title: C-type lectin like receptor 2 (CLEC-2) signals independently of lipid raft microdomains in platelets.
abstract: C-type lectin like receptor 2 (CLEC-2) has been reported to activate platelets through a lipid raft-dependent manner. Secreted ADP potentiates CLEC-2-mediated platelet aggregation. We have investigated whether the decrease in CLEC-2-mediated platelet aggregation, previously reported in platelets with disrupted rafts, is a result of the loss of agonist potentiation by ADP. We disrupted platelet lipid rafts with methyl-β-cyclodextrin (MβCD) and measured signaling events downstream of CLEC-2 activation. Lipid raft disruption decreases platelet aggregation induced by CLEC-2 agonists. The inhibition of platelet aggregation by the disruption of lipid rafts was rescued by the exogenous addition of epinephrine but not 2-methylthioadenosine diphosphate (2MeSADP), which suggests that lipid raft disruption effects P2Y12-mediated Gi activation but not Gz. Phosphorylation of Syk (Y525/526) and PLCγ2 (Y759), were not affected by raft disruption in CLEC-2 agonist-stimulated platelets. Furthermore, tyrosine phosphorylation of the CLEC-2 hemi-ITAM was not effected when MβCD disrupts lipid rafts. Lipid rafts do not directly contribute to CLEC-2 receptor activation in platelets. The effects of disruption of lipid rafts in in vitro assays can be attributed to inhibition of ADP feedback that potentiates CLEC-2 signaling.
authors.affiliation: Department of Physiology, Temple University School of Medicine, Philadelphia, PA, USA; Sol Sherry Thrombosis Research Center and Temple University School of Medicine, Philadelphia, PA, USA.
authors.forename: Bhanu Kanth
authors.initials: BK
authors.lastname: Manne
authors.affiliation: Department of Physiology, Temple University School of Medicine, Philadelphia, PA, USA; Sol Sherry Thrombosis Research Center and Temple University School of Medicine, Philadelphia, PA, USA.
authors.forename: Rachit
authors.initials: R
authors.lastname: Badolia
authors.affiliation: Department of Physiology, Temple University School of Medicine, Philadelphia, PA, USA; Sol Sherry Thrombosis Research Center and Temple University School of Medicine, Philadelphia, PA, USA.
authors.forename: Carol A
authors.initials: CA
authors.lastname: Dangelmaier
authors.affiliation: Department of Physiology, Temple University School of Medicine, Philadelphia, PA, USA; Sol Sherry Thrombosis Research Center and Temple University School of Medicine, Philadelphia, PA, USA. Electronic address: spk@temple.edu.
authors.forename: Satya P
authors.initials: SP
authors.lastname: Kunapuli
mesh_terms: D001792:Blood Platelets / Q000378:metabolism*; D006801:Humans; D037181:Lectins, C-Type / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000378:metabolism*; D021962:Membrane Microdomains / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*
chemical_list: C104778:CLEC2B protein, human; D037181:Lectins, C-Type; D008562:Membrane Glycoproteins
keywords: Lipid rafts; P2Y12; Platelet activation; Platelets; Signal transduction