Skip to main content
. Author manuscript; available in PMC: 2010 Oct 1.
Published in final edited form as: Curr Opin Immunol. 2009 Sep 11;21(5):557–562. doi: 10.1016/j.coi.2009.08.002

Figure 2.

Figure 2

Ligation of HLA class I molecules by anti-HLA antibodies activates signaling cascades that result in EC survival and proliferation. Class I mediated EC survival and proliferation involves the activation of two distinct signaling pathways depending upon the antibody concentration. Ligation of class I molecules with high titer antibodies stimulates intracellular signals that synergize with FGF receptors to stimulate cell proliferation via the MAPK signaling pathway. Ligation of class I molecules with low titer antibodies stimulates cell survival and cell proliferation through phosphorylation of Src, FAK and paxillin followed by downstream activation of mTORC1 and mTORC2. Class I ligation leads to the activation of several downstream targets of mTORC1 signaling including S6K at Thr389, S6RP at Ser235/236, and 4E-BP1 at Thr37/46 and increases cell proliferation. Class I mediated activation of mTORC2 promotes cell survival by activating Akt at Ser473 and upregulating Bcl-2 and Bcl-xL expression.