Linked Life Data

10318770

Source:http://linkedlifedata.com/resource/pubmed/id/10318770

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
1999-9-9
pubmed:abstractText
The surface coat of procyclic forms of Trypanosoma brucei consists of related, internally repetitive glycoproteins known as EP and GPEET procyclins. Previously we showed that the extracellular domain of GPEET is phosphorylated. We now show that phosphorylation of this glycosylphosphatidylinositol-anchored surface protein can be induced in vitro using a procyclic membrane extract. Using antibodies that recognize either the phosphorylated or unphosphorylated form of GPEET, we analyzed their expression during differentiation of bloodstream forms to procyclic forms. Unphosphorylated GPEET, together with EP, was detected in cell lysates 2-4 hours after initiating differentiation whereas phosphorylated GPEET only appeared after 24 hours. Surface expression of EP and both forms of GPEET occurred after 24-48 hours and correlated with the detection of phosphorylated GPEET on immuno-blots. Electron micrographs showed that unphosphorylated GPEET was predominantly in the flagellar pocket whereas the phosphorylated form was distributed over the cell surface. In contrast, expression of a membrane-bound human placental alkaline phosphatase in procyclic forms caused the accumulation of dephosphorylated GPEET on the cell surface, while the phosphorylated form was restricted to the flagellar pocket. A GPEET-Fc fusion protein, which was retained intracellularly, was not phosphorylated. We propose that unphosphorylated GPEET procyclin is transported to a location close to or at the cell surface, most probably the flagellar pocket, where it becomes phosphorylated. To the best of our knowledge, this study represents the first localization of phosphorylated and unphosphorylated forms of a GPI-anchored protein within a cell.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0021-9533
pubmed:author
pubmed:issnType
Print
pubmed:volume
112 ( Pt 11)
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1785-95
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Phosphorylation of a major GPI-anchored surface protein of Trypanosoma brucei during transport to the plasma membrane.
pubmed:affiliation
Institutes of Biochemistry and Molecular Biology, General Microbiology, and Parasitology, University of Bern, Bern, Switzerland. peter.buetikofer@mci.unibe.ch
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't