweise gefunden werden; die meisten Vögel scheinen Angehörige der atlantischen Population zu sein. Die Präsenz ist im Oktober/November am höchsten, wenn südwärts ziehende atlantische Brutvögel die Breiten der Straße von Gibraltar erreichen. Insgesamt machten die ins Mittelmeer einfliegenden Vögel 83 % der nach Osten oder Westen fliegenden aus; Schätzungen ergaben für den Tagzug, daß nur 1100–1700 Sturmschwalben das Mittelmeer verließen (hingegen 6300–9500 einflogen). Die mediterrane Brutpopulation ist auf 12 000 Brutpaare zu schätzen.

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Autumn migration of the Storm PetrelHydrobates plelagicus through the Strait of Gibraltar

Storm petrels were recorded along a transect line in the Strait of Gibraltar from August to the middle of November and in December. No hint for migration of the Mediterranean population through the Strait could be revealed. The presence of Storm Petrels is enhanced in October/November. Throughout autumn about 82 % of the Storm Petrels steadily flying east or west flew east. Estimates yield only 1100–1700 storm petrels leaving, but 6300–9500 entering the Mediterranean during daylight, while about 12,000 pairs are known to breed in the Mediterranean.

     

Structural analysis of neutral glycosphingolipids from Ascaris suum adults (Nematoda: Ascaridida)

The neutral glycosphingolipid fraction from adults of the pig parasitic nematode, Ascaris suum, was resolved into four components on thin-layer chromatography. The high-performance liquid chromatography-isolated components were structurally analysed by: methylation analysis; exoglycosidase cleavage; gas-liquid chromatography/mass spectrometry; liquid secondary-ion mass spectrometry; and, in particular, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Their chemical structures were determined as: Glc(β1-1)ceramide, Man(β1-4)Glc(β1-1)ceramide, GlcNAc(β1-3)Man(β1-4)Glc(β1-1)ceramide and Gal(α1-3)GalNAc(β1-4)GlcNAc(β1-3)Man(β1-4)Glc(β1-1)ceramide; and were characterized as belonging to the arthro-series of protostomial glycosphingolipids. No glycosphingolipid component corresponding to ceramide tetrasaccharide was detected during these analyses. The ceramide composition of the parent glycosphingolipids was dominated by the 2-(R)-hydroxy C24:0 fatty acid, cerebronic acid, and C17 sphingoid-bases: 15-methylhexadecasphing-4-enine and 15-methylhexadecaphinganine in approximately equal proportions. The component ceramide monohexoside was characterized by an additional 15-methylhexadecaphytosphingosine. Abbreviations: CDH, ceramide dihexoside; Cer, ceramide; CMH, ceramide monohexoside; CPH, ceramide pentahexoside; CTH, ceramide trihexoside; CTetH, ceramide tetrahexoside; Hex, hexose; HexNAc, N-acetylhexosamine; HPTLC, high-performance thin-layer chromatography; LSIMS, liquid secondary-ion mass spectrometry; MALDI-TOF-MS, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry; N-, Nz- and A-glyco(sphingo)lipids, neutral, neutralzwitterionic and acidic glyco(sphingo)lipids, respectively This revised version was published online in November 2006 with corrections to the Cover Date.     

Interaction network of the ribosome assembly machinery from a eukaryotic thermophile

Ribosome biogenesis in eukaryotic cells is a highly dynamic and complex process innately linked to cell proliferation. The assembly of ribosomes is driven by a myriad of biogenesis factors that shape pre‐ribosomal particles by processing and folding the ribosomal RNA and incorporating ribosomal proteins. Biochemical approaches allowed the isolation and characterization of pre‐ribosomal particles from Saccharomyces cerevisiae, which lead to a spatiotemporal map of biogenesis intermediates along the path from the nucleolus to the cytoplasm. Here, we cloned almost the entire set (～180) of ribosome biogenesis factors from the thermophilic fungus Chaetomium thermophilum in order to perform an in‐depth analysis of their protein–protein interaction network as well as exploring the suitability of these thermostable proteins for structural studies. First, we performed a systematic screen, testing about 80 factors for crystallization and structure determination. Next, we performed a yeast 2‐hybrid analysis and tested about 32,000 binary combinations, which identified more than 1000 protein–protein contacts between the thermophilic ribosome assembly factors. To exemplary verify several of these interactions, we performed biochemical reconstitution with the focus on the interaction network between 90S pre‐ribosome factors forming the ctUTP‐A and ctUTP‐B modules, and the Brix‐domain containing assembly factors of the pre‐60S subunit. Our work provides a rich resource for biochemical reconstitution and structural analyses of the conserved ribosome assembly machinery from a eukaryotic thermophile.     

Long-Term GABA Administration Induces Alpha Cell-Mediated Beta-like Cell Neogenesis

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