Proteomic analysis of platelet alpha-granules using mass spectrometry.

Abstract

BACKGROUND:

Platelets have three major types of secretory organelles: lysosomes, dense granules, and alpha-granules. alpha-Granules contain several adhesive proteins involved in hemostasis, as well as glycoproteins involved in inflammation, wound healing, and cell-matrix interactions. This article represents the first effort to define the platelet alpha-granule proteome using mass spectrometry (MS).

METHODS:

We prepared a subcellular fraction enriched in intact alpha-granules from human platelets using sucrose gradient ultracentrifugation. alpha-Granule proteins were separated and identified using sodium dodecylsulfate polyacrylamide gel electrophoresis and liquid chromatography-tandem MS.

RESULTS:

In the sucrose fraction enriched in alpha-granules, we identified 284 non-redundant proteins, 44 of which appear to be new alpha-granule proteins, on the basis of a literature review. Immunoelectron microscopy confirmed the presence of Scamp2, APLP2, ESAM and LAMA5 in platelet alpha-granules for the first time. We identified 65% of the same proteins that were detected in the platelet releasate (J. A. Coppinger et al. [Blood 2004;103: 2096-104]) as well as additional soluble and membrane proteins. Our method provides a suitable tool for analyzing the granule proteome of patients with storage pool deficiencies.

• Authors: D M Maynard, H F G Heijnen, M K Horne, J G White, W A Gahl
• Journal: Journal of thrombosis and haemostasis : JTH (J Thromb Haemost) Vol. 5 Issue 9 Pg. 1945-55 (Sep 2007) ISSN: 1538-7933 [Print] England
• PMID: 17723134 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)

Topics

• Blood Platelets (ultrastructure)
• Blotting, Western
• Electrophoresis, Polyacrylamide Gel
• Humans
• Mass Spectrometry
• Microscopy, Electron, Transmission
• Organelles (metabolism, ultrastructure)
• Proteomics