Model depicting the pathways linking activated Notch3 with the induction of cyclin D1. Notch3-IC has been shown to activate the pTα promoter, thus promoting activation of pre-TCR signaling that in turn results in ERK1/2 activation. Signaling through the IL-2/IL-2R pathway acts to increases Tal1 expression. The induction of pTal1/Sp1 complex through a pre-TCR/ERK1/2-dependent pathway activates cyclin D1 expression.