title: Altered microtubule equilibrium and impaired thrombus stability in mice lacking RanBP10.
abstract: The crucial function of blood platelets in hemostasis is to prevent blood loss by stable thrombus formation. This process is driven by orchestrated mechanisms including several signal transduction cascades and morphologic transformations. The cytoplasmic microtubule modulator RanBP10 is a Ran and β1-tubulin binding protein that is essential for platelet granule release and mice lacking RanBP10 harbor a severe bleeding phenotype. In this study, we demonstrate that RanBP10-nullizygous platelets show normal adhesion on collagen and von Willebrand factor under flow conditions. However, using a ferric chloride-induced arterial thrombosis model, the formation of stable thrombi was significantly impaired, preventing vessel occlusion or leading to recanalization and thromboembolization. Delta-granule secretion was normal in mutant mice, whereas platelet shape change in aggregometry was attenuated. Lack of RanBP10 leads to increased β1-tubulin protein, which drives α-monomers into polymerized microtubules. In mutant platelets agonists failed to contract the peripheral marginal band or centralize granules. Pretreatment of wild-type platelets with taxol caused microtubule stabilization and phenocopied the attenuated shape change in response to collagen, suggesting that RanBP10 inhibits premature microtubule polymerization of β1-tubulin and plays a pivotal role in thrombus stabilization.
authors.affiliation: Department of Biochemistry, Berlin, Germany.
authors.forename: Imke
authors.initials: I
authors.lastname: Meyer
authors.forename: Stefan
authors.initials: S
authors.lastname: Kunert
authors.forename: Silke
authors.initials: S
authors.lastname: Schwiebert
authors.forename: Ina
authors.initials: I
authors.lastname: Hagedorn
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Italiano
authors.forename: Sebastian
authors.initials: S
authors.lastname: Dütting
authors.forename: Bernhard
authors.initials: B
authors.lastname: Nieswandt
authors.forename: Sebastian
authors.initials: S
authors.lastname: Bachmann
authors.forename: Harald
authors.initials: H
authors.lastname: Schulze
mesh_terms: D000818:Animals; D001158:Arteries / Q000378:metabolism / Q000473:pathology; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D002712:Chlorides; D003094:Collagen / Q000378:metabolism; D003594:Cytoplasmic Granules; D005290:Ferric Compounds; D015870:Gene Expression / Q000187:drug effects; D020662:Guanine Nucleotide Exchange Factors / Q000172:deficiency / Q000235:genetics*; D018056:Hemorheology; D051379:Mice; D018345:Mice, Knockout; D008869:Microtubule-Associated Proteins / Q000172:deficiency / Q000235:genetics*; D008870:Microtubules / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D017239:Paclitaxel / Q000494:pharmacology; D015539:Platelet Activation / Q000187:drug effects; D010973:Platelet Adhesiveness / Q000187:drug effects; D010974:Platelet Aggregation / Q000187:drug effects; D058105:Polymerization; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013927:Thrombosis / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism*; D014404:Tubulin / Q000235:genetics / Q000378:metabolism*; D014841:von Willebrand Factor / Q000378:metabolism
chemical_list: D002712:Chlorides; D005290:Ferric Compounds; D020662:Guanine Nucleotide Exchange Factors; D008869:Microtubule-Associated Proteins; D020033:Protein Isoforms; C546963:RanBP10 protein, mouse; D014404:Tubulin; D014841:von Willebrand Factor; D003094:Collagen; D017239:Paclitaxel; C024555:ferric chloride