COAT platelets.
OBJECTIVE
COAT platelets are a recently described subpopulation of cells resulting from simultaneous activation with collagen and thrombin. The complete process by which COAT platelets are produced is still not clear, although significant recent progress has been made.


RESULTS
COAT platelets retain several procoagulant proteins on their surface by a previously unrecognized mechanism involving transglutaminase mediated conjugation of serotonin to released alpha-granule proteins. Fibrinogen and thrombospondin have been found to bind serotonin-conjugated proteins and thereby provide the requisite link for stabilization of serotonin-derivatized, procoagulant proteins on COAT platelets.


CONCLUSIONS
Multivalent interactions, resulting from traditional receptor interactions and binding of conjugated serotonin by fibrinogen and thrombospondin, result in exceptionally strong retention of procoagulant alpha-granule proteins on the surface of COAT platelets. The physiologic significance of this new subclass of platelets remains to be determined.
Szasz
Robert
R
Department of Medicine, BSEB 302, OU Health Sciences Center, 941 S.L. Young Boulevard, Oklahoma City, OK 73104, USA.
Dale
George L
GL
D001792:Blood Platelets / Q000502:physiology*; D003094:Collagen / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D015539:Platelet Activation; D013917:Thrombin / Q000378:metabolism
D003094:Collagen; D013917:Thrombin