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Engineering GPCR signaling pathways with RASSLs


We are creating families of designer G protein–coupled receptors (GPCRs) to allow for precise spatiotemporal control of GPCR signaling in vivo. These engineered GPCRs, called receptors activated solely by synthetic ligands (RASSLs), are unresponsive to endogenous ligands but can be activated by nanomolar concentrations of pharmacologically inert, drug-like small molecules. Currently, RASSLs exist for the three major GPCR signaling pathways (Gs, Gi and Gq). We review these advances here to facilitate the use of these powerful and diverse tools.

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Figure 1: Creating RASSLs by targeted mutagenesis.
Figure 2: Ligand-dependent and -independent phenotypes are induced by tissue-specific expression of a hRO-i, a Gi RASSL.
Figure 3: Directed molecular evolution to create new RASSLs.


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We thank our funding agencies and the members of our labs who have contributed to the RASSL projects: US National Institutes of Health (HL60664-07 to B.R.C.; DK072071 to R.A.N.; and U19MH82441 to B.L.R), a National Alliance for Research on Schizophrenia and Depression Distinguished Investigator Award (to B.L.R.), the American Heart Association pre-doctoral fellowship program (0415005Y to W.C.C.), the Veterans Affairs Merit Review and Career Scientist Program (R.A.N.) and the Gladstone–California Institute of Regenerative Medicine, fellowship program (grant T2-00003 to E.C.H.). The Gladstone Institutes received support from the US National Center for Research Resources Grant RR18928-01. We thank J. Ng, T. Nguyen, D. Srivastava, R.W. Mahley, H. Zahed, B. Phillips, M. Spindler, G. Howard and S. Ordway for providing valuable technical assistance and discussions.

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Correspondence to Bruce R Conklin or Bryan L Roth.

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Conklin, B., Hsiao, E., Claeysen, S. et al. Engineering GPCR signaling pathways with RASSLs. Nat Methods 5, 673–678 (2008).

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