58 ACTIVATION OF G PROTEINS BY REGULATORS [4] treatment can produce functional changes in receptor/G protein coupling in brain without affecting receptor number, this approach is crucial in understanding effects on receptor function. Acknowledgment Our work has been supported by grants from the National Institute on Drug Abuse, including DA-00287 (L.J.S.) and DA-06634, DA06784, and DA02984 (S.R.C.). 42 j. W. Laitinen and M. Jokinen, J. Neurochem. 71, 808 (1998). 43 L. J. Sim, R. Xiao, and S. R. Childers, Brain Res. Bull. 44, 39 (1997). 44 D. S. Dupuis, M. Perez, S. Halazy, E C. Colpaert, and P. J. Pauwels, Mol. Brain Res. 67, 107 (1999). 45 L. J. Sim and S. R. Childers, J. Comp. Neurol. 386, 562 (1997). 46 M. L. Capece, H. A. Baghdoyan, and R. Lydic, J. Neurosci. 18, 3779 (1998). 47 R. J. Primus, E. Yevich, and D. W. Gallager, Mol. Brain Res. 58, 74 (1998). 48 I. Shimohira, S. Tokuyama, A. Himeno, M. Niwa, and H. Ueda, Neuroscience Letters 237, 113 (1997). 49 U. H. Winzer-Serhan and E M. Leslie, J. NeurobioL 38, 259 (1999). [4] Design and Use of C-Terminal Minigene Vectors for Studying Role of Heterotrimeric G Proteins By ANNETTE GILCHRIST, ANLI LI, and HEIDI E. HAMM Introduction Many biologically active molecules convey their signals via receptors cou- pled to heterotrimeric guanine nucleotide binding proteins (G proteins). Molec- ular cloning has resulted in the identification of 16 distinct Got subunits which are commonly divided into four families based on their sequence similarity (see review 1). The Gi family includes Gt, Ggust,Gil, Gi2, Gi3, Gol, Go2, and Gz; the Gs family members are Gs and Golf; the Gq family includes Gq, Gn, G14, and GI5/t6; and the G12/G13 family members are G12 and G13. Similarly, five G/3 and 11 Gy subunits have been identified (see review 1). On activation, G-protein-coupled receptors (GPCRs) interact with their cog- nate heterotrimeric G protein, inducing GDP release with subsequent GTP bind- ing to the a subunit (see reviews 2, 3). The exchange of GDP for GTP leads to I S. Rens-Domiano and H. E. Hamm, FASEB J. 9, 1059 (1995). Copyright © 2002by Academic Press All rights of reproduction in any formreserved. METHODS IN ENZYMOLOGY, VOL.344 0076-6879/02 $35.00