title: Organellar proteomics of human platelet dense granules reveals that 14-3-3zeta is a granule protein related to atherosclerosis.
abstract: Dense granules, a type of platelet secretory organelle, are known to accumulate high concentrations of small molecules such as calcium, adenine nucleotides, serotonin, pyrophosphate, and polyphosphate. Protein composition of these granules has been obscure, however. In this paper, we use proteomics techniques to describe, for the first time, the soluble protein composition of platelet dense granules. We have isolated highly enriched human platelet dense granule fractions that have been analyzed using two proteomics methods. Using this approach, we have identified 40 proteins, and most of them, such as actin-associated proteins, glycolytic enzymes, and regulatory proteins, have not previously been related to the organelle. We have focused our efforts on studying 14-3-3zeta, a member of a conserved family of proteins that interact with hundreds of different proteins. We have demonstrated that 14-3-3zeta is localized mostly on dense granules and that it is secreted after platelet activation. As some proteins secreted from activated platelets could promote the development of atherosclerosis and thrombosis, we have studied the expression of 14-3-3zeta in sections of human abdominal aorta of patients with aneurysm, identifying it at the atherosclerotic plaques. Together, our results reveal new details of the composition of the platelet dense granule and suggest an extracellular function for 14-3-3zeta associated with atherosclerosis.
authors.affiliation: Unidad de Investigacion, Hospital Universitario Puerta del Mar, Facultad de Medicina, Universidad de Cadiz, Cadiz, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Hernandez-Ruiz
authors.forename: Federico
authors.initials: F
authors.lastname: Valverde
authors.forename: Maria D
authors.initials: MD
authors.lastname: Jimenez-Nuñez
authors.forename: Esther
authors.initials: E
authors.lastname: Ocaña
authors.forename: Ana
authors.initials: A
authors.lastname: Sáez-Benito
authors.forename: Javier
authors.initials: J
authors.lastname: Rodríguez-Martorell
authors.forename: Juan-Carlos
authors.initials: JC
authors.lastname: Bohórquez
authors.forename: Aurelio
authors.initials: A
authors.lastname: Serrano
authors.forename: Felix A
authors.initials: FA
authors.lastname: Ruiz
mesh_terms: D048948:14-3-3 Proteins / Q000096:biosynthesis* / Q000502:physiology*; D017544:Aortic Aneurysm, Abdominal / Q000378:metabolism; D050197:Atherosclerosis / Q000378:metabolism*; D001792:Blood Platelets / Q000378:metabolism*; D002853:Chromatography, Liquid / Q000379:methods; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D006019:Glycolysis; D006801:Humans; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D015539:Platelet Activation; D040901:Proteomics / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013347:Subcellular Fractions
chemical_list: D048948:14-3-3 Proteins