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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
2007-8-23
pubmed:abstractText
Variations in the SPINK1 gene (encoding pancreatic secretory trypsin inhibitor (PSTI)) are associated with chronic pancreatitis. We have recently determined the functional consequences of three missense mutations that occurred within the signal peptide sequence of PSTI by Western blotting analysis of wild-type and mutant PSTI expressed in Chinese hamster ovary cells. Here, this approach was extended to analyze seven missense mutations (p.N34S, p.G48E, p.D50E, p.Y54H, p.P55S, p.R65Q and p.R67C) occurring within the mature peptide of PSTI. This analysis enabled us to classify these missense mutations into three categories. The first category comprises the p.N34S and p.P55S polymorphisms, both of which occur in evolutionarily non-conserved residues, involve amino-acid substitutions with similar physicochemical properties, and do not cause any significant reduction in terms of PSTI mature peptide expression. The second category contains only the p.R65Q missense mutation, which occurs in a well-conserved residue, involves the substitution of a positively charged amino acid by a non-charged one, and causes a approximately 60% reduction of protein expression. The third category comprises p.G48E, p.D50E, p.Y54H, and p.R67C, all of which occur in strictly conserved residues, involve charged amino acids, and cause complete or nearly complete loss of PSTI expression. Having excluded the possibility that the reduced protein expression may have resulted from reduced transcription or unstable mRNA, we surmise that these missense mutations probably cause intracellular retention of their respective mutant proteins. This is suggestive of a potential unifying pathological mechanism underlying both the signal peptide and mature peptide mutations.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
1018-4813
pubmed:author
pubmed:issnType
Print
pubmed:volume
15
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
936-42
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Functional analysis of pancreatitis-associated missense mutations in the pancreatic secretory trypsin inhibitor (SPINK1) gene.
pubmed:affiliation
INSERM, U613, Etablissement Français du Sang - Bretagne, Brest 29220, France.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't