Search results for "SNARE"
showing 6 items of 16 documents
Regulation of the hDlg/hScrib/Hugl-1 tumour suppressor complex.
2008
The proper function of the Scribble tumour suppressor complex is dependent upon the correct localisation of its components. Previously we observed dynamic relocalisation of the hDlg component under conditions of osmotic stress. We now show that the other two components of the complex, hScrib and Hugl-1 display similar patterns of expression. We demonstrate, by shRNA ablation of hScrib expression, that hDlg and Hugl-1 are in part dependent upon hScrib for their correct localization. However under conditions of osmotic stress this apparent dependency no longer exists: hDlg and Hugl-1 localise to cell membranes independently of hScrib. We also demonstrate an interaction between the three compo…
Axon-glia interaction and membrane traffic in myelin formation
2014
In vertebrate nervous systems myelination of neuronal axons has evolved to increase conduction velocity of electrical impulses with minimal space and energy requirements. Myelin is formed by specialized glial cells which ensheath axons with a lipid-rich insulating membrane. Myelination is a multi-step process initiated by axon-glia recognition triggering glial polarization followed by targeted myelin membrane expansion and compaction. Thereby, a myelin sheath of complex subdomain structure is established. Continuous communication between neurons and glial cells is essential for myelin maintenance and axonal integrity. A diverse group of diseases, from multiple sclerosis to schizophrenia, ha…
Synaptobrevin cleavage by the tetanus toxin light chain is linked to the inhibition of exocytosis in chromaffin cells
1994
AbstractExocytosis of secretory granules by adrenal chromaffin cells is blocked by the tetanus toxin light chain in a zinc specific manner. Here we show that cellular synaptobrevin is almost completely degraded by the tetanus toxin light chain within 15 min. We used highly purified adrenal secretory granules to show that synaptobrevin, which can be cleaved by the tetanus toxin light chain, is localized in the vesicular membrane. Proteolysis of synaptobrevin in cells and in secretory granules is reversibly inhibited by the zinc chelating agent dipicolinic acid. Moreover, cleavage of synaptobrevin present in secretory granules by the tetanus toxin light chain is blocked by the zinc peptidase …
Fertility and Polarized Cell Growth Depends on eIF5A for Translation of Polyproline-Rich Formins in Saccharomyces cerevisiae
2014
eIF5A is an essential and evolutionary conserved translation elongation factor, which has recently been proposed to be required for the translation of proteins with consecutive prolines. The binding of eIF5A to ribosomes occurs upon its activation by hypusination, a modification that requires spermidine, an essential factor for mammalian fertility that also promotes yeast mating. We show that in response to pheromone, hypusinated eIF5A is required for shmoo formation, localization of polarisome components, induction of cell fusion proteins, and actin assembly in yeast. We also show that eIF5A is required for the translation of Bni1, a proline-rich formin involved in polarized growth during …
Tissue expression of the vesicle protein pantophysin
1999
The cell-type restricted expression of cytoplasmic microvesicle membrane protein isoforms may be a consequence of the functional adaptation of these vesicles to the execution of specialized processes in cells of different specialization. To characterize the expression of the vesicle protein pantophysin, an isoform of the synaptic vesicle proteins synaptophysin and synaptoporin, we have prepared and characterized antibodies useful for the immunological detection of pantophysin in vitro and in situ. Using these reagents, we show by immunoblot analyses that pantophysin expression is not homogeneous but differs significantly between various bovine tissues. Furthermore, these differences are not…
A single mutation in the recombinant light chain of tetanus toxin abolishes its proteolytic activity and removes the toxicity seen after reconstituti…
1994
Specific proteolysis by the tetanus toxin light chain of a vesicle-associated membrane protein (VAMP) involved in exocytosis is thought to underlie its intracellular blockade of neurotransmitter release. To substantiate this mechanism, recombinant light chain was expressed as a maltose binding protein-light chain fusion product in Escherichia coli. After purification of affinity chromatography and cleavage with factor Xa, the resultant light chain was isolated and its identity confirmed by Western blotting and N-terminal sequencing. It exhibited activity similar to that of the native light chain in proteolyzing its target in isolated bovine small synaptic vesicles and in hydrolyzing a 62-re…