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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
2004-6-28
pubmed:abstractText
We investigated the mechanisms responsible for severe factor IX (FIX) deficiency in two cross-reacting material (CRM)-negative hemophilia B patients with a mutation in the first and second epidermal growth factor (EGF) domains of FIX (C71Y and C109Y, respectively). We have determined the kinetics of mutant FIX biosynthesis and secretion in comparison with wild-type FIX (FIXwt). In transfected cells, FIXwt was retrieved as two intracellular molecular forms, rapidly secreted into the culture medium. One appeared to be correctly N-glycosylated, and corresponded to a form trafficking between the endoplasmic reticulum (ER) and Golgi apparatus. The other corresponded to the mature form, ready to be secreted, exhibiting correct N-glycosylation and sialylation. In contrast, the two mutants, FIXC71Y and FIXC109Y, were not secreted from the cells and did not accumulate intracellularly. Relative to FIXwt, they were retained longer in the ER and were only N-glycosylated. In addition, the intracellular concentration of the FIX mutants increased when ALLN, an inhibitor of cysteine proteases and of the proteasome degradation pathway, was added to the culture medium. Both the FIX mutants and FIXwt were associated in the ER with the 78-kDa glucose-regulated protein (GRP78/BiP) and calreticulin (CRT), though the amount of CRT associated with the two mutants was twice as strong as with FIXwt. These results strongly suggest that chaperone and lectin molecules act in concert to ensure both proper folding of FIXwt and the retention of mutant molecules.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
1538-7933
pubmed:author
pubmed:issnType
Print
pubmed:volume
2
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1143-54
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Two novel mutations in EGF-like domains of human factor IX dramatically impair intracellular processing and secretion.
pubmed:affiliation
Laboratoire d'Hémobiologie EA 1508, Faculté de Médecine RTH Laennec, Lyon, France. enjolras@laennec.univ-lyon1.fr
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't