title: Differential binding of ICln in platelets to integrin-derived activating and inhibitory peptides.
abstract: The capacity of platelets to form a thrombus is mediated by integrin alpha(IIb)beta(3). The cytoplasmic tail of alpha(IIb) contains a highly conserved motif, (989)KVGFFKR(995), which plays a critical role in regulating integrin activation and acts as a recognition site for various intracellular proteins, e.g. CIB1, PP1, ICln and RN181. Previously, we demonstrated that a cell-permeable integrin-derived activating (IDA) peptide, KVGFFKR, induces platelet activation, whereas an integrin-derived inhibitory (IDI) peptide, KVGAAKR, is antithrombotic. To elucidate the molecular mechanism underlying these opposite effects we investigate the affinity of known integrin alpha(IIb) binding proteins for the two immobilized peptides in dependence on the activation state of platelets by means of peptide-affinity chromatography, blotting techniques and protein:peptide docking studies. Our results provide a model for the inhibition of ICln interaction with the integrin in activated platelets by the IDI-peptide. Thus, ICln:IDI-peptide interaction profiles can have a pivotal purpose in the search for consensus pharmacophores specifically inhibiting ICln function in platelets potentially leading to the development of integrin-derived antithrombotic drugs.
authors.affiliation: Royal College of Surgeons, Dublin, Ireland.
authors.forename: Markus
authors.initials: M
authors.lastname: Raab
authors.forename: Laavanya
authors.initials: L
authors.lastname: Parthasarathi
authors.forename: Achim
authors.initials: A
authors.lastname: Treumann
authors.forename: Niamh
authors.initials: N
authors.lastname: Moran
authors.forename: Heide
authors.initials: H
authors.lastname: Daxecker
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001792:Blood Platelets / Q000378:metabolism*; D006801:Humans; D007473:Ion Channels / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism; D013927:Thrombosis / Q000378:metabolism*
chemical_list: C410035:CLNS1A protein, human; D007473:Ion Channels; D009842:Oligopeptides; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D011994:Recombinant Proteins