caa a22 4500 397558716 CHVBK 20180308164810.0 cr unu---uuuuu 161202e199611 xx s 000 0 eng 10.1093/oxfordjournals.jbchem.a021518 doi (NATIONALLICENCE)oxford-10.1093/oxfordjournals.jbchem.a021518 Importance of N-Terminal Regions of G Protein α Subunits for the Activation of Phospholipase C in Xenopus Oocytes [Elektronische Daten] [Koji Nakamura, Toshihide Nukada, Kohbun Imai, Hiroyuki Sugiyama] The α subunits of Gq family G proteins, GL1 a and GL2 a, are bovine homologues of mouse GL4α and GL1α, respectively, and are closely related to each other. When expressed in Xenopus oocytes together with metabotropic glutamate receptors, GL2α activates endogenous phospholipase C (PLCx) in response to glutamate stimulation, whereas GL1α inhibits the activation of PLCx. By examining the properties of 10 chimeras between GL1α and GL2α and their mutants, we tried to identify the regions on the Gα proteins that are important for the activation of PLCx. The results indicated that a necessary (but not sufficient) condition for a chimeric Gα protein to be able to clearly activate PLCx was that its N-terminal quarter portion should be derived from GL2α. No correlation was found between the origin (GL1α or GL2α) of C-terminal regions of the chimeras and the ability of chimeras to activate PLCx. One of the chimeras is different from GL2α at only four amino acid residues in the N-terminal region, and yet it could not activate PLCx. When one of the four residues, Ser-59, in the chimera was mutated back to Ala as in the original GL2α, the resulting mutant became capable of activating PLCx. This residue is localized in the midst of the N-terminal linker connecting the two major domains in the Gα proteins. These results indicate that Ala-59 is critical for the activation of PLCx, and that the linker may play important roles in determining functions of Gα proteins. © 1996 BY THE JOURNAL OF BIOCHEMISTRY Regular Papers nationallicence chimera nationallicence glutamate receptor nationallicence G protein nationallicence oocyte nationallicence phospholipase C nationallicence Nakamura Koji Department of Molecular Biology, Graduate School of Medical Science, Kyushu University Fukuoka 812 aut Nukada Toshihide Department of Neurochemistry, Tokyo Institute of Psychiatry Tokyo 156 aut Imai Kohbun Department of Neurochemistry, Tokyo Institute of Psychiatry Tokyo 156 aut Sugiyama Hiroyuki Department of Molecular Biology, Graduate School of Medical Science, Kyushu University Fukuoka 812 aut The Journal of Biochemistry Oxford University Press 120/5(1996-11), 996-1001 0021-924X 120:5<996 1996 120 jbchem https://doi.org/10.1093/oxfordjournals.jbchem.a021518 text/html Onlinezugriff via DOI 1 other jats NATIONALLICENCE 856 40 https://doi.org/10.1093/oxfordjournals.jbchem.a021518 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Nakamura Koji Department of Molecular Biology, Graduate School of Medical Science, Kyushu University Fukuoka 812 aut NATIONALLICENCE 700 1- Nukada Toshihide Department of Neurochemistry, Tokyo Institute of Psychiatry Tokyo 156 aut NATIONALLICENCE 700 1- Imai Kohbun Department of Neurochemistry, Tokyo Institute of Psychiatry Tokyo 156 aut NATIONALLICENCE 700 1- Sugiyama Hiroyuki Department of Molecular Biology, Graduate School of Medical Science, Kyushu University Fukuoka 812 aut NATIONALLICENCE 773 0- The Journal of Biochemistry Oxford University Press 120/5(1996-11), 996-1001 0021-924X 120:5<996 1996 120 jbchem Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford