RhoH is indispensable for correct TCR activation. Illustration of the proposed mechanism that links RhoH to the active TCR complex. The ITAM-like motif of RhoH (see figure 1) allows binding of the Zap70 molecule and shuttling to the TCR CD3ζ chain. Zap70 binding to the CD3ζ chain eventually results in the activation of the linker for activation of T-cells (LAT) molecule and the so-called LAT signalosome. In the absence of RhoH, translocation of Zap70 to the immunological synapse and CD3ζ phosphorylation are impaired leading to reduced TCR-induced signalling and impaired thymocyte selection.