title: Tetraspanin Tspan9 regulates platelet collagen receptor GPVI lateral diffusion and activation.
abstract: The tetraspanins are a superfamily of four-transmembrane proteins, which regulate the trafficking, lateral diffusion and clustering of the transmembrane proteins with which they interact. We have previously shown that tetraspanin Tspan9 is expressed on platelets. Here we have characterised gene-trap mice lacking Tspan9. The mice were viable with normal platelet numbers and size. Tspan9-deficient platelets were specifically defective in aggregation and secretion induced by the platelet collagen receptor GPVI, despite normal surface GPVI expression levels. A GPVI activation defect was suggested by partially impaired GPVI-induced protein tyrosine phosphorylation. In mechanistic experiments, Tspan9 and GPVI co-immunoprecipitated and co-localised, but super-resolution imaging revealed no defects in collagen-induced GPVI clustering on Tspan9-deficient platelets. However, single particle tracking using total internal reflection fluorescence microscopy showed that GPVI lateral diffusion was reduced by approximately 50% in the absence of Tspan9. Therefore, Tspan9 plays a fine-tuning role in platelet activation by regulating GPVI membrane dynamics.
authors.affiliation: a School of Biosciences, College of Life and Environmental Sciences , University of Birmingham , Birmingham , UK.
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Haining
authors.affiliation: a School of Biosciences, College of Life and Environmental Sciences , University of Birmingham , Birmingham , UK.
authors.forename: Alexandra L
authors.initials: AL
authors.lastname: Matthews
authors.affiliation: a School of Biosciences, College of Life and Environmental Sciences , University of Birmingham , Birmingham , UK.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Noy
authors.affiliation: b Department of Pathology , Medical University of Łódź , Poland.
authors.forename: Hanna M
authors.initials: HM
authors.lastname: Romanska
authors.affiliation: a School of Biosciences, College of Life and Environmental Sciences , University of Birmingham , Birmingham , UK.
authors.forename: Helen J
authors.initials: HJ
authors.lastname: Harris
authors.affiliation: a School of Biosciences, College of Life and Environmental Sciences , University of Birmingham , Birmingham , UK.|c PSIBS Doctoral Training Centre, School of Chemistry , University of Birmingham , Birmingham , UK.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Pike
authors.affiliation: d Department of Experimental Biomedicine, University Hospital , University of Würzburg, Würzburg , Germany.
authors.forename: Martina
authors.initials: M
authors.lastname: Morowski
authors.affiliation: a School of Biosciences, College of Life and Environmental Sciences , University of Birmingham , Birmingham , UK.
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Gavin
authors.affiliation: a School of Biosciences, College of Life and Environmental Sciences , University of Birmingham , Birmingham , UK.
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.affiliation: e INSERM U1054, CNRS, UMR 5048, Centre de Biochimie Structurale , Montpellier University , France.
authors.forename: Pierre-Emmanuel
authors.initials: PE
authors.lastname: Milhiet
authors.affiliation: f Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences , University of Birmingham , Birmingham , UK.
authors.forename: Fedor
authors.initials: F
authors.lastname: Berditchevski
authors.affiliation: d Department of Experimental Biomedicine, University Hospital , University of Würzburg, Würzburg , Germany.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Nieswandt
authors.affiliation: g Institute of Cardiovascular Sciences, College of Medical and Dental Sciences , University of Birmingham , Birmingham , UK.
authors.forename: Natalie S
authors.identifier: http://orcid.org/0000-0002-3187-2130
authors.initials: NS
authors.lastname: Poulter
authors.affiliation: g Institute of Cardiovascular Sciences, College of Medical and Dental Sciences , University of Birmingham , Birmingham , UK.
authors.forename: Steve P
authors.identifier: http://orcid.org/0000-0002-7846-7423
authors.initials: SP
authors.lastname: Watson
authors.affiliation: a School of Biosciences, College of Life and Environmental Sciences , University of Birmingham , Birmingham , UK.
authors.forename: Michael G
authors.identifier: http://orcid.org/0000-0002-1189-0091
authors.initials: MG
authors.lastname: Tomlinson
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000818:Animals; D016718:Arachidonic Acid / Q000494:pharmacology; D001792:Blood Platelets / Q000378:metabolism* / Q000473:pathology; D002352:Carrier Proteins / Q000494:pharmacology; D002462:Cell Membrane / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010455:Peptides / Q000494:pharmacology; D010766:Phosphorylation; D015539:Platelet Activation / Q000187:drug effects*; D010974:Platelet Aggregation / Q000187:drug effects; D010980:Platelet Membrane Glycoproteins / Q000235:genetics* / Q000378:metabolism; D061251:Primary Cell Culture; D011485:Protein Binding; D021381:Protein Transport; D015398:Signal Transduction; D059470:Tetraspanins / Q000737:chemistry / Q000172:deficiency / Q000235:genetics*
chemical_list: D002352:Carrier Proteins; D010455:Peptides; D010980:Platelet Membrane Glycoproteins; D059470:Tetraspanins; C000627766:Tspan9 protein, mouse; C435908:collagen-related peptide; C098341:platelet membrane glycoprotein VI; D016718:Arachidonic Acid; D000244:Adenosine Diphosphate
keywords: GPVI; Tspan9; platelet; single particle analysis; super-resolution imaging; tetraspanin