Distinctive T cell-suppressive signals from nuclearized type 1 sphingosine 1-phosphate G protein-coupled receptors

Abstract

Sphingosine 1-phosphate (S1P) generated by cells of innate immunity and the type 1 S1P G protein-coupled receptor (S1P1) on mobile T cells constitute a major system for control of lymphoid organ traffic and tissue migration of T cells. Now we show that T cell activation mediated by the T cell antigen receptor translocates plasma membrane S1P1 to nuclear envelope membranes for association there with Gi/o, Erk 1/2, and other proteins that plasma membrane S1P1 uses to signal T cell proliferation. However, nuclear S1P1 and plasma membrane S1P 1 transduce opposite effects of S1P on T cell proliferation and relevant signaling as exemplified by respective decreases and increases in T cell nuclear concentrations of both phospho-Erk and active (phosphorylated) c-Jun. T cell antigen receptor-mediated activation of T cells therefore both eliminates migration responses to S1P by down-regulation of plasma membrane S1P1 and translocates the S1P-S1P1 axis into the nuclear domain where signals are directed to transcriptional control of immune functions other than migration. © 2007 by The American Society for Biochemistry and Molecular Biology, Inc.