Linked Life Data

15478797

Source:http://linkedlifedata.com/resource/pubmed/id/15478797

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2004-10-13
pubmed:abstractText
Earlier, we found that three protein disulfide isomerases (PDI) from Giardia lamblia (gPDI) also have transglutaminase (TGase) activity in vitro. We now show that differentiating Giardia cells contain isopeptide bonds (epsilon(gamma-glutamyl)lysine), the biological product of TGase activity that results in irreversible crosslinking of proteins in vivo. HPLC analyses showed the highest isopeptide bond content in cells encysting for 21 h, indicating an important role for TGase early in encystation. We were not able to detect isopeptide bonds in water-resistant cysts, possibly because they could not be extracted. One of the hallmarks of early encystation is the formation of encystation secretory vesicles (ESV) that transport nascent cyst wall proteins (CWPs) to the outer cell surface. ImmunoEM and live-cell immunofluorescence assays of encysting parasites revealed that gPDIs 1-3 are located in ESV and that gPDI-2 is also novel in that it is localized on the cell surface. Cystamine, a widely used TGase inhibitor, caused a dose-dependent inhibition of ESV formation by 21 h, thereby preventing development of trophozoites into cysts. Since cystamine (0.5-1 mM) inhibited the TGase activity of recombinant gPDIs 1-3 in vitro, PDIs appear to be the physiologic targets of cystamine. We found that when parasites were treated with cystamine, CWPs were not processed normally. These data suggest that TGase-catalyzed reactions may be needed for either the machinery that processes CWP precursors or their recruitment to ESV.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0166-6851
pubmed:author
pubmed:issnType
Print
pubmed:volume
136
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
173-80
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Dependence of Giardia lamblia encystation on novel transglutaminase activity.
pubmed:affiliation
Department of Pathology, Division of Infectious Diseases, UCSD Medical Center, University of California, CTF-C 403, 214 Dickinson Street, San Diego, CA 92103-8416, USA. bdavids@ucsd.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.