title: A combined proteomic and genetic analysis of the highly variable platelet proteome: from plasmatic proteins and SNPs.
abstract: High biological variation in protein expression represents a major challenge in clinical proteomics. In a study based on 2D-DIGE, we found that the standardised abundance of only a few proteins varied by more than 50%. While some of the highest variable proteins in platelets of 52 healthy elderly were of plasmatic origin, such as albumin or haptoglobin, absence of several other high-abundant plasma proteins strongly suggests that plasma-derived proteins represent an integral part of the platelet proteome. Amongst the highly variable platelet-derived proteins, two spots were both identified as GSTO1 and assigned to either the wild-type or mutant isoform of SNP A140D. Remarkably, when the spots were considered within the respective genotype groups, their CV decreased to about the median variation. Albeit 2D-DIGE allowed correct genotyping, two individuals seemed to be GSTO1*A140 deficient. Probing 2D-Western blots with novel mAb, however, detected A140 protein as additional spot at pH 8.1, caused by the SNPs E155del and E208K. In contrast to previous studies, we show that GSTO1 protein is expressed in vivo, despite the deletion E155. Our data indicate that incorporation of exogenous proteins and genetic polymorphisms of endogenous proteins represent the main source of extreme biological variation in the platelet proteome.
authors.affiliation: Institute of Physiology, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Veitinger
authors.forename: Ellen
authors.initials: E
authors.lastname: Umlauf
authors.forename: Roland
authors.initials: R
authors.lastname: Baumgartner
authors.forename: Sigrun
authors.initials: S
authors.lastname: Badrnya
authors.forename: Jonny
authors.initials: J
authors.lastname: Porter
authors.forename: John
authors.initials: J
authors.lastname: Lamont
authors.forename: Christopher
authors.initials: C
authors.lastname: Gerner
authors.forename: Christian W
authors.initials: CW
authors.lastname: Gruber
authors.forename: Rudolf
authors.initials: R
authors.lastname: Oehler
authors.forename: Maria
authors.initials: M
authors.lastname: Zellner
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001792:Blood Platelets / Q000737:chemistry*; D001798:Blood Proteins / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D005982:Glutathione Transferase / Q000097:blood / Q000235:genetics*; D006801:Humans; D008297:Male; D020641:Polymorphism, Single Nucleotide; D020543:Proteome / Q000032:analysis*; D040901:Proteomics; D057825:Two-Dimensional Difference Gel Electrophoresis
chemical_list: D001798:Blood Proteins; D020543:Proteome; C490476:GSTO1 protein, human; D005982:Glutathione Transferase