Linked Life Data

9662024

Source:http://linkedlifedata.com/resource/pubmed/id/9662024

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1998-10-15
pubmed:abstractText
The in vitro differentiation of Trypanosoma brucei from bloodstream to procyclic (insect) forms is accompanied by diminishing variant surface glycoprotein (VSG) and increasing levels of procyclin and phosphoenolpyruvate carboxykinase (PEPCK). In this study, we examined the fate of several glycolytic enzymes of T. brucei during differentiation. We observed a down-regulation of glycosomal phosphoglycerate kinase (gPGK) during differentiation. In contrast, intracellular levels of glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH), aldolase (ALD), and phosphoglucoisomerase (PGI) remained unchanged during differentiation and apparently continued to be synthesized in the procyclic form. To determine the potential role of proteasomes and other proteases during the differentiation process, we tested the effect of lactacystin, a specific inhibitor of proteasome activity, and morpholinourea-Phe-homoPhe-benz-alpha-pyrone (P27), a selective inhibitor of cysteine proteases, on the in vitro differentiation of T. brucei. Cells differentiated normally in the presence of 1 microM lactacystin, which confirmed our previous observation that this differentiation does not require crossing any phase boundaries in the cell cycle (Mutomba and Wang, Mol Biochem Parasitol 1996;80:89-102). But the cells thus differentiated did not increase in number and retained gPGK. Cells differentiated under 2 microM P27 also proceeded at a normal rate but failed to multiply and retained gPGK. However, most of the differentiated cells under 2 microM P27 also retained VSG on the cell membrane surface and expressed higher levels of procyclin suggesting that a cysteine protease(s) may be involved in releasing VSG and partially reducing procyclin during differentiation. This cysteine protease(s) has been tentatively identified in the procyclic cells as a 48 kDa protein through labeling of cysteine protease(s) with a biotinylated P27 homolog K02 (morpholinourea-Phe-homoPhe-vinylsulfone).
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0166-6851
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
93
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
11-22
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
The role of proteolysis during differentiation of Trypanosoma brucei from the bloodstream to the procyclic form.
pubmed:affiliation
Department of Pharmaceutical Chemistry, University of California San Francisco, 94143-0446, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.