Endosomal Phosphatidylinositol 3-Kinase Is Essential for Canonical GPCR Signaling.
G protein-coupled receptors (GPCRs), the largest family of signaling receptors, are critically regulated by endosomal trafficking, suggesting that endosomes might provide new strategies for manipulating GPCR signaling. Here we test this hypothesis by focusing on class III phosphatidylinositol 3-kinase (Vps34), which is an essential regulator of endosomal trafficking. We verify that Vps34 is required for recycling of the β2-adrenoceptor (β2AR), a prototypical GPCR, and then investigate the effects of Vps34 inhibition on the canonical cAMP response elicited by β2AR activation. Vps34 inhibition impairs the ability of cells to recover this response after prolonged activation, which is in accord with the established role of recycling in GPCR resensitization. In addition, Vps34 inhibition also attenuates the short-term cAMP response, and its effect begins several minutes after initial agonist application. These results establish Vps34 as an essential determinant of both short-term and long-term canonical GPCR signaling, and support the potential utility of the endosomal system as a druggable target for signaling.
Department of Psychiatry (Y.U., D.J., and M.Z.), Department of Cellular and Molecular Pharmacology (F.U.R., K.M.S., and M.Z.), and Howard Hughes Medical Institute (F.U.R. and K.M.S.), University of California, San Francisco, San Francisco, California uchida@med.kobe-u.ac.jp mark.vonzastrow@ucsf.edu.
Yasunori
Y
Uchida
Department of Psychiatry (Y.U., D.J., and M.Z.), Department of Cellular and Molecular Pharmacology (F.U.R., K.M.S., and M.Z.), and Howard Hughes Medical Institute (F.U.R. and K.M.S.), University of California, San Francisco, San Francisco, California.
Florentine U
FU
Rutaganira
Department of Psychiatry (Y.U., D.J., and M.Z.), Department of Cellular and Molecular Pharmacology (F.U.R., K.M.S., and M.Z.), and Howard Hughes Medical Institute (F.U.R. and K.M.S.), University of California, San Francisco, San Francisco, California.
Damien
D
Jullié
Department of Psychiatry (Y.U., D.J., and M.Z.), Department of Cellular and Molecular Pharmacology (F.U.R., K.M.S., and M.Z.), and Howard Hughes Medical Institute (F.U.R. and K.M.S.), University of California, San Francisco, San Francisco, California.
Kevan M
KM
Shokat
Department of Psychiatry (Y.U., D.J., and M.Z.), Department of Cellular and Molecular Pharmacology (F.U.R., K.M.S., and M.Z.), and Howard Hughes Medical Institute (F.U.R. and K.M.S.), University of California, San Francisco, San Francisco, California uchida@med.kobe-u.ac.jp mark.vonzastrow@ucsf.edu.
Mark
M
von Zastrow
D058546:Class III Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism; D011992:Endosomes / Q000201:enzymology*; D057809:HEK293 Cells; D006801:Humans; D008954:Models, Biological; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism; D018343:Receptors, Adrenergic, beta-2 / Q000378:metabolism*; D015398:Signal Transduction
D018129:Phosphatidylinositol Phosphates; D018343:Receptors, Adrenergic, beta-2; C055525:phosphatidylinositol 3-phosphate; D000242:Cyclic AMP; D058546:Class III Phosphatidylinositol 3-Kinases