Linked Life Data

9694898

Source:http://linkedlifedata.com/resource/pubmed/id/9694898

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
33
pubmed:dateCreated
1998-9-14
pubmed:abstractText
The present study was undertaken to identify and characterize molecular chaperones that assist in the folding of apolipoprotein (apo) B, a secretory protein that requires assembly with lipids (lipidation) for its secretion. Both HepG2 cells, normally secreting full-length apoB (apoB-100), and C127 cells transfected to secrete truncated forms of apoB, apoB-41, apoB-29, and apoB-17, respectively, were employed. C127 cells were used to determine whether chaperone binding is dependent on apoB lipidation as they secrete both unlipidated and lipidated apoB forms despite their lack of microsomal triglyceride transfer protein (MTP), which mediates lipidation of apoB in HepG2 cells. The endoplasmic reticulum (ER)-resident molecular chaperones GRP94, calreticulin, and ERp72 were co-immunoprecipitated with apoB-100 from HepG2 cell lysates following cross-linking of proteins in living cells. The same chaperones including BiP/GRP78 were also associated with all truncated forms of apoB. Sequential immunoprecipitation with antibodies to MTP and apoB revealed the presence of ternary complexes containing apoB-100, MTP, and ERp72. However, MTP is not obligatory for the binding of ERp72 as it was associated with all truncated forms of apoB in C127 cells that lack MTP. The interactions between apoB-100 and ERp72 or GRP94 persisted for at least 2 h following a 30-min pulse. Thus, BiP/GRP78, calreticulin, ERp72, and GRP94 may participate in critical steps in the folding of apoB before any substantial lipidation occurs. ERp72 and GRP94 may also mediate the folding of more advanced folding intermediates and/or target the misfolded underlipidated pool of apoB for degradation.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
14
pubmed:volume
273
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
21368-73
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Multiple molecular chaperones interact with apolipoprotein B during its maturation. The network of endoplasmic reticulum-resident chaperones (ERp72, GRP94, calreticulin, and BiP) interacts with apolipoprotein b regardless of its lipidation state.
pubmed:affiliation
Department of Biophysics, Center for Advanced Biomedical Research, Boston University School of Medicine, Boston, Massachusetts 02118, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.