title: Protein interactions with the platelet integrin alpha(IIb) regulatory motif.
abstract: Integrins are transmembrane proteins regulating cellular shape, mobility and the cell cycle. A highly conserved signature motif in the cytoplasmic tail of the integrin alpha-subunit, KXGFFKR, plays a critical role in regulating integrin function. To date, six proteins have been identified that target this motif of the platelet-specific integrin alpha(IIb)beta(3). We employ peptide-affinity chromatography followed-up with LC-MS/MS analysis as well as protein chips to identify new potential regulators of integrin function in platelets and put them into their biological context using information from protein:protein interaction (PPI) databases. Totally, 44 platelet proteins bind with high affinity to an immobilized LAMWKVGFFKR-peptide. Of these, seven have been reported in the PPI literature as interactors with integrin alpha-subunits. 68 recombinant human proteins expressed on the protein chip specifically bind with high affinity to biotin-tagged alpha-integrin cytoplasmic peptides. Two of these proteins are also identified in the peptide-affinity experiments, one is also found in the PPI databases and a further one is present in the data to all three approaches. Finally, novel short linear interaction motifs are common to a number of proteins identified.
authors.affiliation: Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland. mraab@rcsi.ie
authors.forename: Markus
authors.initials: M
authors.lastname: Raab
authors.forename: Heide
authors.initials: H
authors.lastname: Daxecker
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Edwards
authors.forename: Achim
authors.initials: A
authors.lastname: Treumann
authors.forename: Derek
authors.initials: D
authors.lastname: Murphy
authors.forename: Niamh
authors.initials: N
authors.lastname: Moran
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001792:Blood Platelets / Q000378:metabolism*; D002846:Chromatography, Affinity / Q000379:methods; D002853:Chromatography, Liquid; D006801:Humans; D039421:Integrin alpha2 / Q000378:metabolism*; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism; D025941:Protein Interaction Mapping / Q000379:methods; D011506:Proteins / Q000378:metabolism*; D053719:Tandem Mass Spectrometry
chemical_list: C056564:ITGA2B protein, human; D039421:Integrin alpha2; D010455:Peptides; D011506:Proteins