title: Proteomic identification of pleckstrin-associated proteins in platelets: possible interactions with actin.
abstract: Pleckstrin (plek)-null platelets from a knockout mouse have been shown to be defective in granule secretion, aggregation and actin polymerization. However, the mechanism of plek signaling is currently unknown. Therefore, we sought to identify plek-binding proteins in platelets by using GST pulldown assays and immunoprecipitation to isolate proteins from extracts of protein kinase C-activated or inhibited human platelets. Co-purified plek-binding proteins were resolved by SDS-PAGE and identified via nanospray quadruple TOF MS. Identified proteins may be involved in various cellular processes including cytoskeletal reorganization (moesin, radixin and alpha-actinin) and signal transduction (serum deprivation response protein, 17 beta-hydroxysteroid dehydrogenase 4 and factor XIIIA). Both platelet aggregation and/or secretion require actin polymerization. However, studies have shown no direct association between plek and actin. Based on our findings we propose indirect associations between plek and actin through 17 beta-hydroxysteroid dehydrogenase 4, alpha-actinin, moesin, radixin and factor XIIIA, which in turn suggest new roles for plek in platelet biology.
authors.affiliation: Department of Pathology, McMaster University, Hamilton, ON, Canada. akeel.baig@gmail.com
authors.forename: Akeel
authors.initials: A
authors.lastname: Baig
authors.forename: Xiankun
authors.initials: X
authors.lastname: Bao
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Haslam
mesh_terms: D000199:Actins / Q000378:metabolism*; D001792:Blood Platelets / Q000378:metabolism*; D001798:Blood Proteins / Q000378:metabolism*; D006801:Humans; D047468:Immunoprecipitation; D013058:Mass Spectrometry; D010750:Phosphoproteins / Q000378:metabolism*; D011485:Protein Binding; D040901:Proteomics; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015203:Reproducibility of Results
chemical_list: D000199:Actins; D001798:Blood Proteins; D010750:Phosphoproteins; D011993:Recombinant Fusion Proteins; C039077:platelet protein P47