title: Roles of integrin β3 cytoplasmic tail in bidirectional signal transduction in a trans-dominant inhibition model.
abstract: We evaluated the roles of calpain cleavage-related mutations of the integrin β3 cytoplasmic tail in integrin αIIbβ3 bidirectional signaling using a trans-dominant inhibition model. Chimeric Tac-β3 proteins (i.e., Tac-β3, Tac-β3Δ741, Tac-β3Δ747, Tac-β3Δ754, Tac-β3Δ759, and Tac-β3ΔNITY) consisting of the extracellular and transmembrane domains of human IL-2 receptor (Tac) and the human integrin β3 cytoplasmic domain were stably expressed in the 123 CHO cells harboring human glycoprotein Ib-IX and wild-type integrin αIIbβ3. The different cells were assayed for stable adhesion and spreading on immobilized fibrinogen, and for binding soluble fibrinogen representing outside-in and inside-out signaling events, respectively. The chimeric protein Tac-β3 inhibited, and Tac-β3ΔNITY partially attenuated stable adhesion and spreading. Tac-β3, Tac-β3Δ759, Tac-β3ΔNITY, and Tac-β3Δ754, but not Tac-β3Δ747 or Tac-β3Δ741, impaired the soluble fibrinogen binding. Results indicated that the bidirectional signaling was significantly inhibited by Tac-β3 and Tac-β3ΔNITY, albeit to a much lesser extent. Moreover, only inside-out signaling was impaired in the 123/Tac-β3Δ759 and 123/Tac-β3Δ754 cells in contrast to an intact bidirectional signaling in the 123/Tac-β3Δ747 and 123/Tac-β3Δ741 cells. In conclusion, the calpain cleavage of integrin β3 resulted in the regulatory effects on signaling by interrupting its interaction with cytoplasmic proteins rather than altering its conformation, and may thus regulate platelet function.
authors.affiliation: State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.|Institute of Hematology, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310003, China.
authors.forename: Jiansong
authors.initials: J
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.|Department of Hematology, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, China.
authors.forename: Yulan
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Su
authors.affiliation: State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
authors.forename: Yuanjing
authors.initials: Y
authors.lastname: Lyu
authors.affiliation: State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
authors.forename: Lanlan
authors.initials: L
authors.lastname: Tao
authors.affiliation: State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.|Department of Hematology, Affiliated Hospital of Jiangsu University, Zhenjiang, 212001, China.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Shi
authors.affiliation: State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.|Department of Pediatrics, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200001, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.|Department of Hematology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100073, China.
authors.forename: Zhangbiao
authors.initials: Z
authors.lastname: Long
authors.affiliation: State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Ruan
authors.affiliation: State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Xiao
authors.affiliation: Shanghai Institute of Hypertension, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
authors.forename: Wenda
authors.initials: W
authors.lastname: Xi
authors.affiliation: Cyrus Tang Hematology Center, Jiangsu Institute of Hematology, 2011 Collaborative Innovation Center of Hematology, Soochow University, Suzhou, 215123, China.
authors.forename: Quansheng
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China. maojianhua110@163.com.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Mao
authors.affiliation: State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China. xixiaodong@shsmu.edu.cn.|Sino-French Research Centre for Life Sciences and Genomics, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China. xixiaodong@shsmu.edu.cn.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Xi
mesh_terms: D000818:Animals; D016466:CHO Cells; D002154:Calpain / Q000378:metabolism; D002448:Cell Adhesion; D006224:Cricetinae; D003412:Cricetulus; D005340:Fibrinogen / Q000378:metabolism*; D006801:Humans; D039661:Integrin beta3 / Q000378:metabolism*; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D039661:Integrin beta3; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D005340:Fibrinogen; D002154:Calpain
keywords: integrin β3; signal transduction; trans-dominant inhibition model