Tetraspan vesicle membrane proteins (TVPs) comprise a major portion of synaptic vesicle proteins, yet their contribution to the synaptic vesicle cycle is poorly understood. TVPs are grouped in three mammalian gene families: physins, gyrins, and secretory carrier-associated membrane proteins (SCAMPs). In Caenorhabditis elegans, only a single member of each of these families exists. These three nematode TVPs colocalize to the same vesicular compartment when expressed in mammalian cells, suggesting that they could serve overlapping functions. To examine their function, C. elegans null mutants were isolated for each gene, and a triple mutant was generated. Surprisingly, these animals develop normally and exhibit normal neuronal architecture and synaptic contacts. In addition, functions of the motor and sensory systems are normal as determined by pharmacological, chemotaxis, and thermotaxis assays. Finally, direct electrophysiological analysis of the neuromuscular junction revealed no phenotype in the TVP mutants. We therefore conclude that TVPs are not needed for the basic neuronal machinery and instead may contribute to subtle higher order functions.integral membrane proteins ͉ phylogenesis ͉ vesicle trafficking ͉ synaptophysin ͉ synaptogyrin A mong the different synaptic vesicle proteins, those with four membrane-spanning domains [referred to as tetraspan vesicle membrane proteins (TVPs)] are a particularly abundant group whose function in neurotransmission is not understood (1, 2). These polypeptides belong to the physin, gyrin, and secretory carrier-associated membrane protein (SCAMP) families. Members are present in different combinations in synaptic vesicles and also in other transport vesicles of various mammalian cell types (2). Especially puzzling are the mild or even absent phenotypic defects in neurons of knockout mice lacking synaptophysin, synaptogyrin-1, or SCAMP-1 (3-6). A likely explanation is that other members of the same family or even members of other TVP families compensate for loss of a particular TVP. For example, synaptophysin-deficient mice exhibited no neuronal defects except in the photoreceptors that lack the related neuronal physin isoform synaptoporin (7). Furthermore, combined knockouts of the synaptic TVPs synaptophysin and synaptogyrin lead to changes in synaptic plasticity, whereas the single gene inactivations do not (6).Numerous publications propose roles for TVPs for practically all aspects of the synaptic vesicle cycle, including vesicle biogenesis, exocytosis, and endocytotic recycling (2). This notion is supported by the multiple interactions of TVPs with lipids, notably cholesterol (8) or various components of the recycling machinery including soluble N-ethylmaleimide-sensitive fusion attachment protein receptors (SNAREs) (9-11), dynamin (12, 13), adaptor proteins (14), and eps15 homology (EH)-domain proteins (15). In addition, it has been postulated that TVPs are directly responsible for microvesicle formation (8,16,17) and are involved in fusion pore formation (18-21).Thus,...

J. Neurochem. (2010) 115, 585–594. Abstract In mammals, the retina contains a clock system that oscillates independently of the master clock in the suprachiasmatic nucleus and allows the retina to anticipate and to adapt to the sustained daily changes in ambient illumination. Using a combination of laser capture micro‐dissection and quantitative PCR in the present study, the clockwork of mammalian photoreceptors has been recorded. The transcript amounts of the core clock genes Clock, Bmal1, Period1 (Per1), Per3, Cryptochrome2, and Casein kinase Iε in photoreceptors of rat retina have been found to undergo daily changes. Clock and Bmal1 peak with Per1 and Per3 around dark onset, whereas Casein kinase Iε and Cryptochrome2 peak at night. As shown for Clock, Per1, and Casein kinase Iε, the oscillation of transcript amounts results in daily changes of the protein products. The in‐phase oscillation of Clock/Bmal1 with Pers and the rhythmic expression of Casein kinase Iε do not occur in molecular clocks of other tissues including the suprachiasmatic nucleus. Therefore, the findings presented suggest that the photoreceptor clock is unique not only in its position outside the clock hierarchy mastered by the suprachiasmatic nucleus, but also with regard to the intrinsic rhythmic properties of its molecular components.

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This method allows the investigation of the adhesion capability and morphology of individual cells in vitro. Indications of the kind of preservation/reperfusion injury that occurs after treatment with several preservation solutions and the resultant repair behavior can be obtained.

In order to investigate locally produced mediators during the process of organ storage in liver transplantation, we collected the liver preservation solution effluent of 15 transplanted livers and compared it with serum samples taken preoperatively from donor and recipient, as well as 60 min after reperfusion. The mean ischemia time +/- SEM was 10 h 10 min +/- 53 min. Mean concentrations in University of Wisconsin preservation solution effluent were: interleukin-(IL-)1beta 154 +/- 77 pg/ml; IL-1 receptor antagonist (IL-1 ra) 1281 +/- 309 pg/ml; IL-6 412 +/- 90 pg/ml; and for tumor necrosis factor-(TNF-)alpha 74 +/- 21 pg/ml. Cytokine levels in the donors were lower than those detected in the effluent. All measured cytokines showed higher concentrations in the effluent compared to those of the recipient prior to the operation. With respect to a comparison of donor and recipient values, no correlation is evident. Likewise, the ischemic time does not correlate with effluent values. Further development of liver preservation concepts requires information about the state of the graft before reperfusion. Data on cytokine liberation may serve as a helpful tool for the further development of preservation concepts because they enable an estimation of cell activation during preservation.