Showing papers by "María Isabel Colombo published in 1994"
TL;DR: It is concluded that endosomes can fuse by two mechanisms, one that has an absolute requirement for calcium and is probably mediated by annexins, and another that does not require calcium.
114 citations
TL;DR: It is believed that Rab5 function requires protein-protein interactions with Rab5-specific regulators and effectors, and some of these interactions are disrupted by Rab5:S34N and Rab4:N133I, which are dominant inhibitors of endocytosis.
101 citations
TL;DR: It is shown here that Rab5, in the GTP gamma S (guanosine 5'-O-(thiotriphosphate))-bound form, fully supports in vitro endosome fusion, indicating that GTP hydrolysis is not required, whereas Rab5:S34N and Rab 5:N133I, mutants unable to bind GTP, are potent inhibitors of endosomes fusion.
96 citations
TL;DR: Findings indicate a role for Gs in either the mechanism or the regulation of fusion among endosomes and raise the possibility that signal transduction through cytoplasmic domains of receptors may participate in theregulation of endocytic trafficking.
65 citations
TL;DR: Aluminum fluoride (AIF), a reagent that activates trimeric G proteins, is used as a tool to study the involvement of this family of GTPases in the regulation of endocytosis in intact cells and indicates that AIF inhibits fusion of early endosomes with an intracellular proteolytic compartment.
Abstract: SummaryIt is now well established that GTP-binding proteins are important regulators of vesicular transport. Recent work has shown that multiple GTPases (both monomeric and heterotrimeric) are required for trafficking. In the present study we have used aluminum fluoride (AIF), a reagent that activates trimeric G proteins, as a tool to study the involvement of this family of GTPases in the regulation of endocytosis in intact cells. Our results indicate that AIF Inhibits fusion of early endosomes with an intracellular proteolytic compartment. Using the mixing of sequentially internalized ligands as a measure of endocytosis, we found that AIF inhibited endocytic transport as assessed by both biochemical and morphological methods. Taken together these results suggest that AIF affects membrane fusion, a common step in vesicular transport. To further examine the effects of AIF we tested this compound in a cell-free assay that reconstitutes fusion among endosomes. AIF affected endosomal fusion in a different way...
11 citations