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Novel alpha 2 beta 1 Integrin Inhibitors Reveal That Integrin Binding to Collagen under Shear Stress Conditions Does Not Require Receptor Preactivation
Tekijät: Nissinen L, Koivunen J, Käpylä J, Salmela M, Nieminen J, Jokinen J, Sipilä K, Pihlavisto M, Pentikäinen OT, Marjamäki A, Heino J
Kustantaja: AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
Julkaisuvuosi: 2012
Lehti:Journal of Biological Chemistry
Tietokannassa oleva lehden nimiJOURNAL OF BIOLOGICAL CHEMISTRY
Lehden akronyymi: J BIOL CHEM
Numero sarjassa: 53
Vuosikerta: 287
Numero: 53
Aloitussivu: 44694
Lopetussivu: 44702
Sivujen määrä: 9
ISSN: 0021-9258
DOI: https://doi.org/10.1074/jbc.M111.309450
Rinnakkaistallenteen osoite: https://research.utu.fi/converis/portal/detail/Publication/2678698
The interaction between alpha 2 beta 1 integrin (GPIa/IIa, VLA-2) and vascular collagen is one of the initiating events in thrombus formation. Here, we describe two structurally similar sulfonamide derivatives, BTT-3033 and BTT-3034, and show that, under static conditions, they have an almost identical effect on alpha 2-expressing CHO cell adhesion to collagen I, but only BTT-3033 blocks platelet attachment under flow (90 dynes/cm(2)). Differential scanning fluorimetry showed that both molecules bind to the alpha 2I domain of the recombinant alpha 2 subunit. To further study integrin binding mechanism(s) of the two sulfonamides, we created an alpha 2 Y285F mutant containing a substitution near the metal ion-dependent adhesion site motif in the alpha 2I domain. The action of BTT-3033, unlike that of BTT-3034, was dependent on Tyr-285. In static conditions BTT-3034, but not BTT3033, inhibited collagen binding by an alpha 2 variant carrying a conformationally activating E318W mutation. Conversely, in under flow conditions (90 dynes/cm(2)) BTT-3033, but not BTT-3034, inhibited collagen binding by an alpha 2 variant expressing E336A loss-of-function mutation. Thus, the binding sites for BTT-3033 and BTT-3034 are differentially available in distinct integrin conformations. Therefore, these sulfonamides can be used to study the biological role of different functional stages of alpha 2 beta 1. Furthermore, only the inhibitor that recognized the nonactivated conformation of alpha 2 beta 1 integrin under shear stress conditions effectively blocked platelet adhesion, suggesting that the initial interaction between integrin and collagen takes place prior to receptor activation.
Ladattava julkaisu This is an electronic reprint of the original article. |  |
