E-NTPase/E-NTPDase: a potential regulatory role in E-kinase/PKA-mediated CD36 activation


  • Subburaj Kannan

    Corresponding author
    1. Department of Medicine, Division of Gastroenterology, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6145, USA
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Present address: Department of Microbiology and Immunology, School of Medicine, University of Texas Medical Branch, P.O. Box 25056, Galveston, TX 77555, USA. Tel./fax: +1-409-750-9060 sukannan@utmb.edu


CD36 is a platelet surface receptor protein that plays a major role in platelet aggregation and accumulation that is mediated by parasitic attachment. The CD36 receptor is constitutively phosphorylated by E-kinase/PKA, resulting in increased affinity for collagen, but preventing spontaneous platelet aggregation. Dephosphorylation of CD36 by protein phosphatase 2A (PP2A) leads to increased affinity for thrombospondin at a different rate than that of collagen-mediated platelet aggregation. Depletion of the E-kinase/PKA substrate [ATP]0by E-NTPase-mediated hydrolysis, in conjunction with inhibition of PP2A by okadaic acid, could prove to be a valuable tool in inhibiting CD36 activation, thus preventing platelet aggregation and thrombus formation.