Abstract
Multiple signal transduction pathways within a single cell may share common components. In particular, seven different transmembrane helix receptors may activate identical pathways by interacting with the same G-proteins. Dictyostelium cells respond to cAMP using one such receptor, cAR1, coupled by a typical heterotrimeric G-protein to intracellular effectors. However, cells in which the gene for cAR1 has been deleted are unexpectedly still able to respond to cAMP. This implies either that certain responses are mediated by a different receptor than cAR1, or alternatively that a second, partially redundant receptor shares some of the functions of cAR1. We have examined the dose response and ligand specificity of one response, cAMP relay, and the dose response of another, cyclic GMP synthesis. In each case, the EC50 was approximately 100-fold higher and the maximal response was smaller in car1- than wild-type cells. These data indicate that cAR1 normally mediates responses to cAMP. The ligand specificity suggests that the responses seen in car1- mutants are mediated by a second receptor, cAR3. To test this hypothesis, we constructed a cell line containing deletions of both cAR1 and cAR3 genes. As predicted, these lines are totally insensitive to cAMP. We conclude that the functions of the cAR1 and cAR3 receptors are partially redundant and that both interact with the same heterotrimeric G-protein to mediate these and other responses.
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- Boy-Marcotte E., Vilaine F., Camonis J., Jacquet M. A DNA sequence from Dictyostelium discoideum complements ura3 and ura5 mutations of Saccharomyces cerevisiae. Mol Gen Genet. 1984;193(3):406–413. doi: 10.1007/BF00382076. [DOI] [PubMed] [Google Scholar]
- Darmon M., Brachet P., Da Silva L. H. Chemotactic signals induce cell differentiation in Dictyostelium discoideum. Proc Natl Acad Sci U S A. 1975 Aug;72(8):3163–3166. doi: 10.1073/pnas.72.8.3163. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Devreotes P. N., Derstine P. L., Steck T. L. Cyclic 3',5' AMP relay in Dictyostelium discoideum. I. A technique to monitor responses to controlled stimuli. J Cell Biol. 1979 Feb;80(2):291–299. doi: 10.1083/jcb.80.2.291. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Devreotes P. N., Steck T. L. Cyclic 3',5' AMP relay in Dictyostelium discoideum. II. Requirements for the initiation and termination of the response. J Cell Biol. 1979 Feb;80(2):300–309. doi: 10.1083/jcb.80.2.300. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Devreotes P. Dictyostelium discoideum: a model system for cell-cell interactions in development. Science. 1989 Sep 8;245(4922):1054–1058. doi: 10.1126/science.2672337. [DOI] [PubMed] [Google Scholar]
- Dinauer M. C., MacKay S. A., Devreotes P. N. Cyclic 3',5'-AMP relay in Dictyostelium discoideum III. The relationship of cAMP synthesis and secretion during the cAMP signaling response. J Cell Biol. 1980 Aug;86(2):537–544. doi: 10.1083/jcb.86.2.537. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Franke J., Kessin R. A defined minimal medium for axenic strains of Dictyostelium discoideum. Proc Natl Acad Sci U S A. 1977 May;74(5):2157–2161. doi: 10.1073/pnas.74.5.2157. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Johnson R. L., Van Haastert P. J., Kimmel A. R., Saxe C. L., 3rd, Jastorff B., Devreotes P. N. The cyclic nucleotide specificity of three cAMP receptors in Dictyostelium. J Biol Chem. 1992 Mar 5;267(7):4600–4607. [PubMed] [Google Scholar]
- Kimmel A. R. Different molecular mechanisms for cAMP regulation of gene expression during Dictyostelium development. Dev Biol. 1987 Jul;122(1):163–171. doi: 10.1016/0012-1606(87)90342-3. [DOI] [PubMed] [Google Scholar]
- Klein P. S., Sun T. J., Saxe C. L., 3rd, Kimmel A. R., Johnson R. L., Devreotes P. N. A chemoattractant receptor controls development in Dictyostelium discoideum. Science. 1988 Sep 16;241(4872):1467–1472. doi: 10.1126/science.3047871. [DOI] [PubMed] [Google Scholar]
- Kumagai A., Hadwiger J. A., Pupillo M., Firtel R. A. Molecular genetic analysis of two G alpha protein subunits in Dictyostelium. J Biol Chem. 1991 Jan 15;266(2):1220–1228. [PubMed] [Google Scholar]
- Lilly P. J., Devreotes P. N. Identification of CRAC, a cytosolic regulator required for guanine nucleotide stimulation of adenylyl cyclase in Dictyostelium. J Biol Chem. 1994 May 13;269(19):14123–14129. [PubMed] [Google Scholar]
- Lilly P., Wu L., Welker D. L., Devreotes P. N. A G-protein beta-subunit is essential for Dictyostelium development. Genes Dev. 1993 Jun;7(6):986–995. doi: 10.1101/gad.7.6.986. [DOI] [PubMed] [Google Scholar]
- Newell P. C., Liu G. Streamer F mutants and chemotaxis of Dictyostelium. Bioessays. 1992 Jul;14(7):473–479. doi: 10.1002/bies.950140708. [DOI] [PubMed] [Google Scholar]
- Pitt G. S., Milona N., Borleis J., Lin K. C., Reed R. R., Devreotes P. N. Structurally distinct and stage-specific adenylyl cyclase genes play different roles in Dictyostelium development. Cell. 1992 Apr 17;69(2):305–315. doi: 10.1016/0092-8674(92)90411-5. [DOI] [PubMed] [Google Scholar]
- Pupillo M., Insall R., Pitt G. S., Devreotes P. N. Multiple cyclic AMP receptors are linked to adenylyl cyclase in Dictyostelium. Mol Biol Cell. 1992 Nov;3(11):1229–1234. doi: 10.1091/mbc.3.11.1229. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Pupillo M., Kumagai A., Pitt G. S., Firtel R. A., Devreotes P. N. Multiple alpha subunits of guanine nucleotide-binding proteins in Dictyostelium. Proc Natl Acad Sci U S A. 1989 Jul;86(13):4892–4896. doi: 10.1073/pnas.86.13.4892. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Saxe C. L., 3rd, Ginsburg G. T., Louis J. M., Johnson R., Devreotes P. N., Kimmel A. R. CAR2, a prestalk cAMP receptor required for normal tip formation and late development of Dictyostelium discoideum. Genes Dev. 1993 Feb;7(2):262–272. doi: 10.1101/gad.7.2.262. [DOI] [PubMed] [Google Scholar]
- Saxe C. L., 3rd, Johnson R. L., Devreotes P. N., Kimmel A. R. Expression of a cAMP receptor gene of Dictyostelium and evidence for a multigene family. Genes Dev. 1991 Jan;5(1):1–8. doi: 10.1101/gad.5.1.1. [DOI] [PubMed] [Google Scholar]
- Saxe C. L., 3rd, Johnson R., Devreotes P. N., Kimmel A. R. Multiple genes for cell surface cAMP receptors in Dictyostelium discoideum. Dev Genet. 1991;12(1-2):6–13. doi: 10.1002/dvg.1020120104. [DOI] [PubMed] [Google Scholar]
- Schaap P., Konijn T. M., van Haastert P. J. cAMP pulses coordinate morphogenetic movement during fruiting body formation of Dictyostelium minutum. Proc Natl Acad Sci U S A. 1984 Apr;81(7):2122–2126. doi: 10.1073/pnas.81.7.2122. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schaap P., van Driel R. V. Induction of post-aggregative differentiation in Dictyostelium discoideum by cAMP. Evidence of involvement of the cell surface cAMP receptor. Exp Cell Res. 1985 Aug;159(2):388–398. doi: 10.1016/s0014-4827(85)80012-4. [DOI] [PubMed] [Google Scholar]
- Snaar-Jagalska B. E., Van Haastert P. J. Pertussis toxin inhibits cAMP-induced desensitization of adenylate cyclase in Dictyostelium discoideum. Mol Cell Biochem. 1990 Feb 9;92(2):177–189. doi: 10.1007/BF00218135. [DOI] [PubMed] [Google Scholar]
- Sun T. J., Devreotes P. N. Gene targeting of the aggregation stage cAMP receptor cAR1 in Dictyostelium. Genes Dev. 1991 Apr;5(4):572–582. doi: 10.1101/gad.5.4.572. [DOI] [PubMed] [Google Scholar]
- Sun T. J., Van Haastert P. J., Devreotes P. N. Surface cAMP receptors mediate multiple responses during development in Dictyostelium: evidenced by antisense mutagenesis. J Cell Biol. 1990 May;110(5):1549–1554. doi: 10.1083/jcb.110.5.1549. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Theibert A., Devreotes P. N. Surface receptor-mediated activation of adenylate cyclase in Dictyostelium. Regulation by guanine nucleotides in wild-type cells and aggregation deficient mutants. J Biol Chem. 1986 Nov 15;261(32):15121–15125. [PubMed] [Google Scholar]
- Theibert A., Palmisano M., Jastorff B., Devreotes P. The specificity of the cAMP receptor mediating activation of adenylate cyclase in Dictyostelium discoideum. Dev Biol. 1986 Apr;114(2):529–533. doi: 10.1016/0012-1606(86)90216-2. [DOI] [PubMed] [Google Scholar]
- Van Haastert P. J. The modulation of cell surface cAMP receptors from Dictyostelium discoideum by ammonium sulfate. Biochim Biophys Acta. 1985 May 30;845(2):254–260. doi: 10.1016/0167-4889(85)90184-3. [DOI] [PubMed] [Google Scholar]
- Watts D. J., Ashworth J. M. Growth of myxameobae of the cellular slime mould Dictyostelium discoideum in axenic culture. Biochem J. 1970 Sep;119(2):171–174. doi: 10.1042/bj1190171. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wu L., Gaskins C., Zhou K., Firtel R. A., Devreotes P. N. Cloning and targeted mutations of G alpha 7 and G alpha 8, two developmentally regulated G protein alpha-subunit genes in Dictyostelium. Mol Biol Cell. 1994 Jun;5(6):691–702. doi: 10.1091/mbc.5.6.691. [DOI] [PMC free article] [PubMed] [Google Scholar]