Model of FasL reverse signaling and the underlying molecular mechanism. At least 2 signaling pathways might be involved in transmitting the antiproliferative stimulus into the FasL-bearing cell. Recruitment of the tyrosine phosphatase PTP-PEST by the FasL-binding adaptor protein PSTPIP may lead to inhibition of ERK1/2 activity. In parallel, triggering of FasL followed by proteolytic cleavage of the molecule by ADAM10 and SPPL2a results in liberation of the FasL ICD into the cytoplasm, from where it translocates to the nucleus and influences gene transcription by binding to and inhibiting the transcription factor Lef-1.