© The Rockefeller University Press, 0022-1007/2000/3/985/ $5.00
The Journal of Experimental Medicine, Volume 191, Number 6, March 20, 2000 985-994
Cytokine-induced Src Homology 2 Protein (CIS) Promotes T Cell Receptormediated Proliferation and Prolongs Survival of Activated T Cells
Suling Lia,
Shangwu Chena,
Xiufeng Xub,
Anette Sundstedta,
Kajsa M. Paulssona,
Per Andersona,
Stefan Karlssonb,
Hans-Olov Sjögrena, and
Ping Wanga
a Department of Tumor Immunology, Lund University, S-22362 Lund, Sweden
b Department of Molecular Medicine and Gene Therapy, Lund University, S-22362 Lund, Sweden
Correspondence to:
Suling Li, Tumor Immunology, Lund University, Slovegatan 21, S-22362 Lund, Sweden. Tel:46-46-2227848 Fax:46-46-2224606 E-mail:ping.wang{at}wblab.lu.se or su-ling.li@wblab.lu.se.
Released online: 20 March 2000
Members of the suppressor of cytokine signaling (SOCS) family were discovered as negative regulators of cytokine signaling by inhibition of the Janus kinasesignal transducer and activator of transcription (Jak-STAT) pathway. Among them, cytokine-induced Src homology 2 (SH2) protein (CIS) was found to inhibit the interleukin 3 and erythropietin-mediated STAT5 signaling pathway. However, involvement of SOCS proteins in other signaling pathways is still unknown. This study shows that the expression of CIS is selectively induced in T cells after T cell receptor (TCR) stimulation. In transgenic mice, with selective expression of CIS in CD4 T cells, elevated CIS strongly promotes TCR-mediated proliferation and cytokine production in vitro, and superantigen-induced T cell activation in vivo. Forced expression of CIS also prolongs survival of CD4 T cells after TCR activation. Molecular events immediately downstream from the TCR are not changed in CIS-expressing CD4 T cells, but activation of mitogen-activated protein (MAP) kinase pathways by TCR stimulation is significantly enhanced. Together with the increased MAP kinase activation, a direct interaction of CIS and protein kinase C
was also demonstrated. These results suggest that CIS is one of the important regulators of TCR-mediated T cell activation. The functions of CIS, enhancing TCR signaling and inhibiting cytokine signaling, may be important in the regulation of immune response and homeostasis.
Key Words:
cytokine-induced SH2 protein, T cell receptor, signal transduction, mitogen-activated protein kinases, T cell activation