The Platelet Microparticle Proteome

Platelet-derived microparticles are the most abundant type of microparticle in human blood and
contribute to many biologically significant processes. Here, we report the first proteomic analysis of
microparticles generated from activated platelets. Using 1D SDS-PAGE and liquid chromatography
coupled to a linear ion trap mass spectrometer, the identification of 578 proteins was accomplished
using a minimum of 5 MS/MS detections of at least two different peptides for each protein. These
microparticles displayed many proteins intrinsic to and well-characterized on platelets. For example,
microparticles in these experiments were found to contain membrane surface proteins including GPIIIa,
GPIIb, and P-selectin, as well other platelet proteins such as the chemokines CXCL4, CXCL7, and CCL5.
In addition, approximately 380 of the proteins identified were not found in two previous studies of the
platelet proteome. Since several of the proteins detected here have been previously implicated in
microparticle formation and/or pathological function, it is hoped that this study will help fuel future
work concerning the possible role of microparticles in various disease states.
Keywords: microparticle • platelet • proteome • mass spectrometry