Thrombospondin-1 acts via IAP/CD47 to synergize with collagen in alpha2beta1-mediated platelet activation.
Thrombospondin-1 acts via IAP/CD47 to synergize with collagen in alpha2beta1-mediated platelet activation.
复制标题
DOI：
--
复制
发表时间：
1999
期刊：
影响因子：
20.3
通讯作者：
J. Chung;X. Wang;F. Lindberg;W. Frazier
中科院分区：
文献类型：
--
作者：
J. Chung;X. Wang;F. Lindberg;W. Frazier
Integrin-associated protein (IAP; or CD47) is a receptor for the cell binding domain (CBD) of thrombospondin-1 (TS1). In platelets, IAP associates with and regulates the function of alphaIIbbeta3 integrin (Chung et al, J Biol Chem 272:14740, 1997). We test here the possibility that CD47 may also modulate the function of platelet integrin alpha2beta1, a collagen receptor. The CD47 agonist peptide, 4N1K (KRFYVVMWKK), derived from the CBD, synergizes with soluble collagen in aggregating platelet-rich plasma. 4N1K and intact TS1 also induce the aggregation of washed, unstirred platelets on immobilized collagen with a rapid increase in tyrosine phosphorylation. The effects of TS1 and 4N1K on platelet aggregation are absolutely dependent on IAP, as shown by the use of platelets from IAP-/- mice. Prostaglandin E1 (PGE1) prevents 4N1K-dependent aggregation on immobilized collagen but does not inhibit the 4N1K peptide stimulation of alpha2beta1-dependent platelet spreading. Finally, a detergent-stable, physical association of IAP and alpha2beta1 integrin is detected by coimmunoprecipitation. These results imply a role for IAP and TS1 in the early activation of platelets upon adhesion to collagen.
