Activation of Heterotrimeric G Proteins

Cismowski, M. J. (2006) Non-receptor activators of heterotrimeric G-protein signaling (AGS proteins). Semin. Cell Dev. Biol. 17, 334-344. 

Activation of heterotrimeric G-proteins independent of a G-protein coupied receptor and the impiications for signai processing... 

Cismowski MJ, Ma C, Ribas C, Xie X, Spruyt M, Lizano JS, Lanier SM, Duzic E (2000) Activation of heterotrimeric G-protein signaling by a ras-related protein implications for signal integration. J Biol Chem 275 23421-23424... 

Takesono A, Cismowski Ml, Ribas C, Bernard M, Chung P, Hazard 111 S, Duzic E, Lanier SM (1999) Receptor-independent activators of heterotrimeric G-protein signaling pathways. J Biol Chem 274 33202-33205... 

Fig. 5.5. General functions of transmembrane receptors. Extracellular signals convert the transmembrane receptor from the inactive form R to the active form R. The activated receptor transmits the signal to effector proteins next in the reaction sequence. Important effector reactions are the activation of heterotrimeric G-proteins, of protein tyrosine kinases and of protein tyrosine phosphatases. The tyrosine kinases and tyrosine phosphatases may be an intrinsic part of the receptor or they may be associated with the receptor. The activated receptor may also include adaptor proteins in the signaling pathway or it may induce opening of ion channels.

Cuello, F. Schulze, R.A. Heemeyer, F. Meyer, H.E. Lutz, S. Jakobs, K.H. Niroomand, F. Wieland, T. Activation of heterotrimeric G proteins by a high energy phosphate transfer via nucleoside diphosphate kinase (NDPK) B and Gb subunits. J. Biol. Chem., 278, 7220-7226 (2003)... 

The carboxyl terminus of the Ga-subunit is the latch for triggered activation of heterotrimeric G proteins. Mol. Pharmacol. 69, 397-405. 

Nanoff, C., Koppensteiner, R., Yang, Q., Fuerst, E., Ahom, H., and Freissmuth, M. (2006). The carboxyl terminus of the G alpha-subunit is the latch for triggered activation of heterotrimeric G proteins. Mol. Pharmacol. 69, 397-405. 

Janetopoulos, C., Jin, T., and Devreotes, P. (2001). Receptor-mediated activation of heterotrimeric G-proteins in living cells. Science 291, 2408-2411. 

Plate 7 Ribbon presentation of the a,/3,yholocomplex of transducin. The GTPase activity of heterotrimeric G proteins, resides in the iarger, 42-45 kOa, a-subunits with the helical domain, (left). The Go subunit is in green. The G /3-subunit is in dark blue and the G y-subunit is in light blue. (Reproduced with permission of the authors and Nature from ref. 86 in Chapter 3.)... 

What is the basic structure of a G-protein coupled receptor How does agonist binding to the receptor lead to the activation of heterotrimeric G-proteins ... 

Ligand Binding to 7TM Receptors Leads to the Activation of Heterotrimeric G Proteins... 

SST receptors mediate their effects by coupling to and activation of heterotrimeric G proteins which, among other things, is indicated by the observations that GTP decreases their affinity to the peptide (Koch and Schonbrunn 1984). Pertussis toxin (PTX)-sensitive and -insensitive G proteins or pathways have been reported to couple SST receptors to their cellular effectors (Koch and Schonbrunn 1984 Koch et al. 1985 Barber et... 

---