The Journal of Experimental Medicine
VeriKine-HS Human IFN-Beta
  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents
This Article
Right arrow Full Text
Right arrow Full Text (PDF, 371K)
Right arrow PPT slides of all figures
Right arrow Alert me when this article is cited
Right arrow Citation Map
Services
Right arrow Email this article
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new content in the JEM
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Ezumi, Y.
Right arrow Articles by Takayama, H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ezumi, Y.
Right arrow Articles by Takayama, H.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Facebook   Add to Reddit   Add to Technorati   Add to Twitter  
What's this?
© The Rockefeller University Press, 0022-1007/1998/7/267/ $5.00
The Journal of Experimental Medicine, Volume 188, Number 2, July 20, 1998 267-276

Articles

Physical and Functional Association of the Src Family Kinases Fyn and Lyn with the Collagen Receptor Glycoprotein VI-Fc Receptor {gamma} Chain Complex on Human Platelets

Yasuharu Ezumi, Keisuke Shindoh, Masaaki Tsuji, and Hiroshi Takayama

From the Department of Hematology and Oncology, Clinical Sciences for Pathological Organs, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan

We have previously shown that uncharacterized glycoprotein VI (GPVI), which is constitutively associated and coexpressed with Fc receptor {gamma} chain (FcR{gamma}) in human platelets, is essential for collagen-stimulated tyrosine phosphorylation of FcR{gamma}, Syk, and phospholipase C{gamma}2 (PLC{gamma}2), leading to platelet activation. Here we investigated involvement of the Src family in the proximal signals through the GPVI–FcR{gamma} complex, using the snake venom convulxin from Crotalus durissus terrificus, which specifically recognizes GPVI and activates platelets through cross-linking GPVI. Convulxin-coupled beads precipitated the GPVI–FcR{gamma} complex from platelet lysates. Collagen and convulxin induced tyrosine phosphorylation of FcR{gamma}, Syk, and PLC{gamma}2 and recruited tyrosine-phosphorylated Syk to the GPVI–FcR{gamma} complex. Using coprecipitation methods with convulxin-coupled beads and antibodies against FcR{gamma} and the Src family, we showed that Fyn and Lyn, but not Yes, Src, Fgr, Hck, and Lck, were physically associated with the GPVI–FcR{gamma} complex irrespective of stimulation. Furthermore, Fyn was rapidly activated by collagen or cross-linking GPVI. The Src family–specific inhibitor PP1 dose-dependently inhibited collagen- or convulxin-induced tyrosine phosphorylation of proteins including FcR{gamma}, Syk, and PLC{gamma}2, accompanied by a loss of aggregation and ATP release reaction. These results indicate that the Src family plays a critical role in platelet activation via the collagen receptor GPVI–FcR{gamma} complex.

Key Words: glycoprotein VI • Fc receptor {gamma} chain • Src family • collagen • platelets

Address correspondence to Hiroshi Takayama, The Department of Hematology and Oncology, Clinical Sciences for Pathological Organs, Graduate School of Medicine, Kyoto University, 54 Shogoin-Kawaracho, Sakyo-ku, Kyoto 606-8507, Japan. Phone: 81-75-751-3151; Fax: 81-75-751-3201; E-mail: hiro{at}kuhp.kyoto-u.ac.jp

Abbreviations used: anti-GPVI F(ab')2, the F(ab')2 of anti-GPVI IgG; FcR{gamma}, Fc receptor {gamma} chain; Fc{gamma}RII, low affinity Fc receptor for IgG; Fc{varepsilon}RI, high affinity Fc receptor for IgE; GP, glycoprotein; GPVI, glycoprotein VI; ITAM, immunoreceptor tyrosine-based activation motif; PLC{gamma}2, phospholipase C{gamma}2; PP1, 4-amino-5-(4-methylphenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine; RGDS, Arg-Gly-Asp-Ser; RIPA, radioimmunoprecipitation assay.


Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Facebook Facebook   Add to Reddit Reddit   Add to Technorati Technorati   Add to Twitter Twitter    What's this?


This article has been cited by other articles:



  Home | Help | Feedback | Subscriptions | Archive | Search
TABLE OF CONTENTS