The fusion of myoblasts to myotubes requires an endogenous soluble metalloendoprotease. To determine whether this protease is released by fusing myoblasts, or stays within the cell, we examined the effects of membrane-impermeant and a membrane-permeant metalloendoprotease inhibitors. Membrane-permeant 1,10-phenanthroline, and membrane-impermeant bathophenanthroline disulfonic acid both inhibited soluble metalloendoprotease activity in homogenized myoblasts with equal potency. However, while 1,10-phenanthroline inhibited fusion, bathophenanthroline disulfonic acid had no effect. In addition, metalloendoprotease activity could not be detected in the media of fusing myoblasts, but was in the cells. These observations support the conclusion that the soluble metalloendoprotease required in fusion remains within the myoblast.
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http://dx.doi.org/10.1016/s0006-291x(87)80145-6 | DOI Listing |
Biochem Biophys Res Commun
January 2010
Department of Biophysics, Federal University of São Paulo, São Paulo 04044-020, Brazil.
In the present study, soluble, functionally-active, recombinant human mitochondrial intermediate peptidase (hMIP), a mitochondrial metalloendoprotease, was expressed in a prokaryotic system. The hMIP fusion protein, with a poly-His-tag (6x His), was obtained by cloning the coding region of hMIP cDNA into the pET-28a expression vector, which was then used to transform Escherichia coli BL21 (DE3) pLysS. After isolation and purification of the fusion protein by affinity chromatography using Ni-Sepharose resin, the protein was purified further using ion exchange chromatography with a Hi-trap resource Q column.
View Article and Find Full Text PDFEur J Neurosci
April 1999
Instituto de Microbiolgía Bioquímica, Consejo Superior de Investigaciones Científicas-Universidad de Salamanca, Spain.
The ectodomain of the neurotrophin receptor TrkA has been recovered as a soluble fragment from the culture media of cells by a process that involves endoproteolytic cleavage. This cleavage may be upregulated by several treatments, including NGF treatment or protein kinase C activation. In this report we have investigated the cellular site and proteolytic activities involved in TrkA cleavage, and the effects of ectodomain truncation on signalling.
View Article and Find Full Text PDFEMBO J
July 1997
Department of Medical Microbiology and Immunology, University of Wisconsin-Madison Medical School, 53706, USA.
Using transformed procyclic trypanosomes, the synthesis, intracellular transport and secretion of wild-type and mutant variant surface glycoprotein (VSG) is characterized. We find no impediment to the expression of this bloodstream stage protein in insect stage cells. VSG receives a procyclic-type phosphatidylinositol-specific phospholipase C-resistant glycosyl phosphatidylinositol (GPI) anchor, dimerizes and is N-glycosylated.
View Article and Find Full Text PDFEMBO J
December 1993
Howard Hughes Medical Institute, Yale University Medical School, New Haven, CT 06510.
The anaerobic bacterium Clostridium botulinum produces several related neurotoxins that block exocytosis of synaptic vesicles in nerve terminals and that are responsible for the clinical manifestations of botulism. Recently, it was reported that botulinum neurotoxin type B as well as tetanus toxin act as zinc-dependent proteases that specifically cleave synaptobrevin, a membrane protein of synaptic vesicles (Link et al., Biochem.
View Article and Find Full Text PDFJ Biol Chem
September 1993
Department of Pharmacology, Yale University Medical School, New Haven, Connecticut 06510.
Tetanus toxin is a potent inhibitor of neurotransmitter release, which acts as an intracellular metalloendoprotease that selectively cleaves synaptobrevin, a major membrane protein of synaptic vesicles. Recently, synaptobrevin has been found to form an ATP-dependent complex with N-ethylmaleimide-sensitive fusion protein (NSF) and soluble NSF attachment protein, which are known to function in endosome fusion. Furthermore, a highly homologous isoform of synaptobrevin, named cellubrevin, was identified that is expressed in virtually all tissues in the endocytic pathway and is cleaved by tetanus toxin light chain in vitro, suggesting that cellubrevin may have a general function in intracellular fusion events.
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