The peptide LSARLAF causes platelet secretion and aggregation by directly activating the integrin alphaIIbbeta3.
A novel peptide (designed to bind to alphaIIbbeta3) caused platelet aggregation and aggregation-independent secretion of the contents of alpha-granules in an alphaIIbbeta3-dependent fashion. The agonist peptide induced secretion in the presence of prostaglandin E1. In cell-free assays, alphaIIbbeta3 bound specifically to immobilized agonist peptide and the peptide enhanced the binding of fibrinogen to immobilized alphaIIbbeta3. The agonist peptide apparently activates alphaIIbbeta3 by directly inducing a conformational change in the receptor. This change activates the platelets and causes secretion in a manner independent of fibrinogen binding.
Derrick
J M
JM
Microbiology and Molecular Cell Sciences, University of Memphis, Campus Box 526041, Memphis, TN 38152, USA.
Taylor
D B
DB
Loudon
R G
RG
Gartner
T K
TK
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism*; D018076:DNA, Complementary / Q000737:chemistry; D005340:Fibrinogen / Q000378:metabolism; D009842:Oligopeptides / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D010974:Platelet Aggregation / Q000187:drug effects*; D010978:Platelet Factor 4 / Q000378:metabolism; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D012333:RNA, Messenger / Q000737:chemistry
D000911:Antibodies, Monoclonal; D018076:DNA, Complementary; D009842:Oligopeptides; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D012333:RNA, Messenger; D010978:Platelet Factor 4; D005340:Fibrinogen