title: Proteomic analysis of palmitoylated platelet proteins.
abstract: Protein palmitoylation is a dynamic process that regulates membrane targeting of proteins and protein-protein interactions. We have previously demonstrated a critical role for protein palmitoylation in platelet activation and have identified palmitoylation machinery in platelets. Using a novel proteomic approach, Palmitoyl Protein Identification and Site Characterization, we have begun to characterize the human platelet palmitoylome. Palmitoylated proteins were enriched from membranes isolated from resting platelets using acyl-biotinyl exchange chemistry, followed by identification using liquid chromatography-tandem mass spectrometry. This global analysis identified > 1300 proteins, of which 215 met criteria for significance and represent the platelet palmitoylome. This collection includes 51 known palmitoylated proteins, 61 putative palmitoylated proteins identified in other palmitoylation-specific proteomic studies, and 103 new putative palmitoylated proteins. Of these candidates, we chose to validate the palmitoylation of triggering receptors expressed on myeloid cell (TREM)-like transcript-1 (TLT-1) as its expression is restricted to platelets and megakaryocytes. We determined that TLT-1 is a palmitoylated protein using metabolic labeling with [³H]palmitate and identified the site of TLT-1 palmitoylation as cysteine 196. The discovery of new platelet palmitoyl protein candidates will provide a resource for subsequent investigations to validate the palmitoylation of these proteins and to determine the role palmitoylation plays in their function.
authors.affiliation: Division of Hemostasis and Thrombosis, Beth Israel Deaconess Medical Center, Boston, MA, USA.
authors.forename: Louisa
authors.initials: L
authors.lastname: Dowal
authors.forename: Wei
authors.initials: W
authors.lastname: Yang
authors.forename: Michael R
authors.initials: MR
authors.lastname: Freeman
authors.forename: Hanno
authors.initials: H
authors.lastname: Steen
authors.forename: Robert
authors.initials: R
authors.lastname: Flaumenhaft
mesh_terms: D001774:Blood Chemical Analysis; D001792:Blood Platelets / Q000737:chemistry / Q000378:metabolism*; D001798:Blood Proteins / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D054878:Lipoylation / Q000502:physiology; D011499:Protein Processing, Post-Translational; D020543:Proteome / Q000032:analysis* / Q000378:metabolism; D040901:Proteomics / Q000379:methods
chemical_list: D001798:Blood Proteins; D020543:Proteome