title: Synergistic adhesive interactions and signaling mechanisms operating between platelet glycoprotein Ib/IX and integrin alpha IIbbeta 3. Studies in human platelets ans transfected Chinese hamster ovary cells.
abstract: This study investigates three aspects of the adhesive interaction operating between platelet glycoprotein Ib/IX and integrin alpha(IIb)beta(3). These include the following: 1) examining the sufficiency of GPIb/IX and integrin alpha(IIb)beta(3) to mediate irreversible cell adhesion on immobilized von Willebrand factor (vWf) under flow; 2) the ability of the vWf-GPIb interaction to induce integrin alpha(IIb)beta(3) activation independent of endogenous platelet stimuli; and 3) the identification of key second messengers linking the vWf-GPIb/IX interaction to integrin alpha(IIb)beta(3) activation. By using Chinese hamster ovary cells transfected with GPIb/IX and integrin alpha(IIb)beta(3), we demonstrate that these receptors are both necessary and sufficient to mediate irreversible cell adhesion under flow, wherein GPIb/IX mediates cell tethering and rolling on immobilized vWf, and integrin alpha(IIb)beta(3) mediates cell arrest. Moreover, we demonstrate direct signaling between GPIb/IX and integrin alpha(IIb)beta(3). Studies on human platelets demonstrated that vWf binding to GPIb/IX is able to induce integrin alpha(IIb)beta(3) activation independent of endogenous platelet stimuli under both static and physiological flow conditions (150-1800 s(-)(1)). Analysis of the key second messengers linking the vWf-GPIb interaction to integrin alpha(IIb)beta(3) activation demonstrated that the first step in the activation process involves calcium release from internal stores, whereas transmembrane calcium influx is a secondary event potentiating integrin alpha(IIb)beta(3) activation.
authors.affiliation: Australian Centre for Blood Diseases, Department of Medicine, Monash Medical School, Box Hill Hospital, Victoria 3128, Australia.
authors.forename: C L
authors.initials: CL
authors.lastname: Yap
authors.forename: S C
authors.initials: SC
authors.lastname: Hughan
authors.forename: S L
authors.initials: SL
authors.lastname: Cranmer
authors.forename: W S
authors.initials: WS
authors.lastname: Nesbitt
authors.forename: M M
authors.initials: MM
authors.lastname: Rooney
authors.forename: S
authors.initials: S
authors.lastname: Giuliano
authors.forename: S
authors.initials: S
authors.lastname: Kulkarni
authors.forename: S M
authors.initials: SM
authors.lastname: Dopheide
authors.forename: Y
authors.initials: Y
authors.lastname: Yuan
authors.forename: H H
authors.initials: HH
authors.lastname: Salem
authors.forename: S P
authors.initials: SP
authors.lastname: Jackson
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000818:Animals; D016466:CHO Cells; D002118:Calcium / Q000378:metabolism; D002448:Cell Adhesion; D006224:Cricetinae; D004533:Egtazic Acid / Q000494:pharmacology; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000502:physiology*; D019038:Platelet Glycoprotein GPIb-IX Complex / Q000502:physiology*; D011493:Protein Kinase C / Q000502:physiology; D013928:Thromboxane A2 / Q000502:physiology; D014162:Transfection; D014841:von Willebrand Factor / Q000378:metabolism
chemical_list: D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D019038:Platelet Glycoprotein GPIb-IX Complex; D014841:von Willebrand Factor; D004533:Egtazic Acid; D013928:Thromboxane A2; D000244:Adenosine Diphosphate; D011493:Protein Kinase C; D002118:Calcium