Linked Life Data

15274640

Source:http://linkedlifedata.com/resource/pubmed/id/15274640

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
30
pubmed:dateCreated
2004-7-27
pubmed:abstractText
Because of the lack of protein turnover in fiber cells of the ocular lens, Aquaporin 0 (AQP0), the most abundant membrane protein in the lens, undergoes extensive post-translational modification with fiber cell age. To map the distribution of modified forms of AQP0 within the lens, normal human lenses ranging in age from 34 to 38 were concentrically dissected into several cortical and nuclear sections. Membrane proteins still embedded in the membranes were digested with trypsin, and the resulting C-terminal peptides of AQP0 were analyzed by HPLC tandem mass spectrometry, permitting the identification of modifications and estimation of their abundance. Consistent with earlier reports, the major phosphorylation site was Ser 235, and the major sites of backbone cleavage occurred at residues 246 and 259. New findings suggest that cleavage at these sites may be a result of nonenzymatic truncation at asparagine residues. In addition, this approach revealed previously undetected sites of truncation at residues 249, 260, 261, and 262; phosphorylation at Ser 231 and to a lower extent at Ser 229; and racemization/isomerization of l-Asp 243 to d-Asp and d-iso-Asp. The spatial distribution of C-terminally modified AQP0 within the lens indicated an increase in truncation and racemization/isomerization with fiber cell age, whereas the level of Ser 235 phosphorylation increased from the outer to inner cortex but decreased in the nucleus. Furthermore, the remarkably similar pattern and distribution of truncation products from lenses from three donors suggest specific temporal mechanisms for the modification of AQP0.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
3
pubmed:volume
43
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
9856-65
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:15274640-Adult, pubmed-meshheading:15274640-Amino Acid Sequence, pubmed-meshheading:15274640-Aquaporins, pubmed-meshheading:15274640-Asparagine, pubmed-meshheading:15274640-Cell Aging, pubmed-meshheading:15274640-Chromatography, Liquid, pubmed-meshheading:15274640-Eye Proteins, pubmed-meshheading:15274640-Humans, pubmed-meshheading:15274640-Hydrolysis, pubmed-meshheading:15274640-Lens, Crystalline, pubmed-meshheading:15274640-Male, pubmed-meshheading:15274640-Membrane Glycoproteins, pubmed-meshheading:15274640-Molecular Sequence Data, pubmed-meshheading:15274640-Peptide Fragments, pubmed-meshheading:15274640-Phosphorylation, pubmed-meshheading:15274640-Protein Conformation, pubmed-meshheading:15274640-Protein Processing, Post-Translational, pubmed-meshheading:15274640-Sequence Deletion, pubmed-meshheading:15274640-Spectrometry, Mass, Electrospray Ionization, pubmed-meshheading:15274640-Spectrometry, Mass, Matrix-Assisted Laser..., pubmed-meshheading:15274640-Trypsin
pubmed:year
2004
pubmed:articleTitle
Post-translational modifications of aquaporin 0 (AQP0) in the normal human lens: spatial and temporal occurrence.
pubmed:affiliation
Department of Cell and Molecular Pharmacology, Medical University of South Carolina, Charleston, South Carolina 29403, USA.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't