Anja E. Eisenhardt

Anja Meyer

Gina J. Fiala

Kong

Lisa C. Schmitt

Mercer

Mogjiborahman Salek

Oreste Acuto

Secrist

Storm

Sumit Deswal

Tilman Brummer

Weber

Whitehurst

Wolfgang W. A. Schamel

Abstract
               The activation kinetics of MAPK Erk are critical for T cell development and activation. In particular, sustained Erk signaling is required for T cell activation and effector functions, such as IL-2 production. Although Raf-1 triggers transient Erk activation, B-Raf is implicated in sustained Erk signaling after TCR stimulation. In this study, we show that B-Raf is dephosphorylated on its inhibitory serine 365 upon TCR triggering. However, it is unknown how B-Raf activation is coupled to the TCR. Using mass spectrometry, we identified protein kinase D–interacting substrate of 220 kDa (Kidins220)/ankyrin repeat-rich membrane spanning protein, mammalian target of rapamycin, Rictor, Dock2, and GM130 as novel B-Raf interaction partners. We focused on Kidins220, a protein that has been studied in neuronal cells and found that it associated with the pre-TCR, αβTCR, and γδTCR. Upon prolonged TCR stimulation, the Kidins220–TCR interaction was reduced, as demonstrated by immunoprecipitation and proximity ligation assays. We show that Kidins220 is required for TCR-induced sustained, but not transient, Erk activation. Consequently, induction of the immediate early gene products and transcription factors c-Fos and Erg-1 was blocked, and upregulation of the activation markers CD69, IL-2, and IFN-γ was reduced. Further, Kidins220 was required for optimal calcium signaling. In conclusion, we describe Kidins220 as a novel TCR-interacting protein that couples B-Raf to the TCR. Kidins220 is mandatory for sustained Erk signaling; thus, it is crucial for TCR-mediated T cell activation.</jats:p

Crossref

The Journal of Immunology

Kidins220/ARMS Associates with B-Raf and the TCR, Promoting Sustained Erk Signaling in T Cells

Kidins220/ARMS Associates with B-Raf and the TCR, Promoting Sustained Erk Signaling in T Cells

Abstract

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