Linked Life Data

11073100

Source:http://linkedlifedata.com/resource/pubmed/id/11073100

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2000-11-9
pubmed:abstractText
Fluid-phase endocytosis is stimulated by H-ras-linked growth factor receptors and this stimulation requires activation of rab5. We utilized a GFP-rab5a:wt fusion protein to monitor GFP-rab5a:wt activation in living fibroblasts and in J774 macrophages. Control CHO cells that expressed GFP-rab5a:wt were cultured in serum-free conditions and showed GFP-rab5a:wt localized to endosomal vesicles with a mean diameter of 0.3 +/- 0.1 microm. Endosome fusion, membrane ruffling, and pinosome formation were rarely detected in these cells. Coexpression of H-ras:G12V, a constitutively active H-ras mutant that activates rab5a, in cells resulted in marked enlargement of labeled endosomes (mean diameter 0.7 +/- 0.2 microm) and large numbers of giant GFP-rab5a:wt-positive endosomes were present. Time-lapse recordings showed abundant fusion among giant labeled endosomes, and membrane ruffling and pinosome formation were commonly observed. Alterations in GFP-rab5a:wt endosome structure and activity in cells expressing H-ras:G12V were linked to rab5a activation because these changes were identical to those found in cells expressing GFP-rab5a:Q79L, a constitutively activated rab5a mutant. Furthermore, cells co-expressing H-ras:G12V and GFP-rab5a:S34N, an inactive rab5a mutant, exhibited no evidence of H-ras:G12V-induced endosome enlargement. To observe changes in endosome structure and activity that directly followed activation of GFP-rab5a:wt, we performed time-lapse recordings of cells cultured overnight in serum-free media after addition of EGF. EGF caused a rapid increase in endosome fusion and in membrane ruffling activity. Membrane ruffling was often associated with GFP-rab5a:wt-positive vesicle (pinosome) formation at the base of membrane ruffles. Endosome and pinosome fusion were common in EGF-stimulated cells. Phagocytosis is also regulated by GFP-rab5a:wt. J774 macrophages that expressed GFP-rab5a:wt showed transiently activation and recruitment of GFP-rab5a:wt to newly formed phagosomes that contained rhodamine-labeled Escherichia coli. These studies show that GFP-rab5a:wt activation results in dynamic alterations in the structure and activity of the early endosomal and early phagosomal elements.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0741-5400
pubmed:author
pubmed:issnType
Print
pubmed:volume
68
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
627-32
pubmed:dateRevised
2005-11-17
pubmed:meshHeading
pubmed-meshheading:11073100-Animals, pubmed-meshheading:11073100-CHO Cells, pubmed-meshheading:11073100-Cell Membrane, pubmed-meshheading:11073100-Cricetinae, pubmed-meshheading:11073100-Endocytosis, pubmed-meshheading:11073100-Endosomes, pubmed-meshheading:11073100-Epidermal Growth Factor, pubmed-meshheading:11073100-Escherichia coli, pubmed-meshheading:11073100-Fibroblasts, pubmed-meshheading:11073100-Fluorescent Dyes, pubmed-meshheading:11073100-Green Fluorescent Proteins, pubmed-meshheading:11073100-Humans, pubmed-meshheading:11073100-Indicators and Reagents, pubmed-meshheading:11073100-Intracellular Membranes, pubmed-meshheading:11073100-Luminescent Proteins, pubmed-meshheading:11073100-Macrophages, pubmed-meshheading:11073100-Microscopy, Confocal, pubmed-meshheading:11073100-Phagocytosis, pubmed-meshheading:11073100-Recombinant Fusion Proteins, pubmed-meshheading:11073100-Rhodamines, pubmed-meshheading:11073100-rab5 GTP-Binding Proteins, pubmed-meshheading:11073100-ras Proteins
pubmed:year
2000
pubmed:articleTitle
Dynamics of rab5 activation in endocytosis and phagocytosis.
pubmed:affiliation
Department of Cell Biology and Physiology, Washington University, School of Medicine, St. Louis, Missouri 63110, USA.
pubmed:publicationType
Journal Article