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Updated: May 24, 2026

Generation of Human Chimeric Antigen Receptor Regulatory T Cells
Published on: January 3, 2025
TCR-mediated Erk activation does not depend on Sos and Grb2 in peripheral human T cells
Nicole Warnecke1, Mateusz Poltorak, Bhavani S Kowtharapu
1Institute of Molecular and Clinical Immunology, Otto-von-Guericke University, Leipziger Strasse 44, Magdeburg 39120, Germany.
Abstract:
Sos proteins are ubiquitously expressed activators of Ras. Lymphoid cells also express RasGRP1, another Ras activator. Sos and RasGRP1 are thought to cooperatively control full Ras activation upon T-cell receptor triggering. Using RNA interference, we evaluated whether this mechanism operates in primary human T cells. We found that T-cell antigen receptor (TCR)-mediated Erk activation requires RasGRP1, but not Grb2/Sos. Conversely, Grb2/Sos—but not RasGRP1—are required for IL2-mediated Erk activation. Thus, RasGRP1 and Grb2/Sos are insulators of signals that lead to Ras activation induced by different stimuli, rather than cooperating downstream of the TCR.
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